MRGD, a MAS-related G-protein coupled receptor, promotes tumorigenisis and is highly expressed in lung cancer

To elucidate the function of MAS-related GPCR, member D (MRGD) in cancers, we investigated the in vitro and in vivo oncogenic function of MRGD using murine fibroblast cell line NIH3T3 in which MRGD is stably expressed. The expression pattern of MRGD in clinical samples was also analyzed. We found that overexpression of MRGD in NIH3T3 induced focus formation and multi-cellular spheroid formation, and promoted tumors in nude mice. In other words, overexpression of MRGD in NIH3T3 induced the loss of contact inhibition, anchorage-independent growth and in vivo tumorigenesis. Furthermore, it was found that the ligand of MRGD, beta-alanine, enhanced spheroid formation in MRGD-expressing NIH3T3 cells. From investigation of clinical cancer tissues, we found high expression of MRGD in several lung cancers by immunohistochemistry as well as real time PCR. Based on these results, MRGD could be involved in tumorigenesis and could also be a novel anticancer drug target.     

Visualization of Cortical Projection Neurons with Retrograde TET-Off Lentiviral Vector

We are interested in identifying and characterizing various projection neurons that constitute the neocortical circuit. For this purpose, we developed a novel lentiviral vector that carries the tetracycline transactivator (tTA) and the transgene under the TET Responsive Element promoter (TRE) on a single backbone. By pseudotyping such a vector with modified rabies G-protein, we were able to express palmitoylated-GFP (palGFP) or turboFP635 (RFP) in corticothalamic, corticocortical, and corticopontine neurons of mice. The high-level expression of the transgene achieved by the TET-Off system enabled us to observe characteristic elaboration of neuronal processes for each cell type. At higher magnification, we were able to observe fine structures such as boutons and spines as well. We also injected our retrograde TET-Off vector to the marmoset cortex and proved that it can be used to label the long-distance cortical connectivity of millimeter scale. In conclusion, our novel retrograde tracer provides an attractive option to investigate the morphologies of identified cortical projection neurons of various species.     

ACPA-negative RA consists of two genetically distinct subsets based on RF positivity in Japanese

HLA-DRB1, especially the shared epitope (SE), is strongly associated with rheumatoid arthritis (RA). However, recent studies have shown that SE is at most weakly associated with RA without anti-citrullinated peptide/protein antibody (ACPA). We have recently reported that ACPA-negative RA is associated with specific HLA-DRB1 alleles and diplotypes. Here, we attempted to detect genetically different subsets of ACPA-negative RA by classifying ACPA-negative RA patients into two groups based on their positivity for rheumatoid factor (RF). HLA-DRB1 genotyping data for totally 954 ACPA-negative RA patients and 2,008 healthy individuals in two independent sets were used. HLA-DRB1 allele and diplotype frequencies were compared among the ACPA-negative RF-positive RA patients, ACPA-negative RF-negative RA patients, and controls in each set. Combined results were also analyzed. A similar analysis was performed in 685 ACPA-positive RA patients classified according to their RF positivity. As a result, HLA-DRB1*04:05 and *09:01 showed strong associations with ACPA-negative RF-positive RA in the combined analysis (p = 8.8×10⁻⁶ and 0.0011, OR: 1.57 (1.28–1.91) and 1.37 (1.13–1.65), respectively). We also found that HLA-DR14 and the HLA-DR8 homozygote were associated with ACPA-negative RF-negative RA (p = 0.00022 and 0.00013, OR: 1.52 (1.21–1.89) and 3.08 (1.68–5.64), respectively). These association tendencies were found in each set. On the contrary, we could not detect any significant differences between ACPA-positive RA subsets. As a conclusion, ACPA-negative RA includes two genetically distinct subsets according to RF positivity in Japan, which display different associations with HLA-DRB1. ACPA-negative RF-positive RA is strongly associated with HLA-DRB1*04:05 and *09:01. ACPA-negative RF-negative RA is associated with DR14 and the HLA-DR8 homozygote.     

