Nutritional control of thyroid morphogenesis through gastrointestinal hormones

New directions in epithelial mechanoadaptation

Cells are active mechanical objects: they are subject to forces, exert force, and interpret changes in force as biological information. We now understand much about how this occurs at the molecular and single-cell level. We also appreciate that mechanobiology gains even greater complexity when it operates at the multicellular level of tissues and organisms. Here, cells exert forces on other cells within tissues to support morphogenesis and homeostasis; but these forces must also be accommodated to ensure that tissue integrity is preserved. Cell-cell adhesion junctions play important roles in transmitting, resisting, as well as detecting mechanical forces in coherent tissues. In this brief article we consider how epithelia adapt to mechanical stresses, focusing on recent developments in understanding the sources of force and new mechanisms for adherens junctions and desmosomes in mechanotransduction.

Integrative approaches in Xenopus-based research: A report from the 1st Asian Xenopus Conference

The first Asian community conference on "Scientific research using Xenopus as an animal model system" was held in Osaka, Japan, from November 24 to 26, 2024. This event was organized by the Korean Society for Xenopus Development of KSMCB (Korean Society for the Molecular and Cellular Biology), Xenopus Community in Japan (XCIJ), KNU G-LAMP Project, National BioResource Project-Clawed frogs/Newts (NBRP), and Osaka University. The conference covered various research topics in biological sciences using Xenopus. The ultimate goal of this conference was to promote collaboration and encourage a new and sustainable relationship among researchers in the Asian region who utilize Xenopus in their studies by sharing scientific findings. The conference not only shared research findings from various biological fields in the Asian region but also provided opportunities to invite global experts in the Xenopus research for "Keynote Lectures" and rising researchers who use other animal models for the "Friends of Xenopus" session to foster interdisciplinary exchange. In addition, organizers planned a luncheon seminar to help trainee students learn how to write a scientific paper and how not to.

Microarray evidence that 8-cell human embryos express some hormone family members including oxytocin

OBJECTIVE

This study is to discover hormone pathways active in early cleaving human embryos.

METHODS

A list of 152 hormones and receptors were compiled to query the microarray database of mRNAs in 8-cell human embryos, two lines of human embryonic stem cells plus human fibroblasts before and after induced pluripotency.

RESULTS

Over half of the 152 hormones and receptors were silent on the arrays of all cell types, and more were detected at high or moderate levels on the 8-cell arrays than on the pluripotent cell or fibroblast arrays. Eight hormone family genes were uniquely detected at least 22-fold higher on the 8-cell arrays than the stem cell arrays: AVPI1, CCK, CORT, FSTL4, GIP, GPHA2, OXT, and PPY suggesting novel roles for these proteins in early development. Oxytocin was detected by pilot immunoassay in culture media collected from Day 3 embryos. Robust detection of CRHR1 and EPOR suggests the 8-cell embryo may be responsive to maternal CRH and EPO. The over-expression of POMC and GHITM suggests POMP peptide products may have undiscovered roles in early development and GHITM may contribute to mitochondrial remodeling. Under-detected on the 8-cell arrays at least tenfold were two key enzymes in steroid biosynthesis, DHCR24 and FDPS.

CONCLUSIONS

The 8-cell human embryo may be secreting oxytocin, which could stimulate its own progress down the fallopian tube as well as play a role in early neural precursor development. The 8-cell embryo does not synthesize reproductive steroid hormones. As previously reported for growth factor families, the early embryo over-expresses more hormones than hormone receptors.

Saponins from Camellia sinensis Seeds Stimulate GIP Secretion in Mice and STC-1 Cells via SGLT1 and TGR5

Glucose-dependent insulinotropic polypeptide (GIP) is one of the important incretins and possesses lots of physiological activities such as stimulating insulin secretion and maintaining glucose homeostasis. The pentacyclic triterpenoid saponins are the major active ingredients in tea (Camellia sinensis) seeds. This study aimed to investigate the effect of tea seed saponins on the GIP secretion and related mechanisms. Our data showed that the total tea seed saponins (TSS, 65 mg/kg BW) and theasaponin E₁ (TSE1, 2–4 µM) could increase the GIP mRNA and protein levels in mice and STC-1 cells. Phlorizin, the inhibitor of Sodium/glucose cotransporter 1 (SGLT1), reversed the TSE1-induced increase in Ca²⁺ and GIP mRNA level. In addition, TSE1 upregulated the protein expression of Takeda G protein-coupled receptor 5 (TGR5), and TGR5 siRNA significantly decreased GIP expression in TSE1-treated STC-1 cells. Network pharmacology analysis revealed that six proteins and five signaling pathways were associated with SGLT1, TGR5 and GIP regulated by TSE1. Taken together, tea seed saponins could stimulate GIP expression via SGLT1 and TGR5, and were promising natural active ingredients for improving metabolism and related diseases.