18F-labeled flavones for in vivo imaging of β-amyloid plaques in Alzheimer’s brains

In vivo imaging of β-amyloid (Aβ) aggregates in the brain may lead to early detection of Alzheimer’s disease (AD) and monitoring of the progression and effectiveness of treatment. The purpose of this study was to develop novel ¹⁸F-labeled amyloid-imaging probes based on flavones as a core structure. Fluoropegylated (FPEG) flavone derivatives were designed and synthesized. The affinity of the derivatives for Aβ aggregates varied from 5 to 321 nM. In brain sections of AD model mice, FPEG flavones with the dimethylamino group intensely stained β-amyloid plaques. In biodistrubution experiments using normal mice, they displayed high uptake in the brain ranging from 2.9 to 4.2%ID/g at 2 min postinjection. The radioactivity washed out from the brain rapidly (1.3–2.0%ID/g at 30 min), which is highly desirable for β-amyloid imaging agents. FPEG flavones may be potential PET imaging agents for β-amyloid plaques in Alzheimer’s brains.     

Distribution of a novel protein AgK114 expression in the normal tissues of adult mice: dual expression of AgK114 and growth hormone in anterior pituitary cells

The novel antigen K114 (AgK114) has been previously identified in normal hamster skin, and its expression has been up-regulated accompanying tissue damages of the skin, although there is no information on its biological functions. To determine the physiological role of AgK114, we prepared anti-mouse AgK114 monoclonal antibody and studied its tissue distribution in healthy adult mice by immunocytochemistry. A widespread and unique expression of AgK114 peptide was found in the selected organs of various systems (hair follicle cells and sebaceous gland of skin, ciliated epithelial cells of trachea and bronchial tube, striated portion of submandibular gland, distal convoluted tubule cells of kidney, ciliated epithelial cells of oviduct, medulla of adrenal gland and anterior lobe of pituitary gland). Interestingly, dual expression of AgK114 peptide and growth hormone in somatotrophs was found in anterior lobe of pituitary gland by double immunocytochemistry. AgK114 peptide was expressed widely in many regionally well-defined cellular systems in various peripheral tissues, suggesting that AgK114 peptide may have some roles of physiological functions in these organs. The data from our current study have provided a rationale for further studies of functional roles of AgK114 peptide in a variety of organs or tissues under physiological conditions.     

The molecular scaffold Gab2 is a crucial component of RANK signaling and osteoclastogenesis

Morphogenesis and remodeling of bone involve synthesis of bone matrix by osteoblasts and coordinate resorption of bone by osteoclasts. Defective bone remodeling caused by altered osteoclast activity underlies a multitude of osteopenic disorders. Receptor activator of NF-kappaB (RANK) and its ligand RANKL have been identified as essential factors involved in osteoclast development and bone remodeling, but their mechanism and interacting factors have not been fully characterized. Here we report that the molecular adapter Grb-2-associated binder-2 (Gab2) associates with RANK and mediates RANK-induced activation of NF-kappaB, Akt and Jnk. Inactivation of the gene encoding Gab2 in mice results in osteopetrosis and decreased bone resorption as a result of defective osteoclast differentiation. We also show that Gab2 has a crucial role in the differentiation of human progenitor cells into osteoclasts. We have thus identified a new, key regulatory scaffold molecule, Gab2, that controls select RANK signaling pathways and is essential for osteoclastogenesis and bone homeostasis.     

Development of Microsatellite Markers for Japanese Scallop (Mizuhopecten yessoensis) and Their Application to a Population Genetic Study

Abstract The Japanese scallop (Mizuhopecten yessoensis) is one of the main fishery products in Japan, but with the expansion of culture operations of the Japanese scallop, various problems have been encountered including high mortality, poor growth, poor seed production, and so on. Moreover, there is concern that many years of cultivation may have affected the genetic structure of the scallop population. To approach these problems and concerns, we developed microsatellite markers as a molecular tool for population genetic studies. By using 4 microsatellite markers as well as a mitochondrial marker, we investigated the genetic structure of samples from the islands of Hokkaido (14 populations) and Honshu (Tohoku, 3 populations) in Japan, and south Primorye (4 populations) in Russia. All the populations sampled had high genetic diversity (average expected heterozygosity, 0.7011 to 0.7622; haplotype diversity, 0.6090 to 0.8848), and almost all showed a tendency of homozygote excess, which was significant in 2 populations. Hierarchical analysis of molecular variance tests based on the microsatellite and mitochondrial markers indicated that the 3 geographic regions were genetically divergent from one another, with little evidence of divergence within regions. Homogeneity in allele frequency distributions between natural and cultured scallops and allele frequency stability over a period of 2 decades indicated that the culturing operations have probably not had a substantial effect on the genetic structure of the populations.     

Suppression of MMP-9 by doxycycline in brain arteriovenous malformations

Background  

The primary aim of this study is to demonstrate the feasibility of utilizing doxycycline to suppress matrix metalloproteinase-9 (MMP-9) in brain arteriovenous malformations (AVMs).     

Cellular quality control screening to identify amino acid pairs for substituting the disulfide bonds in immunoglobulin fold domains

We are interested in determining which amino acid pairs can be substituted for the disulfide (S-S) bonds in proteins without disrupting their native structures under physiological conditions. In this study, we focused on the intradomain S-S bonds in Ig fold domains and aimed to determine a simple rule for replacement of their S-S bonds. The cysteines of four different Ig fold domains were mutated randomly, and the amino acid pairs substituted for the S-S bonds were screened by the method utilizing a cellular quality control system. Among the 36 selected mutants, 31 were natively folded without S-S bonds, as judged from the cooperativity of thermal unfolding. In addition, the selected mutant llama heavy chain antibodies retained antigen-binding affinity. At least two of the pairs Ala:Ala, Ala:Val, Val: Ala, and Val:Val were found in the selected mutants for all four different Ig fold domains, and they were stably folded at 30 degrees C. This suggests that examination of these four pairs could be enough to obtain natively folded Ig fold domains without S-S bonds.     

Plasmacytoid dendritic cells regulate Th cell responses through OX40 ligand and type I IFNs

Dendritic cells (DCs) show a functional plasticity in determining Th responses depending on their maturational stage or on maturational signals delivered to the DCs. Human plasmacytoid DCs (PDCs) can induce either Th1- or Th2-type immune responses upon exposure to viruses or IL-3, respectively. In this study we have investigated the Th-polarizing capacity of PDCs after short (24-h) or long (72-h) culture with stimuli and have assessed the expression and function of OX40 ligand (OX40L) in PDC-mediated Th polarization in addition to type I IFN-dependent responses. IL-3-treated PDCs expressed OX40L, but produced almost no IFN-alpha in response to T cell stimulation (CD40 ligand or T cell interaction), resulting in the preferential priming of Th2 cells through OX40L-dependent mechanisms. Meanwhile, PDCs were rapidly endowed by viral infection (Sendai virus) with a high potency to develop IFN-gamma-producing Th cells depending on their capacity to residually produce IFN-alpha. Although Sendai virus-stimulated PDCs simultaneously expressed OX40L in their maturational process, the Th1-inducing effect of endogenous type I IFNs may overcome and thus conceal the OX40L-dependent Th2 responses. However, during maturation in response to Sendai virus over the longer 72-h period, the expression level of OX40L was up-regulated, whereas the residual IFN-alpha-producing ability was down-regulated, and consequently, the PDCs with prolonged Sendai virus stimulation induced Th2 responses to some extent. Thus, PDCs have the distinct means to dictate an appropriate response to environmental stimuli.