An osteoblast (from the Greek words for "bone" and "germ" or embryonic) is a mononucleate cell that is responsible for bone formation. Osteoblasts produce osteoid, which is composed mainly of Type I collagen. Osteoblasts are also responsible for mineralization of the osteoid matrix. Bone is a dynamic tissue that is constantly being reshaped by osteoblasts, which build bone, and osteoclasts, which resorb bone.
The cytoplasm of osteoblasts appears to be basophilic via normal H&E stain due to presence of large amount of rough endoplasmic reticulum. A large Golgi apparatus is also present in the centre. The nucleus is spherical and large. Osteoblasts can be stained for type 1 collagen or for the production of alkaline phosphatase.
Alkaline Phosphatase (ALP)
- a osteoblast gene marker. PMID: 16206768, PMID: 8243271, PMID: 15476586
- commonly used as "osteoblast marker" for in vitro or in vivo studies. PMID: 12110436
- AP activity (osteoblast marker) was found to be co-expressed with cytoplasmic tartrate resistant acid phosphatase (TRAP) as a marker of osteoclasts. PMID: 10879691
- bone-specific alkaline phosphatase (BAP) as a marker of osteoblasts was detected by FACS analysis in the ex vivo granuloma cells. PMID: 10879691
alpha 1(I) procollagen
- a osteoblast gene marker. PMID: 7817834, PMID: 7817834
Bone Gla Protein (BGP)
- a osteoblast gene marker. PMID: 7817834
Bone Sialoprotein (BSP)
- a bone cell differentiation marker gene. PMID: 9069167, PMID: 15476586
Cbfa1/Osf2
- known to be regulated during osteoblastic differentiation and is commonly used as "osteoblast marker" for in vitro or in vivo studies. PMID: 12110436
Collagen Type I
- a osteoblast gene marker. PMID: 16206768, PMID: 8243271
- useful to mark cells at different stages of osteoblastic differentiation. PMID: 11450698
- Serum carboxyterminal telopeptide of type 1 collagen (1CTP), a marker of osteoclastic bone resorption, was significantly raised in the dorsal venous arch of the acute Charcot foot. PMID: 9223389
E11
- a novel osteoblastic product which is expressed by mature osteoblasts and newly formed osteocytes. E11 strongly reacts with osteoblasts, preosteocytes, and osteocytes, and it recognizes an antigen localized at the cell surface. PMID: 8833206
Osteocalcin
- a osteoblast gene marker. PMID: 16206768, PMID: 8243271, PMID: 15476586
- commonly used as "osteoblast marker" for in vitro or in vivo studies. PMID: 12110436
- By RT-PCR the mRNA for osteocalcin, which is a highly specific marker for osteoblasts, was detected. PMID: 10879691
Osteopontin
- a osteoblast gene marker. PMID: 16206768, PMID: 7817834, PMID: 8243271
Phex
- a marker of the fully differentiated mature osteoblast. PMID: 10067843
RP59
- a marker for osteoblast recruitment - as a marker for cells with the capacity to differentiate into osteoblasts. PMID: 11891990
Other Osteoblast Markers
- Nuclear size as a cell-kinetic marker for osteoblast differentiation. PMID: 7158610
- This resulted in the identification of nine novel genes and ESTs that were induced specifically in osteoblasts, in addition to the well-known markers ALP and osteocalcin. PMID: 12469905
- irOCbound may be a marker for bone formation, that serum irOCfree may be a marker for bone resorption, and that the serum irOCfree/irOCbound ratio may become a marker for skeletal remodeling. PMID: 8402326