Related Experiment Video

Updated: Aug 23, 2026

Isolation of Mesenchymal Stem Cells from Human Alveolar Periosteum and Effects of Vitamin D on Osteogenic Activity of Periosteum-derived Cells
06:47

Isolation of Mesenchymal Stem Cells from Human Alveolar Periosteum and Effects of Vitamin D on Osteogenic Activity of Periosteum-derived Cells

Published on: May 4, 2018

Evidence of downregulation of matrix extracellular phosphoglycoprotein during terminal differentiation in human

H Siggelkow1, E Schmidt, B Hennies

  • 1Department of Gastroenterology and Endocrinology, Georg-August-University, Göttingen, Germany. hsiggel@med.uni-goettingen.de

Bone
|July 23, 2004
PubMed

Insights

Matrix extracellular phosphoglycoprotein (MEPE) expression differs between mice and humans. In humans, MEPE is active during early osteoblast development and suppressed during mineralization, unlike in mice.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Matrix extracellular phosphoglycoprotein (MEPE) is an extracellular matrix protein initially identified in tumor-induced osteomalacia (TIO).
  • MEPE expression in mice is maturation-dependent, peaking during bone and tooth mineralization, and it may act as a mineralization inhibitor, though its mechanism remains unclear.
  • Limited knowledge exists regarding MEPE regulation in humans.

Purpose of the Study:

  • To investigate the time- and maturation-dependent expression of MEPE in human osteoblast culture systems.
  • To examine the influence of specific factors (beta-glycerophosphate, ascorbate, TGF-beta, BMP-2, dexamethasone) on MEPE expression in human osteoblasts.

Main Methods:

  • Cultured human osteosarcoma (HOS 58) cells and primary human trabecular osteoblasts for up to 29 days.
  • Assessed MEPE gene expression under varying conditions, including the presence of beta-glycerophosphate (bGP), ascorbate, dexamethasone, TGF-beta, and BMP-2.
  • Monitored osteocalcin (OC) expression as an indicator of osteoblast differentiation and mineralization.

Main Results:

  • HOS 58 cells showed MEPE gene expression inhibition only at high concentrations (10-20 mM) of bGP, coinciding with maximal osteocalcin expression.
  • Primary human osteoblasts did not show significant MEPE gene expression changes with bGP alone.
  • Under specific differentiation-inducing conditions (5 mM bGP, ascorbate, dexamethasone for 29 days), MEPE gene expression progressively decreased to 20% of maximum, correlating with increased osteocalcin expression, indicating suppressed MEPE during mineralization.

Conclusions:

  • Contrary to mouse models, MEPE in human osteoblasts appears most active during proliferation and early matrix maturation phases.
  • MEPE expression is significantly suppressed during the mineralization phase in human osteoblasts.
  • These findings highlight species-specific differences in MEPE regulation and its role in bone mineralization.

More Related Videos

Differentiation and Characterization of Osteoclasts from Human Induced Pluripotent Stem Cells10:52

Differentiation and Characterization of Osteoclasts from Human Induced Pluripotent Stem Cells

Published on: March 22, 2024

IDG-SW3 Cell Culture in a Three-Dimensional Extracellular Matrix10:48

IDG-SW3 Cell Culture in a Three-Dimensional Extracellular Matrix

Published on: November 13, 2023

Related Concept Videos

Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...
Role of Matrix Metalloproteases in Degradation of ECM01:23

Role of Matrix Metalloproteases in Degradation of ECM

Matrix metalloproteases (MMPs) are enzymes involved in the hydrolysis of proteins and glycoproteins of the extracellular matrix. MMPs are essential for the migration and proliferation of cells through the dense matrix network, throughout embryonic development, and throughout morphogenesis. The first MMP activity discovered was a collagenase in a tadpole's tail undergoing metamorphosis. The active collagen deposition and modifications lead to the morphogenesis of tadpoles into the adult body.
A...
The Extracellular Matrix01:29

The Extracellular Matrix

Overview
In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, the molecules in the ECM maintain the structural integrity of tissue as well as the remarkable specific properties of certain tissues.
Composition of the Extracellular Matrix
The extracellular matrix (ECM) is commonly composed of ground substance, a gel-like fluid, fibrous components, and many structurally and functionally diverse...
Osteoclasts in Bone Remodeling01:31

Osteoclasts in Bone Remodeling

Osteoclasts are cells responsible for bone resorption and remodeling. They originate from hematopoietic progenitor cells present in the bone marrow. Numerous progenitor cells fuse to form multinucleated cells, each with 10-20 nuclei. A single osteoclast has a diameter of 150 to 200 µM. These cells have ruffled borders that break down the underlying bone tissue and release minerals such as calcium into the blood in bone resorption. Osteoclasts cling to bones with their ruffled edges during bone...