Prokineticins in central and peripheral control of human reproduction
HORMONE MOLECULAR BIOLOGY AND CLINICAL INVESTIGATION
Authors: Traboulsi, Wael; Brouillet, Sophie; Sergent, Frederic; Boufettal, Houssine; Samouh, Naima; Aboussaouira, Touria; Hoffmann, Pascale; Feige, Jean Jacques; Benharouga, Mohamed; Alfaidy, Nadia
Abstract
Prokineticin 1 (PROK1) and (PROK2), are two closely related proteins that were identified as the mammalian homologs of their two amphibian homologs, mamba intestinal toxin (MIT-1) and Bv8. PROKs activate two G-protein linked receptors (prokineticin receptor 1 and 2, PROKR1 and PROKR2). Both PROK1 and PROK2 have been found to regulate a stunning array of biological functions. In particular, PROKs stimulate gastrointestinal motility, thus accounting for their family name "prokineticins". PROK1 acts as a potent angiogenic mitogen, thus earning its other name, endocrine gland-derived vascular endothelial factor. In contrast, PROK2 signaling pathway has been shown to be a critical regulator of olfactory bulb morphogenesis and sexual maturation. During the last decade, strong evidences established the key roles of prokineticins in the control of human central and peripheral reproductive processes. PROKs act as main regulators of the physiological functions of the ovary, uterus, placenta, and testis, with marked dysfunctions in various pathological conditions such as recurrent pregnancy loss, and preeclampsia. PROKs have also been associated to the tumor development of some of these organs. In the central system, prokineticins control the migration of GnRH neurons, a key process that controls reproductive functions. Importantly, mutations in PROK2 and PROKR2 are associated to the development of Kallmann syndrome, with direct consequences on the reproductive system. This review describes the finely tuned actions of prokineticins in the control of the central and peripheral reproductive processes. Also, it discusses future research directions for the use of these cytokines as diagnostic markers for several reproductive diseases.
Hirschsprung's disease and variants in genes that regulate enteric neural crest cell proliferation, migration and differentiation
JOURNAL OF HUMAN GENETICS
Authors: Carter, Tonia C.; Kay, Denise M.; Browne, Marilyn L.; Liu, Aiyi; Romitti, Paul A.; Kuehn, Devon; Conley, Mary R.; Caggana, Michele; Druschel, Charlotte M.; Brody, Lawrence C.; Mills, James L.
Abstract
Hirschsprung's disease (HSCR) results from failed colonization of the embryonic gut by enteric neural crest cells (ENCCs); colonization requires RET proto-oncogene (RET) signaling. We sequenced RET to identify coding and splice-site variants in a population-based case group and we tested for associations between HSCR and common variants in RET and candidate genes (ASCL1, homeobox B5 (HOXB5), L1 cell adhesion molecule (L1CAM), paired-like homeobox 2b (PHOX2B), PROK1 and PROKR1) chosen because they are involved in ENCC proliferation, migration and differentiation in animal models. We conducted a nested case-control study of 304 HSCR cases and 1215 controls. Among 38 (12.5%) cases with 34 RET coding and splice-site variants, 18 variants were previously unreported. We confirmed associations with common variants in HOXB5 and PHOX2B but the associations with variants in ASCL1, L1CAM and PROK1 were not significant after multiple comparisons adjustment. RET variants were strongly associated with HSCR (P-values between 10(-3) and 10(-31)) but this differed by race/ethnicity: associations were absent in African-Americans. Our population-based study not only identified novel RET variants in HSCR cases, it showed that common RET variants may not contribute to HSCR in all race/ethnic groups. The findings for HOXB5 and PHOX2B provide supportive evidence that genes regulating ENCC proliferation, migration and differentiation could be risk factors for HSCR. Journal of Human Genetics (2012) 57, 485-493; doi: 10.1038/jhg.2012.54; published online 31 May 2012