Tendon stem progenitor cells: Understanding the biology to inform therapeutic strategies for tendon repair.

Tendon and ligament injuries are a leading cause of healthcare visits with significant impact in terms of economic cost and reduced quality of life. To date, reparative strategies remain largely restricted to conservative treatment or surgical repair. However, these therapies fail to restore native tendon structure and function; thus, the tissue may re-rupture or degenerate with time.

A novel role for cathepsin K in periosteal osteoclast precursors during fracture repair.

Osteoporosis management is currently centered around bisphosphonates, which inhibit osteoclast (OC) bone resorption but do not affect bone formation. This reduces fracture risk, but fails to restore healthy bone remodeling. Studies in animal models showed that cathepsin K (CatK) inhibition by genetic deletion or chemical inhibitors maintained bone formation while abrogating resorption during bone remodeling and stimulated periosteal bone modeling.

The Hajdu Cheney Mutation Is a Determinant of B-Cell Allocation of the Splenic Marginal Zone.

The neurogenic locus notch homolog protein (Notch)-2 receptor is a determinant of B-cell allocation, and gain-of-NOTCH2-function mutations are associated with Hajdu-Cheney syndrome (HCS), a disease presenting with osteoporosis and acro-osteolysis. We generated a mouse model reproducing the HCS mutation (Notch2HCS), and heterozygous global mutant mice displayed gain-of-Notch2 function. In the mutant spleen, the characteristic perifollicular rim marking the marginal zone (MZ), which is the interface between the nonlymphoid red pulp and the lymphoid white pulp, merged with components of the white pulp.

Loss of Cbl-PI3K interaction modulates the periosteal response to fracture by enhancing osteogenic commitment and differentiation.

The periosteum contains multipotent skeletal progenitors that contribute to bone repair. The signaling pathways regulating the response of periosteal cells to fracture are largely unknown. Phosphatidylinositol-3 Kinase (PI3K), a prominent lipid kinase, is a major signaling protein downstream of several factors that regulate osteoblast differentiation.

Induced pluripotent stem cells: fundamentals and applications of the reprogramming process and its ramifications on regenerative medicine.

Objective: To provide a comprehensive source of information about the reprogramming process and induced pluripotency.

Background: The ability of stem cells to renew their own population and to differentiate into specialized cell types has always attracted researchers looking to exploit this potential for cellular replacement therapies, pharmaceutical testing and studying developmental pathways. While adult stem cell therapy has already been brought to the clinic, embryonic stem cell research has been beset with legal and ethical impediments.