Stimulation of Bone Formation in Cortical Bone of Mice Treated with a Receptor Activator of Nuclear Factor-κB Ligand (RANKL)-binding Peptide That Possesses Osteoclastogenesis Inhibitory Activity

To date, parathyroid hormone is the only clinically available bone anabolic drug. The major difficulty in the development of such drugs is the lack of clarification of the mechanisms regulating osteoblast differentiation and bone formation. Here, we report a peptide (W9) known to abrogate osteoclast differentiation in vivo via blocking receptor activator of nuclear factor-κB ligand (RANKL)-RANK signaling that we surprisingly found exhibits a bone anabolic effect in vivo. Subcutaneous administration of W9 three times/day for 5 days significantly augmented bone mineral density in mouse cortical bone. Histomorphometric analysis showed a decrease in osteoclastogenesis in the distal femoral metaphysis and a significant increase in bone formation in the femoral diaphysis. Our findings suggest that W9 exerts bone anabolic activity. To clarify the mechanisms involved in this activity, we investigated the effects of W9 on osteoblast differentiation/mineralization in MC3T3-E1 (E1) cells. W9 markedly increased alkaline phosphatase (a marker enzyme of osteoblasts) activity and mineralization as shown by alizarin red staining. Gene expression of several osteogenesis-related factors was increased in W9-treated E1 cells. Addition of W9 activated p38 MAPK and Smad1/5/8 in E1 cells, and W9 showed osteogenesis stimulatory activity synergistically with BMP-2 in vitro and ectopic bone formation. Knockdown of RANKL expression in E1 cells reduced the effect of W9. Furthermore, W9 showed a weak effect on RANKL-deficient osteoblasts in alkaline phosphatase assay. Taken together, our findings suggest that this peptide may be useful for the treatment of bone diseases, and W9 achieves its bone anabolic activity through RANKL on osteoblasts accompanied by production of several autocrine factors.     

Benzoic acid and specific 2-oxo acids activate hepatic efflux of glutamate at OAT2

The liver is the principal source of glutamate in blood plasma. Recently we have discovered that efflux of glutamate from hepatocytes is catalyzed by the transporter OAT2 (human gene symbol SLC22A7). Organic anion transporter 2 (OAT2) is an integral membrane protein of the sinusoidal membrane domain; it is primarily expressed in liver and much less in kidney, both in rats and humans. Many years ago, Häussinger and coworkers have demonstrated in isolated perfused rat liver that benzoic acid or specific 2-oxo acid analogs of amino acids like e.g. 2-oxo-4-methyl-pentanoate (‘2-oxo-leucine’) strongly stimulate release of glutamate (up to 7-fold); ‘2-oxo-valine’ and the corresponding amino acids were without effect. The molecular mechanism of efflux stimulation has remained unclear. In the present study, OAT2 from human and rat were heterologously expressed in 293 cells. Addition of 1 mmol/l benzoic acid to the external medium increased OAT2-specific efflux of glutamate up to 20-fold; ‘2-oxo-leucine’ was also effective, but not ‘2-oxo-valine’. Similar effects were seen for efflux of radiolabeled orotic acid. Expression of OAT2 did not increase uptake of benzoic acid; thus, benzoic acid is no substrate, and trans-stimulation can be excluded. Instead, further experiments suggest that increased efflux of glutamate is caused by direct interaction of benzoic acid and specific 2-oxo acids with OAT2. We propose that stimulators bind to a distinct extracellular site and thereby accelerate relocation of the empty substrate binding site to the intracellular face. Increased glutamate efflux at OAT2 could be the main benefit of benzoate treatment in patients with urea cycle defects.     

The sulfamide moiety affords higher inhibitory activity and oral bioavailability to a series of coumarin dual selective RAF/MEK inhibitors

Introducing a sulfamide moiety to our coumarin derivatives afforded enhanced Raf/MEK inhibitory activity concomitantly with an acceptable PK profile. Novel sulfamide 17 showed potent HCT116 cell growth inhibition (IC₅₀ = 8 nM) and good PK profile (bioavailability of 51% in mouse), resulting in high in vivo antitumor efficacy in the HCT116 xenograft (ED₅₀ = 4.8 mg/kg). We confirmed the sulfamide moiety showed no negative impact on tests run on the compound to evaluate DMPK (PK profiles in three animal species, CYP inhibition and CYP induction) and the safety profile (hERG and AMES tests). Sulfamide 17 had favorable properties that warranted further preclinical assessment     

Phosphorothioate analogs of sn-2 radyl lysophosphatidic acid (LPA): Metabolically stabilized LPA receptor agonists

We describe an efficient synthesis of metabolically stabilized sn-2 radyl phosphorothioate analogs of lysophosphatidic acid (LPA), and the determination of the agonist activity of each analog for the six LPA receptors (LPA_1–6) using a recently developed TGFα shedding assay. In general, the sn-2 radyl OMPT analogs showed similar agonist activities to the previous 1-oleoyl-2-O-methyl-glycerophosphothioate (sn-1 OMPT) analogs for LPA_1–6 receptors. In most cases, the sn-2 radyl-OMPT analogs were more potent agonists than LPA itself. Most importantly, sn-2 alkyl OMPT analogs were very potent LPA₅ and LPA₆ agonists. The availability of sn-2 radyl OPMT analogs further refines the structure–activity relationships for ligand–receptor interactions for this class of GPCRs.     

