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Bone formation requires synthesis, secretion, and mineralization of matrix. Deficiencies in these processes produce bone defects. The absence of the PDZ domain protein Na+/H+ exchange regulatory factor 1 (NHERF1) in mice, or its mutation in humans, causes osteomalacia believed to reflect renal phosphate wasting. We show that NHERF1 is expressed by mineralizing osteoblasts and organizes Na+/H+ exchangers (NHEs) and the PTH receptor. NHERF1-null mice display reduced bone formation and wide mineralizing fronts despite elimination of phosphate wasting by dietary supplementation. Bone mass was normal, reflecting coordinated reduction of bone resorption and formation. NHERF1-null bone had decreased strength, consistent with compromised matrix quality. Mesenchymal stem cells from NHERF1-null mice showed limited osteoblast differentiation but enhanced adipocyte differentiation. PTH signaling and Na+/H+ exchange were dysregulated in these cells. Osteoclast differentiation from monocytes was unaffected. Thus, NHERF1 is required for normal osteoblast differentiation and matrix synthesis. In its absence, compensatory mechanisms maintain bone mass, but bone strength is reduced. [ABSTRACT FROM AUTHOR]

We report that multiple symbionts coexist in Dermacentor silva rum. Based on 16S rRNA gene sequence analyses, we prove that Coxiella-llke and Arsenophonus-like symbionts, with 95.6% and 96.7% sequence similarity to symbionts in the closest taxon, respectively, are novel. Moreover, we also provide evidence that the Coxiella-like symbiont appears to be the primary symbiont. [ABSTRACT FROM AUTHOR]

Low estrogen levels undoubtedly underlie menopausal bone thinning. However, rapid and profuse bone loss begins 3 y before the last menstrual period, when serum estrogen is relatively normal. We have shown that the pituitary hormone FSH, the levels of which are high during late perimenopause, directly stimulates bone resorption by osteoclasts. Here, we generated and characterized a polyclonal antibody to a 13-amino-acid-long peptide sequence within the receptor-binding domain of the FSH β-subunit. We show that the FSH antibody binds FSH specifically and blocks its action on osteoclast formation in vitro. When injected into ovariectomized mice, the FSH antibody attenuates bone loss significantly not only by inhibiting bone resorption, but also by stimulating bone formation, a yet uncharacterized action of FSH that we report herein. Mesenchymal cells isolated from mice treated with the FSH antibody show greater osteoblast precursor colony counts, similarly to mesenchymal cells isolated from FSH receptor (FSHR)-/- mice. This suggests that FSH negatively regulates osteoblast number. We confirm that this action is mediated by signaling-efficient FSHRs present on mesenchymal stem cells. Overall, the data prompt the future development of an FSH-blocking agent as a means of uncoupling bone formation and bone resorption to a therapeutic advantage in humans. [ABSTRACT FROM AUTHOR]

Hepatocytes in fatty livers are hypersensitive to apoptosis and undergo escalated apoptotic activity via death receptor–mediated pathways, particularly that of Fas-FasL, causing hepatic injury that can eventually proceed to cirrhosis and end-stage liver disease. Here we report that the hepatocyte growth factor receptor, Met, plays an important part in preventing Fas-mediated apoptosis of hepatocytes by sequestering Fas. We also show that Fas antagonism by Met is abrogated in human fatty liver disease (FLD). Through structure-function studies, we found that a YLGA amino-acid motif located near the extracellular N terminus of the Met α-subunit is necessary and sufficient to specifically bind the extracellular portion of Fas and to act as a potent FasL antagonist and inhibitor of Fas trimerization. Using mouse models of FLD, we show that synthetic YLGA peptide tempers hepatocyte apoptosis and liver damage and therefore has therapeutic potential. [ABSTRACT FROM AUTHOR]

Determines the activation of Wnt/beta-catenin pathway in human colon cancers. Effect of beta-catenin antisense oligodeoxynucleotides on the level of axin2 and human naked cuticle (hnkd) mRNA; Expression of axin2 and hnkd in colon cancer cell lines; Correlation of the increased expression of axin2 and hnkd with truncations in polyposis coli.