Related Experiment Video

Updated: Jul 17, 2026

Trabecular Bone Microarchitecture Evaluation in an Osteoporosis Mouse Model
06:59

Trabecular Bone Microarchitecture Evaluation in an Osteoporosis Mouse Model

Published on: September 8, 2023

Lifelong accumulation of bone in mice lacking Pten in osteoblasts

Ximeng Liu1, Katia J Bruxvoort, Cassandra R Zylstra

  • 1Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.

Proceedings of the National Academy of Sciences of the United States of America
|February 9, 2007
PubMed

Insights

Disrupting the Pten gene in osteoblasts boosts Akt activation, leading to enhanced bone mineral density and reduced osteoblast apoptosis. This highlights Pten

Area of Science:

  • Cell Biology
  • Bone Biology
  • Molecular Biology

Background:

  • Osteoblasts are key cells for bone formation, with their lifespan and activity regulated by growth factor signaling.
  • Phosphatidylinositol 3-kinase (PI3K)/Akt signaling promotes osteoblast survival and inhibits apoptosis.
  • Pten phosphatase negatively regulates PI3K activity, thus controlling this survival pathway.

Purpose of the Study:

  • To investigate the in vivo effects of Akt activation in bone by conditionally disrupting the Pten gene in osteoblasts.
  • To elucidate the role of Pten in regulating osteoblast lifespan and bone formation.

Main Methods:

  • Conditional disruption of the Pten gene in osteoblasts using Cre-mediated recombination in mice.
  • Analysis of bone mineral density, osteoblast differentiation, and apoptosis in Pten-deficient mice.
  • Assessment of Akt phosphorylation and downstream signaling pathways in vitro.

Main Results:

  • Mice with Pten deficiency in osteoblasts showed dramatically increased bone mineral density throughout life.
  • Osteoblasts lacking Pten exhibited accelerated differentiation and significantly reduced apoptosis.
  • Markedly increased levels of phosphorylated Akt and activation of downstream signaling were observed in Pten-deficient osteoblasts.

Conclusions:

  • Pten plays a critical role in regulating osteoblast lifespan and bone formation.
  • The tumor-suppressor gene Pten is a key regulator of the PI3K/Akt pathway in bone.
  • Dysregulation of Pten may contribute to skeletal abnormalities observed in PTEN mutation carriers.

More Related Videos

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model08:42

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

Published on: July 3, 2020

Using Inducible Osteoblastic Lineage-Specific Stat3 Knockout Mice to Study Alveolar Bone Remodeling During Orthodontic Tooth Movement05:25

Using Inducible Osteoblastic Lineage-Specific Stat3 Knockout Mice to Study Alveolar Bone Remodeling During Orthodontic Tooth Movement

Published on: July 21, 2023

Related Concept Videos

Bone Disorders01:29

Bone Disorders

Aging and its effect on bone remodeling is the most common cause of bone disorders. In young and healthy people, bone deposition and resorption happen at an equal rate to maintain optimal bone health.
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Bone Remodeling01:40

Bone Remodeling

Bone remodeling is a continuous and balanced process of bone resorption by osteoclasts and bone formation by osteoblasts. In adults, it helps maintain bone mass and calcium homeostasis. While mechanical stress can stimulate turnover as part of the normal maintenance and reparative process, several hormones also regulate bone remodeling.
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...
Bone Formation by Endochondral Ossification01:24

Bone Formation by Endochondral Ossification

Bone formation, or ossification, begins around the sixth to seventh week of embryonic development. Most bones develop from a cartilaginous template through the process of endochondral ossification. Cartilage formation begins when clusters of mesenchymal cells differentiate into chondrocytes. These chondrocytes proliferate rapidly and secrete an extracellular matrix that becomes encased in a membrane called the perichondrium. The resulting cartilage model provides a template that resembles the...
Hormones and Bone Tissue01:17

Hormones and Bone Tissue

The endocrine system produces and secretes hormones, which interact with the skeletal system. These hormones control bone growth, maintain bone once it is formed, and remodel it.
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...