GPCR Screening Reveals that the Metabolite Receptor HCAR3 Regulates Epithelial Proliferation, Migration, and Cellular Respiration.

Epithelial cells in the skin and other tissues rely on signals from their environment to maintain homeostasis and respond to injury, and GPCRs play a critical role in this communication. A better understanding of the GPCRs expressed in epithelial cells will contribute to understanding the relationship between cells and their niche and could lead to developing new therapies to modulate cell fate. This study used human primary keratinocytes as a model to investigate the specific GPCRs regulating epithelial cell proliferation and differentiation. We identified 3 key receptors-HCAR3, LTB4R, and GPR137-and found that knockdown of these receptors led to changes in numerous gene networks that are important for maintaining cell identity and promoting proliferation while inhibiting differentiation. Our study also revealed that the metabolite receptor HCAR3 regulates keratinocyte migration and cellular metabolism. Knockdown of HCAR3 led to reduced keratinocyte migration and respiration, which could be attributed to altered metabolite use and aberrant mitochondrial morphology caused by the absence of the receptor. This study contributes to understanding the complex interplay between GPCR signaling and epithelial cell fate decisions.

Location matters: cellular heterogeneity in the hepatic lobule and hepatocellular carcinoma.

Tumor heterogeneity is a hallmark of cancer but a challenging problem to dissect mechanistically. Less recognized is that cells within normal tissues are also remarkably diverse. Hepatocytes are a great example because their spatial positioning and the local microenvironment govern their genetic heterogeneity. Recent studies show that primary liver tumors display heterogeneity similar to that observed in the normal tissue providing clues to the cellular precursor of the tumor and how variations in the lobule microenvironment support tumor formation and aggressiveness. Identifying the principles that control cellular diversity in a healthy liver may highlight potential mechanisms driving hepatic tumor heterogeneity.

Arginine metabolism regulates human erythroid differentiation through hypusination of eIF5A.

Metabolic programs contribute to hematopoietic stem and progenitor cell (HSPC) fate, but it is not known whether the metabolic regulation of protein synthesis controls HSPC differentiation. Here, we show that SLC7A1/cationic amino acid transporter 1-dependent arginine uptake and its catabolism to the polyamine spermidine control human erythroid specification of HSPCs via the activation of the eukaryotic translation initiation factor 5A (eIF5A). eIF5A activity is dependent on its hypusination, a posttranslational modification resulting from the conjugation of the aminobutyl moiety of spermidine to lysine. Notably, attenuation of hypusine synthesis in erythroid progenitors, by the inhibition of deoxyhypusine synthase, abrogates erythropoiesis but not myeloid cell differentiation. Proteomic profiling reveals mitochondrial translation to be a critical target of hypusinated eIF5A, and accordingly, progenitors with decreased hypusine activity exhibit diminished oxidative phosphorylation. This affected pathway is critical for eIF5A-regulated erythropoiesis, as interventions augmenting mitochondrial function partially rescue human erythropoiesis under conditions of attenuated hypusination. Levels of mitochondrial ribosomal proteins (RPs) were especially sensitive to the loss of hypusine, and we find that the ineffective erythropoiesis linked to haploinsufficiency of RPS14 in chromosome 5q deletions in myelodysplastic syndrome is associated with a diminished pool of hypusinated eIF5A. Moreover, patients with RPL11-haploinsufficient Diamond-Blackfan anemia as well as CD34+ progenitors with downregulated RPL11 exhibit a markedly decreased hypusination in erythroid progenitors, concomitant with a loss of mitochondrial metabolism. Thus, eIF5A-dependent protein synthesis regulates human erythropoiesis, and our data reveal a novel role for RPs in controlling eIF5A hypusination in HSPCs, synchronizing mitochondrial metabolism with erythroid differentiation.

Effects of ß-glucan with vitamin E supplementation on the physiological response, litter performance, blood profiles, immune response, and milk composition of lactating sows.

