title: Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury.
abstract: Neuronal calcium (Ca(2+))-binding proteins 1 and 2 (NECAB1/2) are members of the phylogenetically conserved EF-hand Ca(2+)-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 Ca(2+)-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 Ca(2+)-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.
authors.affiliation: Department of Neuroscience, Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, and Science for Life Laboratory, Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden.
authors.forename: Ming-Dong
authors.initials: MD
authors.lastname: Zhang
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Tortoriello
authors.forename: Brian
authors.initials: B
authors.lastname: Hsueh
authors.forename: Raju
authors.initials: R
authors.lastname: Tomer
authors.forename: Li
authors.initials: L
authors.lastname: Ye
authors.forename: Nicholas
authors.initials: N
authors.lastname: Mitsios
authors.forename: Lotta
authors.initials: L
authors.lastname: Borgius
authors.forename: Gunnar
authors.initials: G
authors.lastname: Grant
authors.forename: Ole
authors.initials: O
authors.lastname: Kiehn
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
authors.forename: Mathias
authors.initials: M
authors.lastname: Uhlén
authors.forename: Jan
authors.initials: J
authors.lastname: Mulder
authors.forename: Karl
authors.initials: K
authors.lastname: Deisseroth
authors.forename: Tibor
authors.initials: T
authors.lastname: Harkany
authors.forename: Tomas G M
authors.initials: TG
authors.lastname: Hökfelt
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009474:Neurons / Q000378:metabolism*; D010146:Pain / Q000378:metabolism; D059348:Peripheral Nerve Injuries / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D013116:Spinal Cord / Q000166:cytology* / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins
keywords: GAD67; VGLUT2; commissural interneurons; neuropathic pain