Osteopontin phosphopeptide mitigates calcium oxalate stone formation in a Drosophila melanogaster model.

Kidney stone disease affects nearly one in ten individuals and places a significant economic strain on global healthcare systems. Despite the high frequency of stones within the population, effective preventative strategies are lacking and disease prevalence continues to rise. Osteopontin (OPN) is a urinary protein that can inhibit the formation of renal calculi in vitro. However, the efficacy of OPN in vivo has yet to be determined. Using an established Drosophila melanogaster model of calcium oxalate urolithiasis, we demonstrated that a 16-residue synthetic OPN phosphopeptide effectively reduced stone burden in vivo. Oral supplementation with this peptide altered crystal morphology of calcium oxalate monohydrate (COM) in a similar manner to previous in vitro studies, and the presence of the OPN phosphopeptide during COM formation and adhesion significantly reduced crystal attachment to mammalian kidney cells. Altogether, this study is the first to show that an OPN phosphopeptide can directly mitigate calcium oxalate urolithiasis formation in vivo by modulating crystal morphology. These findings suggest that OPN supplementation is a promising therapeutic approach and may be clinically useful in the management of urolithiasis in humans.

Recombinant Osteopontin Improves Neurological Functional Recovery and Protects Against Apoptosis via PI3K/Akt/GSK-3ß Pathway Following Intracerebral Hemorrhage.

BACKGROUND This study aimed to investigate the potential neuroprotective effect of recombinant osteopontin (r-OPN) on apoptotic changes via modulating phosphoinositide-3-kinase/Akt/glycogen synthase kinase 3 beta (PI3K/Akt/GSK-3ß) signaling in a rat model of intracerebral hemorrhage (ICH). MATERIAL AND METHODS We subjected 10-12-week-old Sprague-Dawley male rats (n=120) to injection of autologous blood into the right basal ganglia to induce ICH or sham surgery. ICH animals received vehicle administration, r-OPN (4 µL/pup), or r-OPN combined with phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin (86 ng/pup) at 30 min after injury. Neurological scores and rotarod latencies were evaluated on days 1-5 post-ICH. Brain water content was evaluated on days 1-3 post-ICH. The number of apoptotic cells changes were evaluated by terminal deoxynucleotidyl transferase-mediated 2-deoxyuridine 5-triphosphate-biotin nick-end labeling (TUNEL) and hematoxylin staining. Apoptosis-related proteins Bcl-2, Bax, and cleaved caspase-3 (CC3), and the phosphorylation levels of Akt and GSK-3b were assayed by Western blot. RESULTS Neurological deficits, rotarod latencies, and brain water content following ICH were reduced in the r-OPN group compared to the vehicle group. r-OPN also attenuated cell death in ICH. Furthermore, treatment with r-OPN significantly increased p-Akt expression and decreased p-GSK-3ß. These effects were associated with a decrease in the Bax/Bcl-2 ratio and the suppression of CC3 at 24 h after ICH. Importantly, all the beneficial effects of r-OPN in ICH were abrogated by the PI3K inhibitor wortmannin. CONCLUSIONS r-OPN may provide a wide range of neuroprotection by suppressing apoptosis through the PI3K/Akt/GSK-3ß signaling pathway after ICH.

Growth, Nutrition, and Cytokine Response of Breast-fed Infants and Infants Fed Formula With Added Bovine Osteopontin.

