Current Pharmaceutical Biotechnology - Volume 10, Issue 3, 2009

Being one of the most abundant cations in nature, calcium plays crucial roles both outside and inside the cells as a signaling ion. Changes in the extracellular free calcium concentration [Ca2+ o] activate the plasmalemmal calcium-sensing receptor (CaSR or CaR), a sevenfold transmembrane spanning protein encoded by genes mapped in human chromosome 3 (and also 19). The CaSR is activated by various ligands, such as di Read More

The extracellular calcium-sensing receptor (CaR) is a class III G-protein coupled receptor that coordinates cellular responses to changes in extracellular free Ca2+ or amino acid concentrations as well as ionic strength and pH. It regulates signalling cascades via recruiting and controlling the activities of various heterotrimeric G-proteins, including Gq/11, Gi/0, and G12/13, even Gs in some “unusual” circumstances, thereby Read More

The calcium-sensing receptor (CaSR), which is involved in systemic calcium homeostasis, has also been found to be functionally expressed on cells of the vascular wall. Its activation on perivascular nerves and endothelial cells has been shown to regulate arterial tone, peripheral vascular resistance and possibly local tissue perfusion. The expression of the CaSR on immune cells involved in vascular inflammation, such as m Read More

Bone cells, particularly osteoblasts and osteoclasts, exhibit functional responses to calcium (Ca2+). The identification of the calcium-sensing receptor (CaR) in parathyroid glands as the master regulator of parathyroid hormone (PTH) secretion proved that cells could specifically respond to changes in divalent cation concentration. Yet, after many years of study, it remains unclear whether this receptor, which has also been i Read More

Calcium-sensing receptor (CaSR), a member of family C of the G protein-coupled receptors, is expressed most abundantly in the parathyroid glands and kidney. It plays key role in these two organs because it senses changes in extracellular calcium and regulates PTH secretion and calcium reabsorption to suit the extracellular calcium concentration. In kidney, CaSR is expressed in all nephron segments. It has an inhibitory ef Read More

Dietary Ca2+ reduces colon cell proliferation and carcinogenesis, but it becomes ineffective or even tumorpromoting during carcinogenesis. It appears that Ca2+ and the colon cell CaSR together brake the massive cell production in normal colon crypts. The rapid proliferation of the transit-amplifying (TA) progeny of the colon stem cells at the bases of the crypts is driven by the “Wnt” signaling mechanism that stimulates pr Read More

Although the calcium-sensing receptor (CaSR) is expressed by all types of nerve cells in widespread areas of the human central nervous system (CNS), so far its roles in brain pathophysiology remain largely unknown. Here, we review the available evidence concerning the stages of development of sporadic late-onset Alzheimer's disease (LOAD) and the roles therein played by CaSR signaling. As the brain ages, its abil Read More

In recent years, human umbilical cord blood (HUCB) has emerged as an attractive tool for cell-based therapy. Although at present the clinical application of human umbilical cord blood is limited to the fields of hematology and oncology, a rising number of studies show potential for further application in the treatment of non-hematopoietic diseases. Stem cells (SC) from umbilical cord blood (UCB) are now a new reliable alter Read More

“Niche” is defined as a specialized regulatory microenvironment, consisting of components which control the fate specification of stem and progenitor cells, as well as maintaining their development by supplying the requisite factors. Bone marrow (BM) niche has a well-organized architecture and is composed of osteoblasts, osteoclasts, bone marrow endothelial cells, stromal cells, adipocytes and extracellular mat Read More