Motoki Osawa

Enhanced Expression of Aggrus (T1alpha/Podoplanin), a Platelet-Aggregation-Inducing Factor in Lung Squamous Cell Carcinoma

Aggrus (T1α/podoplanin, known as a specific marker for type I alveolar cells or lymphatic endothelial cells) is a transmembrane sialoglycoprotein that aggregates platelets. Previously, we showed that upregulated expression of Aggrus occurs in colorectal tumors or testicular tumors and could be associated with platelet-aggregating activity and metastatic ability. In testicular tumors, Aggrus is specifically expressed in seminoma. The present study investigates Aggrus expression in human primary lung cancer tissues of different types. Microarray analysis demonstrated that aggrus was significantly expressed in squamous cell carcinoma (10/15; 66.7%). Immunohistochemical analysis also showed that the incidence of positive staining in sections of squamous cell carcinoma (7/8; 87.5%) was higher than that in adenocarcinoma (2/13; 15.4%). Furthermore, Aggrus expression was detected in a squamous cell carcinoma cell line, NCI-H226, by real-time PCR. These findings indicated that overexpression of Aggrus occurred in squamous cell carcinoma of the lung. Therefore, Aggrus could be a useful diagnostic marker for squamous cell carcinoma of the lung.

Aggrus: a diagnostic marker that distinguishes seminoma from embryonal carcinoma in testicular germ cell tumors.

Aggrus (also known as T1α/podoplanin) is a membrane sialoglycoprotein whose function in tumors is unknown. We recently determined that Aggrus possessed the ability of inducing platelet aggregation and that its expression was frequently upregulated in colorectal tumors. Thus, Aggrus expression might be associated with tumor-induced platelet aggregation and tumor metastasis. Here we show, by means of cancer profiling array and real-time PCR, that aggrus mRNA expression is frequently upregulated in testicular germ cell tumors when compared with the surrounding normal tissue. Immunohistochemical staining revealed that Aggrus protein expression was detected in 10 of 11 seminomas (90.9%), but its expression was not observed in embryonal carcinomas (0/4; 0%). Specific markers for seminomas have not been reported, and Aggrus is a potential diagnostic marker for seminomas and may be associated with malignancies of the testis.

A Common Variation in EDAR Is a Genetic Determinant of Shovel-Shaped Incisors

Shovel shape of upper incisors is a common characteristic in Asian and Native American populations but is rare or absent in African and European populations. Like other common dental traits, genetic polymorphisms involved in the tooth shoveling have not yet been clarified. In ectodysplasin A receptor (EDAR), where dysfunctional mutations cause hypohidrotic ectodermal dysplasia, there is a nonsynonymous-derived variant, 1540C (rs3827760), that has a geographic distribution similar to that of the tooth shoveling. This allele has been recently reported to be associated with Asian-specific hair thickness. We aimed to clarify whether EDAR 1540C is also associated with dental morphology. For this purpose, we measured crown diameters and tooth-shoveling grades and analyzed the correlations between the dental traits and EDAR genotypes in two Japanese populations, inhabitants around Tokyo and in Sakishima Islands. The number of EDAR 1540C alleles in an individual was strongly correlated with the tooth-shoveling grade (p = 7.7 x 10(-10)). The effect of the allele was additive and explained 18.9% of the total variance in the shoveling grade, which corresponds to about one-fourth of the heritability of the trait reported previously. For data reduction of individual-level metric data, we applied a principal-component analysis, which yielded PC1-4, corresponding to four patterns of tooth size; this result implies that multiple factors are involved in dental morphology. The 1540C allele also significantly affected PC1 (p = 4.9 x 10(-3)), which denotes overall tooth size, and PC2 (p = 2.6 x 10(-3)), which denotes the ratio of mesiodistal diameter to buccolingual diameter.

Cardiac Ion Channel Gene Mutations in Sudden Infant Death Syndrome

Sudden infant death syndrome (SIDS) is multifactorial and may result from the interaction of a number of environmental, genetic, and developmental factors. We studied three major genes causing long QT syndrome in 42 Japanese SIDS victims and found five mutations, KCNQ1-K598R, KCNH2-T895M, SCN5A-F532C, SCN5A-G1084S, and SCN5A-F1705S, in four cases; one case had both KCNH2-T895M and SCN5A-G1084S. All mutations were novel except for SCN5A-F532C, which was previously detected in an arrhythmic patient. Heterologous expression study revealed significant changes in channel properties of KCNH2-T895M, SCN5A-G1084S, and SCN5A-F1705S, but did not in KCNQ1-K598R and SCN5A-F532C. Our data suggests that nearly 10% of SIDS victims in Japan have mutations of the cardiac ion channel genes similar to in other countries.

