Osteoporosis or porous bone is the common metabolic bone
Osteoporosis or porous bone is the common metabolic bone disorder. It has characterized by a systemic reduction of bone mineral, bone volume, and strength . Osteoporosis is a bone disease in which bones become fragile by a systemic reduction of bone mass and strength and also is controlled by an imbalance between resorption and formation of the bone [, , ]. Bone remodeling is controlled by a balance between bone resorption and formation. This balance depends on the interaction between osteoblasts, which induce new bone formation, and osteoclasts that induce bone resorption . During osteoblast differentiation, transcription factors such as osterix and Runx2 stimulate the activation of alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OSC), which lead to bone formation . The bone morphogenetic protein (BMP) was known as the growth factor superfamily, which can stimulate osteoblast differentiation in MC3T3-E1 cells. Among these BMPs, bone morphogenetic protein 2 (BMP 2) is an important in the stimulation bone formation in vitro and in vivo [9,14,15]. BMP2 also has the ability to stimulate cyclooxygenase-2 (COX-2) expression, which regulates osteoblastic differentiation in vitro . In osteoblast precursor cells, BMP 2 stimulates osteogenic action by activating Smad1/5/8, which controls the Tianeptine sodium synthesis of differentiation markers such as bone sialoprotein, ALP, OPN, and OSC . Osteogenesis is a complex process that involves both Smad1/5/8 pathway and mitogen-activated protein kinase (MAPK). The p38 and extracellular signal-regulated kinases (ERK) are important mediators in the MAPK pathway and contribute to the induction of cell differentiation [, , ]. For this study, we chose the pre-osteoblasts cells (MC3T3-El), which is commonly used as a model system to study bone formation. These cells display an orderly development in a culture characterized by the proliferation and differentiation of MC3T3-El cells, followed by proliferation, matrix maturation, and matrix mineralization phases, and display characteristics such as increased ALP activity, matrix accumulation, OSC and OPN expression, as well as eventual mineralization. Peptide-derived has potential activity as antioxidants, antihypertensives, and anticancer drugs and is widely used for bone regeneration. One of them is calcitonin, gene structures of the second calcitonin gene-related peptide from human, salmon, and C. intestinalis was identified the structure [, , ]. However, only calcitonin from human and salmon has been resulted to inhibit the bone resorption, and increase the growth of bone and cartilage [19,21]. Sekiguchi et al.  demonstrated that calcitonin from C. intestinalis is expressed more than calcitonin-vertebrate in organs. In addition, the calcitonin gene from C. intestinalis is composed of four exons and three introns, which was found to specifically inhibit osteoclasts by suppressing tartrate-resistant acid phosphatase activity . However, little is known about the influence and mechanism of sea squirt C. intestinalis calcitonin-like peptide (CCLP) on pre-osteoblast MC3T3-E1 cells. The goal of this study shows the effects of CCLP inducing osteoblast proliferation and differentiation in MC3T3-E1 cells.