Anti-MAPK3 monoclonal antibody, clone Z83 Knockout Validated

A growing number of studies have been showing that dietary probiotics can exert beneficial health effects in both humans and animals. We previously demonstrated that dietary supplementation with Lactobacillus rhamnosus - a component of the human gut microflora - enhances reproduction, larval development, and the biomineralization process in Danio rerio (zebrafish). The aim of this study was to identify the pathways affected by L. rhamnosus during zebrafish larval development. Our morphological and histochemical findings show that L. rhamnosus accelerates bone deposition through stimulation of the expression of key genes involved in ossification, e.g. runt-related transcription factor 2 (runx2), Sp7 transcription factor (sp7), matrix Gla protein (mgp), and bone gamma-carboxyglutamate (gla) protein (bglap) as well as through inhibition of sclerostin (sost), a bone formation inhibitor. Western blot analysis of mitogen-activated protein kinase 1 and 3-(Mapk1 and Mapk3), which are involved in osteoblast and osteocyte differentiation, documented an increase in Mapk1 16 days post fertilization (dpf) and of Mapk3 23 dpf in individuals receiving L. rhamnosus supplementation. Interestingly, a reduction of sost detected in the same individuals suggests that the probiotic may help treat bone disorders.

The process of embryo implantation and trophoblast invasion is considered the most limiting factor in the establishment of pregnancy. Leptin was originally described as an adipocyte-derived signaling molecule for the central control of metabolism. However, it has been suggested that leptin is involved in other functions during pregnancy, particularly in the placenta, where it was found to be expressed. In the present work, we have found a stimulatory effect of 17beta-estradiol (E-2) on endogenous leptin expression, as analyzed by Western blot, in both the BeWo choriocarcinoma cell line and normal placental explants. This effect was time and dose dependent. Maximal effect was achieved at 10 nM in BeWo cells and 1 nM in placental explants. The E-2 effects involved the estrogen receptor, as the antagonist ICI 182780 inhibited E-2-induced leptin expression. Moreover, E-2 treatment enhanced leptin promoter activity up to 4-fold, as evaluated by transient transfection with a plasmid construction containing the leptin promoter region and the reporter gene luciferase. This effect was dose dependent. Deletion analysis demonstrated that a minimal promoter region between -1951 and -1847 bp is both necessary and sufficient to achieve E-2 effects. Estradiol action involved estrogen receptor 1, previously known as estrogen receptor alpha, as cotransfection with a vector encoding estrogen receptor 1 potentiated the effects of E-2 on leptin expression. Moreover, E-2 action probably involves membrane receptors too, as treatment with an estradiol-bovine serum albumin complex partially enhanced leptin expression. The effects of E-2 could be blocked by pharmacologic inhibition of MAPK and the phosphoinositide-3-kinase (PI3K) pathways with 50 mu M PD98059 and 0.1 mu M Wortmannin, respectively. Moreover, cotransfection of dominant negative mutants of MAP2K or MAPK blocked E-2 induction of leptin promoter. On the other hand, E-2 treatment promoted MAPK1/MAPK3 and AKT phosphorylation in placental cells. In conclusion, we provide evidence suggesting that E-2 induces leptin expression in trophoblastic cells, probably through genomic and nongenomic actions via crosstalk between estrogen receptor 1 and MAPK and PI3K signal transduction pathways.