Interactions between prolactin and kisspeptin to control reproduction

ABSTRACT Prolactin is best known for its effects of stimulating mammary gland development and lactogenesis. However, prolactin is a pleiotropic hormone that is able to affect several physiological functions, including fertility. Prolactin receptors (PRLRs) are widely expressed in several tissues, including several brain regions and reproductive tract organs. Upon activation, PRLRs may exert prolactin’s functions through several signaling pathways, although the recruitment of the signal transducer and activator of transcription 5 causes most of the known effects of prolactin. Pathological hyperprolactinemia is mainly due to the presence of a prolactinoma or pharmacological effects induced by drugs that interact with the dopamine system. Notably, hyperprolactinemia is a frequent cause of reproductive dysfunction and may lead to infertility in males and females. Recently, several studies have indicated that prolactin may modulate the reproductive axis by acting on specific populations of hypothalamic neurons that express the Kiss1 gene. The Kiss1 gene encodes neuropeptides known as kisspeptins, which are powerful activators of gonadotropin-releasing hormone neurons. In the present review, we will summarize the current knowledge about prolactin’s actions on reproduction. Among other aspects, we will discuss whether the interaction between prolactin and the Kiss1-expressing neurons can affect reproduction and how kisspeptins may become a novel therapeutic approach to treat prolactin-induced infertility.

The effects of sIL-2R in plasma on regulatory T cells in children with acute Kawasaki disease / 中华微生物学和免疫学杂志

Objective To investigate the effects of sIL-2R in plasma on regulatory T cells (Treg) in children with Kawasaki disease ( KD ) .Methods Thirty-three children with KD and fourteen age-matched healthy children were enrolled in this study .The proportions of CD4+CD25+Foxp3+Treg cells in pe-ripheral blood and mean fluorescence intensity (MFI) of phosphorylated-STAT5 (pSTAT5) protein in CD4+CD25+T cells were analyzed by flow cytometry .The concentrations of sIL-2R, IL-2, IL-7 and IL-15 in plas-ma were measured by cytometric bead array ( CBA ) .Real-time PCR was performed to detect the gene ex-pressions of Foxp3, GITR, CTLA4, IL-2Rα, IL-2Rβand IL-2Rγat mRNA level as well as the expressions of IL-17A and ROR-γt at mRNA level in CD4+CD25-T cells.Results (1) Compared with the control group, the proportions of CD4+CD25+Foxp3+Treg cells in peripheral blood from patients with KD and the expressions of associated factors including Foxp 3, GITR and CTLA-4 at mRNA level were significantly down-regulated (P0.05).(4)The expressions of IL-2Rαand IL-2Rβat mRNA level in CD4+CD25+T cells from patients with acute KD were lower than those of the healthy subjects (P0.05).The concentrations of sIL-2R in plasma were negatively correlated with the expressions of IL-2Rβand Foxp3 at mRNA level and pSTAT5 at protein level (P<0.05).The expression of pSTAT5 protein had positive correlation with the ex-pression of Foxp3 at mRNA level (P<0.05).Conclusion Aberrant IL-2/STAT5 signaling pathway media-ted by significantly increased concentration of sIL-2R in plasma might be one of the factors leading to down-regulation of Treg cells in patients with acute KD .