Unique insertion/deletion polymorphisms within histidine-rich region of histidine-rich glycoprotein in Thoroughbred horses.

Histidine-rich glycoprotein (HRG) is abundant plasma protein with various effects on angiogenesis, coagulation, and immune responses. Previously, we identified the base and amino acid sequences of equine HRG (eHRG) and revealed that eHRG regulates neutrophil functions. In this study, we first conducted a large-scale gene analysis with DNA samples extracted from 1700 Thoroughbred horses and identified unique insertion/deletion polymorphisms in the histidine-rich region (HRR) of eHRG. Here we report two types of polymorphisms (deletion type 1 [D1] and deletion type 2 [D2]) containing either a 45 bp or 90 bp deletion in the HRR of eHRG, and five genotypes of eHRG (insertion/insertion [II], ID1, ID2, D1D1, and D1D2) in Thoroughbred horses. Allele frequency of I, D1, and D2, was 0.483, 0.480, and 0.037 and the incidence of each genotype was II: 23.4%, ID1: 46.2%, ID2: 3.6%, D1D1: 23.1%, and D1D2: 3.7%, respectively. The molecular weights of each plasma eHRG protein collected from horses with each genotype was detected as bands of different molecular size, which corresponded to the estimated amino acid sequence. The nickel-binding affinity of the D1 or D2 deletion eHRG was reduced, indicating a loss of function at the site. eHRG proteins show a variety of biological and immunological activities in vivo, and HRR is its active center, suggesting that genetic polymorphisms in eHRG may be involved in the performance in athletic ability, productivity, and susceptibility to infectious diseases in Thoroughbred horses.

Histidine-Rich Glycoprotein Functions as a Dual Regulator of Neutrophil Activity in Horses.

Histidine-rich glycoprotein (HRG) is an abundant plasma protein that has been identified in most mammals. We first identified whole genome sequence of equine HRG (eHRG) and succeeded to purify eHRG from plasma of horses. Since HRG interacts with various ligands, this protein is thought to be involved in immune response, coagulation, and angiogenesis. Systemic inflammatory response syndrome (SIRS) is characterized as a non-specific, clinical, pro-inflammatory immune response that damage organs and tissues in the host. Recent reports revealed that blood HRG levels in human patients with SIRS are approximately 50% lower than those in healthy controls, indicating the use of HRG as a biomarker or treatment for SIRS. SIRS is also a serious issue in equine medicine. In this study, we investigated various effects of eHRG on neutrophil functions, including adhesion, migration, phagocytosis, reactive oxygen species (ROS) production, and lysosome maturation using neutrophils isolated from horses. Microscopic observation showed that the addition of eHRG to the culture diminished adhesion of neutrophils stimulated with LPS. Using the Boyden chamber technique, we showed that eHRG reduced neutrophil chemotaxis induced by recombinant human IL-8. Luminol-dependent chemiluminescence assay demonstrated that eHRG restrained the peak of LPS-promoted ROS production from neutrophils. In contrast, eHRG promoted phagocytic activity evaluated with uptake of fluorescent dye conjugated particles, as well as lysosomal maturation assessed using fluorescent staining for lysosomes of equine neutrophils. These results indicated that eHRG acts as a dual regulator of neutrophils in horses.

Anthropogenic and natural organohalogen compounds in melon-headed whales (Peponocephala electra) stranded along the Japanese coastal waters: Temporal trend analysis using archived samples in the environmental specimen bank (es-BANK).

The present study determined recent accumulation levels of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), polychlorinated diphenyl ethers (PCDEs), methoxylated-PBDEs (MeO-PBDEs) and 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1) in the blubber of melon-headed whales (Peponocephala electra) stranded along the Japanese coastal waters in 2015 and examined temporal trends of these organohalogen compound (OHC) levels by analyzing blubber samples of this species archived in the environmental specimen bank which were collected in 1982, 2001, 2002, 2006, 2010 and 2011. The median concentrations in melon-headed whales stranded recently were in the order of DDTs ≈ PCBs > HBCDDs > Q1 > CHLs > MeO-PBDEs > PBDEs > HCB > HCHs > PCDEs, indicating that considerable amounts of HBCDDs, in addition to DDTs and PCBs, have been transported to tropical and subtropical waters of the open ocean and pelagic whale species might be exposed to relatively high levels of these OHCs. Temporal trend analyses of OHC levels in the blubber of melon-headed whales revealed significant decrease for anthropogenic OCs such as DDTs, PCBs, HCB, HCHs and PCDEs, and significant increase for CHLs, PBDEs, HBCDDs, MeO-PBDEs and Q1 since 1982. Besides, the analyses from 2001 to 2015 showed no decreasing trends (unchanged) for some PCB congeners, p,p'-DDE, cis- and trans-nonachlors, Q1, BDE-47, -100 and -154, and significantly increasing trends for α-HBCDD and 6MeO-BDE47, suggesting their chronic exposure for this pelagic whale species.