Our objective was to determine the content of the bioactive protein osteopontin (OPN) in bovine milk and identify factors influencing its concentration. OPN is expressed in many tissues and body fluids, with by far the highest concentrations in milk. OPN plays a role in immunological and developmental processes and it has been associated with several milk production traits and lactation persistency in cows. In the present study, we report the development of an enzyme linked immunosorbent assay (ELISA) for measurement of OPN in bovine milk. The method was used to determine the concentration of OPN in milk from 661 individual Danish Holstein cows. The median OPN level was determined to 21.9 mg/l with a pronounced level of individual variation ranging from 0.4 mg/l to 67.8 mg/l. Breeding for increased OPN in cow's milk is of significant interest, however, the heritability of OPN in milk was found to be relatively low, with an estimated value of 0.19 in the current dataset. The variation explained by the herd was also found to be low suggesting that OPN levels are not affected by farm management or feeding. Interestingly, the concentration of OPN was found to increase with days in milk and to decrease with parity.

The present study explored the mechanism of Zn-methionine (Zn-Met) influencing eggshell quality of laying hens and investigated whether the mechanism was related to Ca deposition. Hyline grey layers (n 384, 38 weeks old) were divided into four groups: 0 mg Zn/kg, 40, 80 mg Zn/kg as Zn-Met, and 80 mg Zn/kg as zinc sulphate (ZnSO4). Eggshell quality, Zn contents, Zn-containing enzyme activities and expressions of shell matrix proteins in eggshell gland (ESG) were analysed. Zn-Met treatment at 80 mg/kg increased (P < 0·05) egg weight and eggshell strength throughout the experiments. The 80 mg/kg Zn-Met group (P < 0·05) had decreased mammillary knob width and larger relative atomic weight percentage of Ca, stronger signal intensity of Ca in linear distribution and the Ca was more evenly distributed in the transversal surface of eggshell. Zn contents (P < 0·001) in yolk and serum, Ca, albumin (Alb) levels in ESG as well as carbonic anhydrase (CA) activity in serum (P < 0·05) and mRNA levels of CA and Ca-binding protein-d28k (CaBP-D28k) (P < 0·001) in the 80 mg/kg Zn-Met group were the highest among all treatments. In conclusion, shell strength as one of eggshell qualities was mostly related to mammillary cone width in ultrastructure caused by the pattern of Ca deposition in eggshell formation. Also, the increase in Zn-Met-induced Ca deposition may be due to the increased Zn contents in serum and tissues, which were attributable to the increased CA concentrations in serum, Ca, Alb levels and up-regulated CA and CaBP-D28k mRNA levels in ESG.

Osteopontin (OPN) is a multifunctional phosphoprotein that is detected in various tissues, including male and female reproductive tracts. In this study, we evaluated OPN expression in mouse oviducts during the estrus cycle, and at days 1–5 of pregnancy and pseudopregnancy by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The mice oocytes, sperm and embryos were treated with different concentrations of anti-OPN antibody in vitro to detect the function of OPN in fertilization and preimplantation embryo development. OPN mRNA and protein expression in mouse oviducts were cyclic dependent throughout the estrous cycle, which was highest at estrous and lowest at diestrous. Such a phenomenon was consistent with the change in estrogen level in mice. The expression levels of OPN in mice oviduct of normal pregnancy and pseudopregnancy were significantly different, which indicated that OPN expression in mouse oviducts was depend on estrogen and preimplantation embryo. Furthermore, anti-OPN antibody treatment could reduce the rates of fertilization, cleavage and blastocyst formation in vitro in a dose-dependent way. Overall, our results indicated that the expression of OPN in mouse oviducts during the estrous cycle and early pregnancy is likely regulated by estrogen and the embryo, and OPN may play a vital role in oocyte fertilization and preimplantation embryo development.

Dermal bone is an important component of the teleost fins, and its ability to regenerate after fin amputation appears to be unlimited. The organic bone matrix contain type I collagen fibers, proteoglycans enriched in chondroitin sulfate, and noncollagenous matrix protein such as osteocalcin, osteopontin, and osteonectin. These molecules are synthesized by fin osteoblasts. Inorganic components chiefly consist of calcium and phosphate that form crystals of hydroxyapatite. Fin rays are described as models to study ossification. Due to this, the identification of the components involved in the synthesis of the organic and inorganic components of lepidotrichial bone are of great interest for the analysis of skeletal disorders in fish ossification. The present study investigates expression of alkaline phosphatase, osteopontin, osteocalcin, and chondroitin sulfate during pectoral fin regeneration in Carassius auratus gibelio. Alkaline phosphatase reaction has been found in the epidermis covering the wound, proximal blastema, near the cells that surround newly-formed lepidotrichia matrix and the tips of regenerating fin rays. Osteopontin has been observed throughout the regeneration blastema but excluded from the scleroblasts lining the inner side of the lepidotrichia. Osteocalcin and chondroitin sulfate expression coincides with the onset of mineralization of lepidotrichial matrix, suggesting its involvement in bone mineralization.