Lytic Enzymes toward Aniline-assimilating Rhodococcus erythro-polis AN-13: Purification and Characterization

Three lytic enzymes, C-2, C-4 and C-5, capable of lysing cells of Rhodococcus erythropolis AN-13 were purified from the cultural filtrate of Flavobacterium species SH-548 by (NH₄)₂S0₄ fractionation and column chromatographies on CM-Toyopearl and SP-Sephadex. The three purified enzymes gave single protein bands on polyacrylamide gels. C-4 and C-5 were stable between pH 3.0 and 12.5, and C-2 between pH 5.5 and 11.0. The molecular weights of C-4 and C-5 were 26,000 and that of C-2 was 36,000, as judged on sodium dodecylsulfate-polyacrylamide gel electrophoresis. C-4 and C-5 also showed proteolytic activity toward casein, but C-2 did not exhibit such activity. C-2 showed higher specific lytic activity toward cells of R. erythropolis AN-13 than C-4 and C-5.     

Occurence of a Phosphodiesterase in the Insoluble Fractions from Wheat Seedlings

The volume of carbon dioxide evolved in a shaking apparatus was measured at fixed intervals, and it was confirmed that the fermentation of dry yeast generally depends on three factors and that they are represented with an initial fermenting activity, a power which recovers fermenting activity, and a maximum fermenting activity. This expression of fermenting power was compared with usual expressions and it was proved to be more reasonable, particularly, for deciding the initial fermenting activity.     

Acid-stable α-Amylase of Black Aspergilli

The Acid-stable α-amylase and the acid-unstable α-amylase from Aspergillus niger contained one mole of sulfhydryl group per one mole of enzyme, which probably existed correlating with calcium atom that was essential for the amylase activity.

Iodine reacted at acidic pH specifically with the sulfhydryl group of both enzymes and oxidized it to considerably high degree, since about 4 eq of iodine per mole of sulfhydryl group of both enzymes were consumed. The modification of the sulfhydryl group of the acid-stable α-amylase did not affect the amylase acitvity, while, that of the acid-unstable α-amylase reduced it to 70 per cents intact enzyme. It was difficult to carry out carboxy-methylation of the sulfhydryl group of the acid-stable α-amylase under mild conditions maintaining its activity, but that of the acid-unstable α-amylase was easily achieved.

These facts suggested that some differences existed in the neighborhood of the sulfhydryl group of both enzymes, and that the sulfhydryl group of them was not the active site.     

Identification of Aniline-assimilating Bacteria

Twenty bacterial strains, grown on aniline as a sole source of carbon and nitrogen, and isolated from soil, were identified by morphological and biochemical tests, and cell wall analyses. Eight isolates were Rhodococcus erythropolis (Gray and Thornton) Goodfellow and Alderson, five were Pseudomonas maltophilia Hugh and Ryschenkow and seven were DAB (diaminobutyric acid)-type coryneform bacteria. The Rhodococcus spp. maintained the ability to assimilate aniline, but the pseudomonads and coryneform bacteria readily lost the ability, when grown in the absence of aniline.     

Effects of Dietary Methionine and Cystine on Endogenous Hypercholesterolemia in Hypothyroid Rats

The effects on cholesterolemia of dietary additions (1.2%) of methionine and cystine to a 20% casein diet were studied in both euthyroid and thiouracil-induced hypothyroid rats. The hypothyroid rats lapsed into endogenous hypercholesterolemia, which was due to an increase in the very-low-density lipoprotein plus low-density lipoprotein-cholesterol [(VLDL+LDL)-Ch] concentration with no change in the high-density lipoprotein-cholesterol (HDL-Ch) concentration. These lipoprotein changes in hypothyroid rats resulted in a marked (5-fold) increase in the atherogenic index [AI, (VLDL-LDL)-Ch/HDL-Ch] when compared to that of elutyroid rats. Methionine reduced the hypercholesterolemia in the hypothyroid state by suppressing the elevation in (VLDL + LDL)-Ch with no significant reduction in HDL-Ch, resulting in a notable fall of AI, while methionine showed no significant effect on cholesterolemia and AI in the euthyroid state. Cystine induced hypercholesterolemia due to a significant elevation of HDL-Ch in the euthyroid state, but the amino acid showed no significant effect on cholesterolemia and hence AI in the hypothyroid state. These results suggest that methionine overcomes changes in the parameters involved in Ch biodynamics that cause hypercholesterolemia in the hypothyroid state, whereas cystine counterbalances the parameter changes and results in diminution of its hypercholesterolemic effect in the hypothyroid state.