Association of plasma triglyceride-rich lipoprotein remnants with coronary atherosclerosis in cases of sudden cardiac death

Among the risk factors for coronary atherosclerosis, elevated LDL-C level is best known. The action of lipoprotein lipase on triglyceride-rich lipoproteins produces remnant lipoprotein particles enriched in cholesterol and apolipoprotein E (apo E). Apo E serves as the ligand for uptake of remnant lipoproteins via the LDL-receptor or the remnant receptor. In this study, postmortem plasma total cholesterol, triglycerides (TG), VLDL-C, HDL-C, lipoprotein (a) [Lp(a)] and remnant-like lipoprotein particles (RLP)-cholesterol, RLP-TG, apolipoproteins B, C III and E were measured, together with LDL-C to assess their potential contribution to the severity of coronary and aortic atherosclerosis of the 197 cases of sudden death (132 cardiac death and 65 non-cardiac death). In all cases, the severity of coronary atherosclerosis was determined at postmortem pathological examination. RLP-cholesterol (RLP-C) and LDL-C concentrations were significantly higher in cases with advanced coronary atherosclerosis compared with those without coronary atherosclerosis; respective median values were 13.5 vs 8.4 mg/dl (P < 0.001) and 140 vs 115 mg/dl (P < 0.05). RLP-C levels were more strongly correlated with the severity score of coronary atherosclerosis than LDL-C.

A novel β(1,6)-N-acetylglucosaminyltransferase V (GnT-VB)1

UDP‐N‐acetylglucosamine:α(1,6)‐D‐mannoside β(1,6)‐N‐acetylglucosaminyltransferase (GnT‐V, Mgat5) functions in the biosynthesis of N‐linked glycans and is transcriptionally upregulated by oncogene signaling. We report here the cloning and characterization of a human cDNA encoding a distinct enzyme with related substrate specificity, termed GnT‐VB, which is predicted to have 53% similarity to the original amino acid sequence of GnT‐V(A). Transient expression of GnT‐VB cDNA in COS7 cells yielded significant increases of activity toward GnT‐VA acceptors, including synthetic saccharides and N‐linked glycopeptides, with some differences in specificity. Unlike GnT‐VA, GnT‐VB required divalent cation for full activity. EST databases showed expression of a 6 bp (+) splice isoform of GnT‐VB; when expressed, this enzyme showed significantly reduced activity. CHO Lec4 cells, which do not express GnT‐VA or B activity, lack synthesis of the N‐linked β(1,6) branch, and do not bind L‐phytohemagglutinin (L‐PHA), were transfected with GnT‐VB or GnT‐VA; both then bound significant amounts of L‐PHA, demonstrating that both enzymes synthesized N‐linked β(1,6) branched glycans in vivo. Real‐time polymerase chain reaction results showed that GnT‐VB mRNA was highly expressed in brain and testis, with lesser levels in other tissues, while human GnT‐VA showed a more general expression, but with low levels in brain and no expression in skeletal muscle.

Association of α2-HS glycoprotein (AHSG, fetuin-A) polymorphism with AHSG and phosphate serum levels

Alpha2-HS glycoprotein (AHSG), also known as fetuin-A, is a plasma protein displaying high-affinity interaction with calcium phosphate, by which ectopic vascular calcification is prevented. This investigation has attempted to evaluate the relationship between AHSG polymorphism and serum levels of AHSG and calcium-related parameters. AHSG levels in unrelated individuals were measured by quantitative rocket immunoelectrophoresis and were 581±38, 542±31, and 494±23mg/l for three major genotypes of AHSG1 homozygotes (n=99), heterozygotes (n=55), and AHSG2 homozygotes (n=22), respectively (differences were significant: P<0.001). The circulating AHSG level was therefore influenced by the genetic polymorphism with the additive reduction in the AHSG2 allele. Statistical analysis of simple and multiple regression models revealed no associations between AHSG levels and serum values of total calcium, albumin-corrected total calcium, and ionized calcium. However, the AHSG levels demonstrated a significant negative correlation with free phosphate levels (P<0.001), indicating that AHSG is a novel determinant of serum phosphate. The AHSG polymorphism is attributable to the hereditary variation of AHSG and phosphate serum levels, which may affect skeletal development and chronic disorders such as vascular calcification.