OBJECTIVE: This study was conducted to evaluate the effects of ß-glucan with vitamin E supplementation on the physiological response, litter performance, blood profiles, immune response, and milk composition of lactating sows. METHODS: A total of 50 multiparous F1 sows (Yorkshire×Landrace) with an average body weight (BW) of 233.6±4.30 kg and an average parity of 4.00±0.307 and their litters were used in this experiment. All sows were allotted to one of five treatments, taking into consideration BW, backfat thickness, and parity in a completely randomized design with 10 replicates. The experimental diets included a corn-soybean meal-based basal diet with or without 0.1% or 0.2% ß-glucan and 110 IU vitamin E/kg diet. RESULTS: All treatments added with ß-glucan or vitamin E were statistically higher in the average daily feed intake (ADFI) of lactating sows compared to those of the control (Diet, p<0.01). Additionally, the ADFI of lactating sows was significantly higher in the groups supplemented with 0.1% ß-glucan compared to 0.2% ß-glucan (BG, p<0.01). There was an increasing trend in piglet weight at weaning (BG, p = 0.07), litter weight at the 21st day of lactation (BG, p = 0.07) and litter weight gain (BG, p = 0.08) in groups supplemented with 0.1% ß-glucan. The addition of 110 IU vitamin E/kg diet increased vitamin E concentration significantly in lactating sows (VE, p<0.01) and exhibited a trend for higher concentrations of vitamin E (VE, p = 0.09) in piglets. Adding 0.1% ß-glucan compared to 0.2% ß-glucan induced a decrease in the concentration of tumor necrosis factor-α in lactating sows (BG, p = 0.06) and in piglets (BG, p = 0.09) on the 21st day of lactation. There were no significant differences in the milk composition of sows. CONCLUSION: Adding 0.1% ß-glucan and 110 IU vitamin E/kg to a lactating sow's diet was beneficial to the growth performance of piglets by leading to an increase in the feed intake of sows and efficiently supplying vitamin E to both the sows and piglets.

15-Hydroxyprostaglandin dehydrogenase inhibitor prevents contrast-induced acute kidney injury.

The two primary mechanisms by which iodinated contrast media (CM) causes contrast-induced acute kidney injury (CIAKI) are the hemodynamic effect causing intrarenal vasoconstriction and the tubular toxic effect causing acute tubular necrosis. Inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), which degrades prostaglandin E2 (PGE2), promotes tissue repair and regeneration in many organs. PGE2 causes intrarenal arterial vasodilation. In this study, we investigated whether a 15-PGDH inhibitor can act as a candidate for blocking these two major mechanisms of CIAKI. We established a CIAKI mouse model by injecting a 10 gram of iodine per body weight (gI/kg) dose of iodixanol into each mouse tail vein. A 15-PGDH inhibitor (SW033291), PGE1, or PGE2 were administered to compare the renal functional parameters, histologic injury, vasoconstriction, and renal blood flow changes. In addition, human renal proximal tubular epithelial cells were cultured in a CM-treated medium. SW033291, PGE1, or PGE2 were added to compare any changes in cell viability and apoptosis rate. CIAKI mice that received SW033291 had lower serum levels of creatinine, neutrophil gelatinase-associated lipocalin, and kidney injury molecule 1 (p < 0.001); lower histologic injury score and TUNEL positive rates (p < 0.001); and higher medullary arteriolar area (p < 0.05) and renal blood flow (p < 0.001) than CM + vehicle group. In cell culture experiments, Adding SW033291 increased the viability rate (p < 0.05) and decreased the apoptosis rate of the tubular epithelial cells (p < 0.001). This 15-PGDH inhibitor blocks the two primary mechanisms of CIAKI, intrarenal vasoconstriction and tubular cell toxicity, and thus has the potential to be a novel prophylaxis for CIAKI. Abbreviations: 15-PGDH: 15-hydroxyprostaglandin dehydrogenase; AMP: adenosine monophosphate; CIAKI: contrast-induced acute kidney injury; CM: contrast media; EP: prostaglandin E2 receptor; hRPTECs: human-derived renal proximal tubule epithelial cells; KIM-1: kidney injury molecule-1; MTT: 3-(4,5-Dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide; NGAL: neutrophil gelatinase-associated lipocalin; PBS: phosphate-buffered saline; PGE1: prostaglandin E1; PGE2: prostaglandin E2; RBF: renal blood flow; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling; α-SMA: α-Smooth muscle actin.

