TY - JOUR
T1 - Sushi repeat-containing protein X-linked 2: A novel phylogenetically conserved hypothalamo-pituitary protein
AU - Anwer, Mehwish
AU - Bolkvadze, Tamuna
AU - Ndode-Ekane, Xavier Ekolle
AU - Puhakka, Noora
AU - Rauramaa, Tuomas
AU - Leinonen, Ville
AU - van Vliet, Erwin A.
AU - Swaab, Dick F.
AU - Haapasalo, Annakaisa
AU - Leskelä, Stina
AU - Bister, Nea
AU - Malm, Tarja
AU - Carlson, Synnöve
AU - Aronica, Eleonora
AU - Pitkänen, Asla
PY - 2018
Y1 - 2018
N2 - Sushi repeat-containing protein X-linked 2 (SRPX2) is a novel protein associated with language development, synaptic plasticity, tissue remodeling, and angiogenesis. We investigated the expression and spatial localization of SRPX2 in normal mouse, rat, monkey, and human brain using in situ hybridization and immunohistochemistry. Antibody specificity was determined using in vitro siRNA based silencing of SRPX2. Cell type-specific expression was verified by double-labeling with oxytocin or vasopressin. Western blot was used to detect SRPX2 protein in rat and human plasma and cerebrospinal fluid. Unexpectedly, SRPX2 mRNA expression levels were strikingly higher in the hypothalamus as compared to the cortex. All SRPX2 immunoreactive (ir) neurons were localized in the hypothalamic paraventricular, periventricular, and supraoptic nuclei in mouse, rat, monkey, and human brain. SRPX2 colocalized with vasopressin or oxytocin in paraventricular and supraoptic neurons. Hypothalamic SRPX2-ir positive neurons gave origin to dense projections traveling ventrally and caudally toward the hypophysis. Intense axonal varicosities and terminal arborizations were identified in the rat and human neurohypophysis. SRPX2-ir cells were also found in the adenohypophysis. Light SRPX2-ir projections were observed in the dorsal and ventral raphe, locus coeruleus, and the nucleus of the solitary tract in mouse, rat and monkey. SRPX2 protein was also detected in plasma and CSF. Our data revealed intense phylogenetically conserved expression of SRPX2 protein in distinct hypothalamic nuclei and the hypophysis, suggesting its active role in the hypothalamo-pituitary axis. The presence of SRPX2 protein in the plasma and CSF suggests that some of its functions depend on secretion into body fluids.
AB - Sushi repeat-containing protein X-linked 2 (SRPX2) is a novel protein associated with language development, synaptic plasticity, tissue remodeling, and angiogenesis. We investigated the expression and spatial localization of SRPX2 in normal mouse, rat, monkey, and human brain using in situ hybridization and immunohistochemistry. Antibody specificity was determined using in vitro siRNA based silencing of SRPX2. Cell type-specific expression was verified by double-labeling with oxytocin or vasopressin. Western blot was used to detect SRPX2 protein in rat and human plasma and cerebrospinal fluid. Unexpectedly, SRPX2 mRNA expression levels were strikingly higher in the hypothalamus as compared to the cortex. All SRPX2 immunoreactive (ir) neurons were localized in the hypothalamic paraventricular, periventricular, and supraoptic nuclei in mouse, rat, monkey, and human brain. SRPX2 colocalized with vasopressin or oxytocin in paraventricular and supraoptic neurons. Hypothalamic SRPX2-ir positive neurons gave origin to dense projections traveling ventrally and caudally toward the hypophysis. Intense axonal varicosities and terminal arborizations were identified in the rat and human neurohypophysis. SRPX2-ir cells were also found in the adenohypophysis. Light SRPX2-ir projections were observed in the dorsal and ventral raphe, locus coeruleus, and the nucleus of the solitary tract in mouse, rat and monkey. SRPX2 protein was also detected in plasma and CSF. Our data revealed intense phylogenetically conserved expression of SRPX2 protein in distinct hypothalamic nuclei and the hypophysis, suggesting its active role in the hypothalamo-pituitary axis. The presence of SRPX2 protein in the plasma and CSF suggests that some of its functions depend on secretion into body fluids.
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85046120108&origin=inward
UR - https://www.ncbi.nlm.nih.gov/pubmed/29663392
U2 - https://doi.org/10.1002/cne.24449
DO - https://doi.org/10.1002/cne.24449
M3 - Article
C2 - 29663392
SN - 0021-9967
VL - 526
SP - 1806
EP - 1819
JO - Journal of comparative neurology
JF - Journal of comparative neurology
IS - 11
ER -