The present studies were undertaken to determine the effect of dietary salt intake on the renal expression of cyclooxygenase-1 (COX-1) and -2 (COX-2). Protein levels were assessed by Western blotting, and mRNA expression was assessed by reverse transcription-polymerase chain reaction (RT-PCR) on cDNA prepared from kidney regions, dissected nephron segments, and cultured renal cells. Both isoforms were expressed at high levels in inner medulla (IM), with low levels detected in outer medulla and cortex. COX-1 mRNA was present in the glomerulus and all along the collecting duct, whereas COX-2 mRNA was restricted to the macula densa-containing segment (MD), cortical thick ascending limb (CTAL), and, at significantly lower levels, in the inner medullary collecting duct. Both isoforms were highly expressed at high levels in cultured medullary interstitial cells and at lower levels in primary mesangial cells and collecting duct cell lines. Maintaining rats on a low- or high-NaCl diet for 1 wk did not affect expression of COX-1. In IM of rats treated with a high-salt diet, COX-2 mRNA increased 4.5-fold, and protein levels increased 9.5-fold. In contrast, cortical COX-2 mRNA levels decreased 2.9-fold in rats on a high-salt diet and increased 3.3-fold in rats on a low-salt diet. A low-salt diet increased COX-2 mRNA 7.7-fold in MD and 3.3-fold in CTAL. Divergent regulation of COX-2 in cortex and medulla by dietary salt suggests that prostaglandins in different kidney regions serve different functions, with medullary production playing a role in promoting the excretion of salt and water in volume overload, whereas cortical prostaglandins may protect glomerular circulation in volume depletion.

Summary The Insulin/IGF signaling pathway (IIS) is a prominent regulator of aging of worms, flies, mice and likely humans. Delayed aging by IIS reduction protects the nematode, C. elegans, from toxicity associated with the aggregation of the Alzheimer's disease linked human peptide, Aβ. We reduced IGF signaling in Alzheimer's model mice and discovered that these animals are protected from the Alzheimer's-like disease symptoms including reduced behavioral impairment, neruoinflammation, neuronal and synpatic loss. This protection is correlated with the hyper-aggregation of Aβ leading to tightly packed, ordered plaques suggesting that one aspect of the protection conferred by reduced IGF signaling is the possible sequestration of soluble Aβ oligomers into dense aggregates of lower toxicity. These findings indicate that the IGF signaling regulated mechanism that protects from Aβ toxicity is conserved from worms to mammals and point to the modulation of this signaling pathway as a promising strategy for the development of Alzheimer's disease therapy.

Vitamin K 2 is a critical nutrient required for blood clotting that also plays an important role in bone formation. Vitamin K 2 supplementation up-regulates the expression of bone markers, increases bone density in vivo, and is used clinically in the management of osteoporosis. The mechanism of vitamin K 2 action in bone formation was thought to involve its normal role as an essential cofactor for ␥-carboxylation of bone matrix proteins. However, there is evidence that suggests vitamin K 2 also has a transcriptional regulatory function. Vitamin K 2 bound to and activated the orphan nuclear receptor SXR and induced expression of the SXR target gene, CYP3A4, identifying it as a bona fide SXR ligand. Vitamin K 2 treatment of osteosarcoma cells increased mRNA levels for the osteoblast markers bone alkaline phosphatase, osteoprotegerin, osteopontin, and matrix Gla protein. The known SXR activators rifampicin and hyperforin induced this panel of bone markers to an extent similar to vitamin K 2 . Vitamin K 2 was able to induce bone markers in primary osteocytes isolated from wild-type murine calvaria but not in cells isolated from mice deficient in the SXR ortholog PXR. We infer that vitamin K 2 is a transcriptional regulator of bonespecific genes that acts through SXR to favor the expression of osteoblastic markers. Thus, SXR has a novel role as a mediator of bone homeostasis in addition to its role as a xenobiotic sensor. An important implication of this work is that a subset of SXR activators may function as effective therapeutic agents for the management of osteoporosis.

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We have evaluated a diagnostic system based on the loop-mediated isothermal amplification (LAMP) assay for the rapid, simple, and sensitive detection of Newcastle disease virus (NDV) directly from culture isolates as well as clinical samples. By using one set of specific primers targeting the fusion protein gene, the LAMP assay rapidly amplified the target gene within 2 h, requiring only a regular laboratory water bath or heat block for reaction. The results obtained from testing the genomes of 38 NDV strains, other different viruses, and clinical samples of experimentally infected chickens showed that LAMP was as sensitive and specific as nested PCR. All LAMP-positive samples were positive by nested PCR. The LAMP assay is faster than nested PCR, cost-effective, and easy to perform. Our results clearly demonstrate that the LAMP-based assay is a useful tool for the rapid and sensitive diagnosis of NDV infection.