Stature estimation formulae from radiographically determined limb bone length in a modern Japanese population

The objective of this study was to derive regression formulae for stature estimation from long limb bones in a Japanese population. Moreover, commonly employed estimation equations, such as that of Fujii, were re-evaluated through application of current data. To construct equations, measurements were conducted on 434 living subjects (342 females and 92 males; 18-59years old). The whole or maximum length of the femur, tibia, and humerus was determined radiographically using dual-energy X-ray absorptiometry, which permitted measurement of long bones with no magnification. Regression formulae were constructed for females and males relative to the real body height measured in the erect position. Lower limbs of the femur and tibia were more accurate predictors (R=0.813-0.903) than the humerus was (R=0.670-0.708). Multiple regression models were produced for all three bones and the two leg bones, revealing no significant difference between R values. Comparison of these equations with those of earlier studies of Andou and Fujii verified differences in estimated stature, indicating that stature estimation formulae should be constructed based on current data obtained from precise physical measurements. These equations will benefit forensic anthropology and nutrition science for stature estimation of contemporary Japanese individuals.

The possible role of remnant-like particles as a risk factor for sudden cardiac death.

Abstract Postmortem plasma lipid and lipoprotein levels were analyzed in two groups of Japanese subjects who died suddenly and unexpectedly due to cardiac (n = 93) or non-cardiac (n = 26) causes. No individuals in either group had a significant medical or cardiac history. In this study, we measured plasma total cholesterol, triglycerides, VLDL-cholesterol, LDL-cholesterol, HDL-cholesterol, and especially triglyceride-rich lipoprotein remnants. Triglyceride and apo E-rich remnant-like particles (RLP) were studied as a possible risk factor for sudden cardiac death in relation to the progression of coronary atherosclerosis. The receiver-operating characteristic curve (ROC) analysis showed that RLP-TG was the most significant risk factor for sudden cardiac death among the lipids and lipoproteins and RLP-C was the best predictor for coronary atherosclerosis. HDL-C and LDL-C levels were within normal limits in the majority of the cases and did not appear to relate to the sudden cardiac death. Apo E phenotyping was performed for the detection of the genetic background in the lipid metabolism. The frequency of the Apo E3/3 (wild type) phenotype, which closely relates with the remnant metabolism, was significantly reduced in the sudden cardiac death group. Our study on the postmortem plasma lipid analysis suggested that RLP-C and RLP-TG are the best risk predictor for coronary atherosclerosis and sudden cardiac death, respectively.

Gene Flow and Natural Selection in Oceanic Human Populations Inferred from Genome-Wide SNP Typing

It is suggested that the major prehistoric human colonizations of Oceania occurred twice, namely, about 50,000 and 4,000 years ago. The first settlers are considered as ancestors of indigenous people in New Guinea and Australia. The second settlers are Austronesian-speaking people who dispersed by voyaging in the Pacific Ocean. In this study, we performed genome-wide single-nucleotide polymorphism (SNP) typing on an indigenous Melanesian (Papuan) population, Gidra, and a Polynesian population, Tongans, by using the Affymetrix 500K assay. The SNP data were analyzed together with the data of the HapMap samples provided by Affymetrix. In agreement with previous studies, our phylogenetic analysis indicated that indigenous Melanesians are genetically closer to Asians than to Africans and European Americans. Population structure analyses revealed that the Tongan population is genetically originated from Asians at 70% and indigenous Melanesians at 30%, which thus supports the so-called Slow train model. We also applied the SNP data to genome-wide scans for positive selection by examining haplotypic variation and identified many candidates of locally selected genes. Providing a clue to understand human adaptation to environments, our approach based on evolutionary genetics must contribute to revealing unknown gene functions as well as functional differences between alleles. Conversely, this approach can also shed some light onto the invisible phenotypic differences between populations.