Aligned genetic linkage maps of apple rootstock cultivar ‘JM7’ and Malus sieboldii ‘Sanashi 63’ constructed with novel EST-SSRs

Identification of markers associated with genes of interest and quantitative trait loci (QTLs), combined with high-density genetic linkage maps, can help reduce labor and costs by enabling marker-assisted selection (MAS). In this study, a dwarfing apple rootstock cultivar ??JM7?? (Malus prunifolia × Malus pumila ??Malling 9??) and wild apple Malus sieboldii ??Sanashi 63?? (section Sorbomalus) were used for constructing genetic linkage maps. Here, a species from section Sorbomalus was used for the first time as a target species in a genome-wide mapping study. We also developed and mapped 137 novel-expressed sequence tag-simple sequence repeat (EST-SSR) markers. The genetic linkage maps of ??JM7?? and ??Sanashi 63?? consisted of 415 and 310 loci and spanned 998.0 and 981.8?cM, respectively, comparable to the reference map of Malus × domestica ??Discovery??. A BLASTN search revealed that all of the EST-SSR sequences used in this study exhibited very high homology to one or more previously characterized apple genome contigs. Although the most homologous contigs of 89 EST-SSRs were located within the same linkage groups (LGs) identified by mapping analysis, the other 48 EST-SSRs were aligned into contigs positioned in different LGs than those identified by mapping. When search criteria were expanded to include the five most homologous contigs of each EST-SSR, at least one of the top five contigs for 15 of these 48 EST-SSRs corresponded to the LG obtained by mapping. The maps of ??JM7?? and ??Sanashi 63?? may be useful for analyzing important rootstock characteristics and identifying markers for MAS.     

Human immunodeficiency virus type 1 Vpr inhibits axonal outgrowth through induction of mitochondrial dysfunction

Human immunodeficiency virus type 1 (HIV-1)-infected macrophages damage mature neurons in the brain, although their effect on neuronal development has not been clarified. In this study, we show that HIV-1-infected macrophages produce factors that impair the development of neuronal precursor cells and that soluble viral protein R (Vpr) is one of the factors that has the ability to suppress axonal growth. Cell biological analysis revealed that extracellularly administered recombinant Vpr (rVpr) clearly accumulated in mitochondria where a Vpr-binding protein adenine nucleotide translocator localizes and also decreased the mitochondrial membrane potential, which led to ATP synthesis. The depletion of ATP synthesis reduced the transportation of mitochondria within neurites. This mitochondrial dysfunction inhibited axonal growth even when the frequency of apoptosis was not significant. We also found that point mutations of arginine (R) residues to alanine (A) residues at positions 73, 77, and 80 rendered rVpr incapable of causing mitochondrial membrane depolarization and axonal growth inhibition. Moreover, the Vpr-induced inhibition was suppressed after treatment with a ubiquinone analogue (ubiquinone-10). Our results suggest that soluble Vpr is a major viral factor that causes a disturbance in neuronal development through the induction of mitochondrial dysfunction. Since ubiquinone-10 protects the neuronal plasticity in vitro, it may be a therapeutic agent that can offer defense against HIV-1-associated neurological disease.     

Hatching enzyme of the ovoviviparous black rockfish Sebastes schlegelii- environmental adaptation of the hatching enzyme and evolutionary aspects of formation of the pseudogene