Association between epidermal growth factor (EGF) and EGF receptor gene polymorphisms and end-stage renal disease and acute renal allograft rejection in a Korean population.

Purpose: Epidermal growth factor (EGF) has been found to be associated with the development and repair mechanisms of several renal diseases. In this study, we hypothesized that single nucleotide polymorphisms (SNPs) in EGF or its receptor genes might have an association with end-stage renal disease (ESRD) or acute renal allograft rejection (AR) in a Korean population.Methods: Three-hundred and forty seven recipients of the first renal transplants for ESRD, including 63 AR patients along with 289 healthy adults were included in the study. Five EGF gene SNPs (rs11568835, rs11568943, rs2237051, rs11569017, and rs3756261) and four EGFR gene SNPs (rs1140475, rs2293347, rs1050171, and rs6965469) were analyzed. The genotypes of these SNPs were analyzed using the AxiomTM genome-wide human assay. Statistical analysis was performed using SNPStats and Haploview version 4.2 software. Multiple logistic regression models (codominant, dominant, recessive, and Log-additive) were used to estimate the odds ratio (OR), 95% confidence interval (CI), and P value.Results: One SNP (rs11569017) in the EGF gene showed significant association with ESRD but not with AR. Another SNP (rs11568835) in the EGF gene showed significant association with susceptibility to AR but not with ESRD. One SNP (rs1050171) in the EGFR gene showed significant association with susceptibility to AR but not with ESRD.Conclusion: Our findings suggest that SNPs in the EGF and EGFR gene may be associated with the risk of ESRD and AR development in the Korean population.

Genome-wide association study identifies new susceptible loci of IgA nephropathy in Koreans.

BACKGROUND: Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Recent evidence suggests that genetic factors are related to the pathogenesis of IgAN. We conducted a genome-wide association study (GWAS) to identify novel genetic susceptibility loci for IgAN in a Korean population. METHODS: We enrolled 188 biopsy-confirmed IgAN cases and 455 healthy controls for the discovery stage and explored associations between IgAN and single nucleotide polymorphisms (SNPs) using a customized DNA chip. The significant SNPs from the discovery samples were then selected for replication in an independent cohort with 310 biopsy-confirmed IgAN cases and 438 healthy controls. RESULTS: In the first stage, two SNPs (rs10172700 in LOC105373592 and rs2296136 in ANKRD16) were selected for further association analysis in the next stage. In the replication cohort, rs2296136 in ANKRD16 was significantly associated with IgAN (odds ratio [OR] = 1.40, 95% confidence interval [CI] 0.99-1.98, p = 0.05 in log-additive model, OR = 1.55, 95% CI = 1.06--2.27, p = 0.02 in dominant model, and OR = 0.70, 95% CI = 0.17--2.84, p = 0.62 in recessive model). rs2296136 in ANKRD16 also showed a significant association with IgAN in the entire study population combining GWAS and replication study (p = 0.0045 in log-additive model, p = 0.0027 in dominant model, and p = 0.76 in recessive model). CONCLUSIONS: The SNPs identified in the present study could be good candidate markers for predicting IgAN in Koreans, although further experimental validation is needed.

Hallmarks of Aging in the Liver.

While the liver demonstrates remarkable resilience during aging, there is growing evidence that it undergoes all the cellular hallmarks of aging, which increases the risk of liver and systemic disease. The aging process in the liver is driven by alterations of the genome and epigenome that contribute to dysregulation of mitochondrial function and nutrient sensing pathways, leading to cellular senescence and low-grade inflammation. These changes promote multiple phenotypic changes in all liver cells (hepatocytes, liver sinusoidal endothelial, hepatic stellate and Küpffer cells) and impairment of hepatic function. In particular, age-related changes in the liver sinusoidal endothelial cells are a significant but under-recognized risk factor for the development of age-related cardiometabolic disease.