OBJECTIVES: Breast milk contains a high concentration of osteopontin (OPN), a protein having multiple functions. In contrast, infant formula is low in OPN. A randomized clinical trial was performed to evaluate effects of adding a highly enriched bovine OPN fraction to formula, and infants whose mothers had already decided not to breast-feed were recruited. They were fed regular formula (F0) or the same formula with bovine OPN at 65 (F65) or 130 (F130) mg/L (50% and 100% of human milk level, respectively) from 1 to 6 months of age and were compared with a reference group of breast-fed (BF) infants. METHODS: Morbidity was recorded daily and 3-day dietary records collected monthly. Anthropometry was assessed monthly, and blood samples were taken at 1, 4, and 6 months of age. Hematology and iron status, serum cytokines, plasma amino acids, and blood urea nitrogen were analyzed. RESULTS: Formulas were well tolerated and there were no significant differences in formula intake or growth among the formula-fed groups. The F130 group had significantly lower plasma threonine than the F0 and F65 groups, and significantly lower plasma branched-chain amino acids (BCAAs) than the F0 group and, thus, was closer to BF infants. Plasma TNF-α was higher in formula-fed infants than in BF infants. Among the formula-fed groups, the proinflammatory cytokine TNF-α was significantly lower in the F65 and F130 groups than in the F0 group, suggesting that OPN downregulates inflammatory cytokines and thus affects immune function. CONCLUSIONS: Addition of OPN to infant formula changes amino acid metabolism and cytokine responses of FF infants and makes them more similar to BF infants. The lower prevalence of pyrexia in the F130 infants than in F0 infants suggests that adding OPN may confer health benefits.

Urolithiasis: phytotherapy as an adjunct therapy.

Role of herbal drugs and medicinal plant extracts in the successful treatment of urolithiasis, classified as the third most common urinary tract diseases is well documented. Ayurvedic plants and their components mediate antilithogenic effects by altering ionic composition of urine, being diuretic, antioxidant or having antimicrobial activity. Therapeutic peptides and proteins have unique place in pharmaceutical biotechnology due to their critical roles in cell biology. The innovation in antilithiatic proteins is that they are anionic, rich in acidic amino acids which make oxalate unavailable by interacting with calcium and have EF Hand domain which is a characteristic feature of various calcium binding protein like calgranulin, osteopontin. The review provides a background on the pathogenesis of urolithiasis and medical treatments. It focusses on the present research evaluating the scientific basis of antilithiatic potential of various plants and role of plant proteins as therapeutic agents thus opening new vista in the management of urolithiasis. Further investigations are required to fully decipher the mode of action of the potent biomolecules so as to exploit their preventive and therapeutic potential.

Milk osteopontin, a nutritional approach to prevent alcohol-induced liver injury.

Alcohol consumption is a leading cause of liver disease worldwide; thus, there is an urgent need to develop novel therapeutic interventions. Key events for the onset and progression of alcoholic liver disease result in part from the gut-to-liver interaction. Osteopontin is a cytokine present at high concentration in human milk, umbilical cord, and infants' plasma with beneficial potential. We hypothesized that dietary administration of milk osteopontin could prevent alcohol-induced liver injury perhaps by maintaining gut integrity and averting hepatic inflammation and steatosis. Wild-type mice were fed either the control or the ethanol Lieber-DeCarli diets alone or in combination with milk osteopontin for 3 wk, and parameters of gut and liver damage were measured. Milk osteopontin protected the stomach and the gut by increasing gland height, crypt cell plus enterocyte proliferation, and mucin content in addition to lowering macrophages, plasmacytes, lymphocytes, and neutrophils in the mucosa and submucosa in alcohol-fed mice. Milk osteopontin targeted the gut-liver axis, preserving the expression of tight-junction proteins in alcohol-fed mice thus maintaining intestinal integrity and permeability. There was protection from liver injury since transaminases, the activity scores, triglyceride levels, neutrophil infiltration, 3-nitrotyrosine residues, lipid peroxidation end products, translocation of gram-negative bacteria, lipopolysaccharide levels, and tumor necrosis factor-α were lower in cotreated than in ethanol-fed mice. Furthermore, milk osteopontin diminished ethanol-mediated liver injury in OPN knockout mice. Milk osteopontin could be a simple effective nutritional therapeutic strategy to prevent alcohol hepatotoxicity due, among others, to gut protective, anti-inflammatory, and anti-steatotic actions.