The hatching enzyme of oviparous euteleostean fishes consists of two metalloproteases: high choriolytic enzyme (HCE) and low choriolytic enzyme (LCE). They cooperatively digest the egg envelope (chorion) at the time of embryo hatching. In the present study, we investigated the hatching of embryos of the ovoviviparous black rockfish Sebastes schlegelii. The chorion-swelling activity, HCE-like activity, was found in the ovarian fluid carrying the embryos immediately before the hatching stage. Two kinds of HCE were partially purified from the fluid, and the relative molecular masses of them matched well with those deduced from two HCE cDNAs, respectively, by MALDI-TOF MS analysis. On the other hand, LCE cDNAs were cloned; however, the ORF was not complete. These results suggest that the hatching enzyme is also present in ovoviviparous fish, but is composed of only HCE, which is different from the situation in other oviparous euteleostean fishes. The expression of the HCE gene was quite weak when compared with that of the other teleostean fishes. Considering that the black rockfish chorion is thin and fragile, such a small amount of enzyme would be enough to digest the chorion. The black rockfish hatching enzyme is considered to be well adapted to the natural hatching environment of black rockfish embryos. In addition, five aberrant spliced LCE cDNAs were cloned. Several nucleotide substitutions were found in the splice site consensus sequences of the LCE gene, suggesting that the products alternatively spliced from the LCE gene are generated by the mutations in intronic regions responsible for splicing.     

Molecular characterization of TRPA1 channel activation by cysteine-reactive inflammatory mediators

TRPA1 is a member of the transient receptor potential (TRP) cation channel family, and is predominantly expressed in nociceptive neurons of dorsal root ganglia (DRG) and trigeminal ganglia. Activation of TRPA1 by environmental irritants such as mustard oil, allicin and acrolein causes acute pain. However, the endogenous ligands that directly activate TRPA1 remain elusive in inflammation. Here, we show that a variety of inflammatory mediators (15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), nitric oxide (NO), hydrogen peroxide (H(2)O(2)), and proton (H(+))) activate human TRPA1 heterologously expressed in HEK cells. These inflammatory mediators induced robust Ca(2+) influx in a subset of mouse DRG neurons. The TRP channel blocker ruthenium red almost completely inhibited neuronal responses by 15d-PGJ(2) and NO, but partially suppressed responses to H(2)O(2) and H(+). Functional characterization of site-directed cysteine mutants of TRPA1 in combination with labeling experiments using biotinylated 15d-PGJ(2) demonstrated that modifications of cytoplasmic N-terminal cysteines (Cys421 and Cys621) were responsible for the activation of TRPA1 by 15d-PGJ(2). In TRPA1 responses to other cysteine-reactive inflammatory mediators, such as NO and H(2)O(2), the extent of impairment by respective cysteine mutations differed from those in TRPA1 responses to 15d-PGJ(2). Interestingly, the Cys421 mutation critically impaired the TRPA1 response to H(+) as well. Our findings suggest that TRPA1 channels are targeted by an array of inflammatory mediators to elicit inflammatory pain in the nervous system.     

Cdc6 determines utilization of p21(WAF1/CIP1)-dependent damage checkpoint in S phase cells

When cells traversing G(1) are irradiated with UV light, two parallel damage checkpoint pathways are activated: Chk1-Cdc25A and p53-p21(WAF1/CIP1), both targeting Cdk2, but the latter inducing a long lasting arrest. In similarly treated S phase-progressing cells, however, only the Cdc25A-dependent checkpoint is active. We have recently found that the p21-dependent checkpoint can be activated and induce a prolonged arrest if S phase cells are damaged with a base-modifying agent, such as methyl methanesulfonate (MMS) and cisplatin. But the mechanistic basis for the differential activation of the p21-dependent checkpoint by different DNA damaging agents is not understood. Here we report that treatment of S phase cells with MMS but not a comparable dose of UV light elicits proteasome-mediated degradation of Cdc6, the assembler of pre-replicative complexes, which allows induced p21 to bind Cdk2, thereby extending inactivation of Cdk2 and S phase arrest. Consistently, enforced expression of Cdc6 largely eliminates the prolonged S phase arrest and Cdk2 inactivation induced with MMS, whereas RNA interference-mediated Cdc6 knockdown not only prolongs such arrest and inactivation but also effectively activates the p21-dependent checkpoint in the UV-irradiated S phase cells.