The aim of this study was to evaluate the therapeutic effects of osteopontin neutralization treatment on schistosome-induced liver injury in BALB/C mice. We randomly divided 100 BALB/C mice into groups A, B, C, D and group E. Mice in all groups except group A were abdominally infected with schistosomal cercariae to induce a schistosomal hepatopathological model. Mice in group C, D and group E were respectively administered with praziquantel, praziquantel plus colchicine and praziquantel plus neutralizing osteopontin antibody. We extracted mouse liver tissues at 3 and 9 weeks after the ‘stool-eggs-positive’ day, observed liver histopathological changes by haematoxylin-eosin and Masson trichrome staining and detected the expression of osteopontin, alpha-smooth muscle actin (α-SMA) and transforming growth factor-beta (TGF-β1) by immunohistochemistry, RT-PCR and Western blot. We found that praziquantel plus neutralizing osteopontin antibody treatment significantly decreased the granuloma dimension, the percentage of collagen and the expression of osteopontin, α-SMA and TGF-β1 compared to praziquantel plus colchicine treatment in both the acute and chronic stage of schistosomal liver damage (P<0·05). So we believe that the combined regimen of osteopontin immunoneutralization and anti-helminthic treatment can reduce the granulomatous response and liver fibrosis during the schistosomal hepatopathologic course.

Oral cancer is prevalent worldwide. Studies have indicated that an increase in the osteopontin (OPN) plasma level is correlated with the progression of oral cancer. Our previous report showed that the aqueous garlic extract S-allylcysteine (SAC) inhibited the epithelial–mesenchymal transition (EMT) of human oral cancer CAL-27 cells in vitro. Therefore, the present study investigated whether SAC consumption would help prevent tumour growth and progression, including the EMT, in a mouse xenograft model of oral cancer. The results demonstrated that SAC dose-dependently inhibited the growth of oral cancer in tumour-bearing mice. The histopathological and immunohistochemical staining results indicated that SAC was able to effectively suppress the tumour growth and progression of oral cancer in vivo. The chemopreventive effect of SAC was associated with the suppression of carcinogenesis factors such as N-methylpurine DNA glycosylase and OPN. SAC significantly suppressed the phosphorylation of Akt, mammalian target of rapamycin, inhibitor of κBα and extracellular signal-regulated kinase 1/2 in tumour tissues. The results demonstrated that the SAC-mediated suppression of cyclin D1 protein was associated with an augmented expression of the cell-cycle inhibitor p16Ink4. Furthermore, SAC inhibited the expression of cyclo-oxygenase-2, vimentin and NF-κB p65 (RelA). These results show that SAC has potential as an agent against tumour growth and the progression of oral cancer in a mouse xenograft model.

The ultrastructural study of rare cells within their niche in situ is very difficult. We have developed a method for locating individual transplanted cells and simultaneously identifying and analyzing the molecules and cellular phenotypes surrounding them in situ using transmission electron microscopy. This innovative method involves triple immunogold labeling combined with serial ultrathin sectioning. We demonstrate the validity of this approach by examining the niche of individual transplanted cells from a population highly enriched for hemopoietic stem cells and the ultrastructural expression of two key stem cell regulatory molecules, hyaluronic acid and osteopontin. In addition, we describe the phenotypes of the surrounding cells.

Osteopontin, a glycoprotein, is expressed in several tissues including the mammary gland. The gene has been reported to be associated with milk and its constituents in various livestock species. This gene was sequenced in buffalo and it coded for the protein of 280 amino acids with the conserved GRGDS domain. The sequence was confirmed from the cDNA sequence derived from the mammary gland of buffalo. The earlier-reported 9T/10T variation in the upstream region of the gene was investigated for its effect on milk in buffalo and it was found to be non-significant.

Osteopontin (OPN) is an acidic phosphorylated glycoprotein found in many tissues and physiological fluids. OPN is known to possess multiple biological functions including bone remodeling, cell adhesion, cellular transformation and immunological mediation; these functions have been extensively reviewed (Butler et al. 1996; Sodek et al. 2000).