Bovine seminal plasma (BSP) contains four similar proteins secreted by the seminal vesicles, designated BSP-A1, -A2, -A3, and -30 kDa. These proteins bind to choline phospholipids on the surface of the sperm after ejaculation. These BSP proteins also interact with heparin, apolipoprotein A-I (apoA-I) and apoA-I associated with high-density lipoprotein (HDL). The HDL and heparin present in the female reproductive tract have been implicated in sperm capacitation and the acrosome reaction (AR). This study was undertaken to determine whether or not these BSP proteins and HDL could modulate the capacitation of sperm, and to determine the combined effect of HDL and heparin on capacitation. Washed bovine epididymal sperm were preincubated in buffer containing BSP proteins, washed, and incubated with lipoproteins (HDL, and low- and very low-density lipoproteins) or liposomes with or without apoA-I in the presence or absence of heparin. The percentage of capacitated sperm was evaluated after the AR was induced with lysophosphatidylcholine. HDL alone (160 microg/ml) after an 8-h incubation stimulated the AR of epididymal sperm. The percentage of HDL-enhanced AR further increased when sperm were preincubated with BSP proteins. ApoA-I-liposomes stimulated the AR more rapidly (5 h, 160 microg/ml) than HDL. When sperm were preincubated with BSP proteins, the percentage of apoA-I-enhanced AR further increased. In contrast, when liposomes without apoA-I or when low- or very low-density lipoproteins or lipoprotein-depleted serum was used, no significant increase in the AR was detected with or without BSP proteins. When heparin and HDL or apoA-I-liposomes were used together, their combined effects on the AR were not additive. These results indicate that BSP proteins modulate the process of capacitation induced by heparin, HDL, and apoA-I-liposomes.

Background: The TRIB 1 locus has been linked to hepatic triglyceride metabolism in mice and to plasma triglycerides and coronary artery disease in humans. The lipid‐associated single nucleotide polymorphisms ( SNP s), identified by genome‐wide association studies, are located ≈30 kb downstream from TRIB 1, suggesting complex regulatory effects on genes or pathways relevant to hepatic triglyceride metabolism. The goal of this study was to investigate the functional relationship between common SNP s at the TRIB 1 locus and plasma lipid traits. Methods and Results: Characterization of the risk locus reveals that it encompasses a gene, TRIB1 ‐associated locus ( TRIBAL ), composed of a well‐conserved promoter region and an alternatively spliced transcript. Bioinformatic analysis and resequencing identified a single SNP, rs2001844, within the promoter region that associates with increased plasma triglycerides and reduced high‐density lipoprotein cholesterol and coronary artery disease risk. Further, correction for triglycerides as a covariate indicated that the genome‐wide association studies association is largely dependent on triglycerides. In addition, we show that rs2001844 is an expression trait locus ( eQTL ) for TRIB1 expression in blood and alters TRIBAL promoter activity in a reporter assay model. The TRIBAL transcript has features typical of long noncoding RNAs, including poor sequence conservation. Modulation of TRIBAL expression had limited impact on either TRIB1 or lipid regulatory genes mRNA levels in human hepatocyte models. In contrast, TRIB1 knockdown markedly increased TRIBAL expression in HepG2 cells and primary human hepatocytes. Conclusions: These studies demonstrate an interplay between a novel locus, TRIBAL, and TRIB1 . TRIBAL is located in the genome‐wide association studies identified risk locus, responds to altered expression of TRIB1, harbors a risk SNP that is an eQTL for TRIB1 expression, and associates with plasma triglyceride concentrations.

Objective—: A recent genome-wide association study meta-analysis identified an intronic single nucleotide polymorphism in SMAD3 , rs56062135C>T, the minor allele (T) which associates with protection from coronary artery disease. Relevant to atherosclerosis, SMAD3 is a key contributor to transforming growth factor-β pathway signaling. Here, we seek to identify ≥1 causal coronary artery disease–associated single nucleotide polymorphisms at the SMAD3 locus and characterize mechanisms whereby the risk allele(s) contribute to coronary artery disease risk. Approach and Results—: By genetic and epigenetic fine mapping, we identified a candidate causal single nucleotide polymorphism rs17293632C>T (D′, 0.97; r ² , 0.94 with rs56062135) in intron 1 of SMAD3 with predicted functional effects. We show that the sequence encompassing rs17293632 acts as a strong enhancer in human arterial smooth muscle cells. The common allele (C) preserves an activator protein (AP)-1 site and enhancer function, whereas the protective (T) allele disrupts the AP-1 site and significantly reduces enhancer activity ( P <0.001). Pharmacological inhibition of AP-1 activity upstream demonstrates that this allele-specific enhancer effect is AP-1 dependent ( P T single nucleotide polymorphism represents a novel functional cis-acting element at the SMAD3 locus. The protective (T) allele of rs17293632 disrupts a consensus AP-1 binding site in a SMAD3 intron 1 enhancer, reduces enhancer activity and SMAD3 expression, altering human arterial smooth muscle cell proliferation.

Artemis is a DNA repair factor required for V(D)J recombination, repair of DNA damage induced by ionizing radiation (IR) or radiomimetic drugs, and the maintenance of genome integrity. During V(D)J recombination, Artemis participates in the resolution of hairpin‐sealed coding ends, a step crucial to the constitution of the gene encoding for the antigen receptor of lymphocytes. The precise role of Artemis in the repair of IR‐induced DNA damage remains to be elucidated. Here we show that Artemis is constitutively phosphorylated in cultured cells and undergoes additional phosphorylation events after irradiation. The IR‐induced phosphorylation is mainly, although not solely, dependent on Ataxia‐telangiectasia‐mutated kinase (ATM). The physiological role of these phosphorylation events remains unknown, as in vitro‐generated Artemis mutants, which present impaired IR‐induced phosphorylation, still display an activity sufficient to complement the V(D)J recombination defect and the increased radiosensibility of Artemis‐deficient cells. Thus, Artemis is an effector of DNA repair that can be phosphorylated by ATM, and possibly by DNA‐PKcs and ATR depending upon the type of DNA damage.