Effect of Converting From Calcineurin Inhibitor- to Sirolimus-Based Immunosuppressant Regimen on Breast Fibroadenoma Among Kidney Transplant Patients.

The incidence rate of breast fibroadenomas is higher among female kidney transplant (KT) patients treated using cyclosporine (CsA) for immunosuppression than in the general population. As such, there is an effort to convert immunosuppression from CsA or tacrolimus to sirolimus. Our aim was to assess the reversibility of a breast fibroadenoma after conversion in a small cohort of female KT recipients. This was an open-label, single-arm study including 128 female KT recipients, with a positive finding of a breast fibroadenoma in 15. Lesions were classified according to the Breast Imaging Reporting and Data System (BIRADS). Among these 15, a total of 7 converted from tacrolimus to sirolimus and 8 converted from CsA. We measured the change in BIRADS category and hormone and cytokine levels from baseline to 12 months after conversion. The primary outcome was progression or reversal of existing fibroadenomas at 12 months after conversion. Secondary outcomes were differences in hormone and cytokine levels. Conversion from CsA or tacrolimus to sirolimus had no significant effect on the BIRADS classification. However, conversion to sirolimus did produce a significant decrease in the level of transforming growth factor ß cytokine, this level being closely associated with fibroadenomas. Conversion from a calcineurin inhibitor to sirolimus can block the progression of fibroadenomas. Further research is needed to confirm our results.

Inhibition of acute lethal pulmonary inflammation by the IDO-AhR pathway.

The lung is a prototypic organ that was evolved to reduce immunopathology during the immune response to potentially hazardous endogenous and exogenous antigens. In this study, we show that donor CD4+ T cells transiently induced expression of indoleamine 2,3-dioxygenase (IDO) in lung parenchyma in an IFN-γ-dependent manner early after allogeneic hematopoietic stem cell transplantation (HSCT). Abrogation of host IDO expression by deletion of the IDO gene or the IFN-γ gene in donor T cells or by FK506 treatment resulted in acute lethal pulmonary inflammation known as idiopathic pneumonia syndrome (IPS). Interestingly, IL-6 strongly induced IDO expression in an IFN-γ-independent manner when deacetylation of STAT3 was inhibited. Accordingly, a histone deacetylase inhibitor (HDACi) could reduce IPS in the state where IFN-γ expression was suppressed by FK506. Finally, l-kynurenine produced by lung epithelial cells and alveolar macrophages during IPS progression suppresses the inflammatory activities of lung epithelial cells and CD4+ T cells through the aryl hydrocarbon receptor pathway. Taken together, our results reveal that IDO is a critical regulator of acute pulmonary inflammation and that regulation of IDO expression by HDACi may be a therapeutic approach for IPS after HSCT.

Effect of upregulated TLR2 expression from G-CSF-mobilized donor grafts on acute graft-versus-host disease.

Our previous study demonstrated that G-CSF treatment increased the expression of TLR2 in donor grafts; this contributed to rapid engraftment after allogeneic hematopoietic stem cell transplantation (HSCT) in mice. In the current study, we investigated the effects of upregulated TLR2 expression in G-CSF-mobilized donor grafts on acute graft-versus-host disease (GVHD). We found that TLR2 was highly expressed on myeloid cell populations but not T and B cells from the spleens of G-CSF-treated donor mice. After transplantation, the mortality and disease severity in recipients were not significantly different between G-CSF-treated TLR2-/- and wt donor grafts. Although endogenous TLR2 ligand was detected in the serum of both recipients, T cells from TLR2-/- and wt donors have the same ability regarding alloreactivity. Moreover, the blockade of TLR2 signaling in recipients by administering anti-TLR2 blocking antibody after BMT did not lead to a significant difference in acute GVHD compared with control IgG treatment. However, the hematopoietic ability of G-CSF-mobilized lin−c-kit+ HSCs from TLR2-/- donor grafts was lower than that from wt donor grafts. Our results demonstrate that upregulated TLR2 expression in G-CSF-mobilized donor grafts has no effect on acute GVHD, suggesting that TLR2 is a valuable target for increasing HSCT efficiency in order to enhance engraftment without exacerbating acute GVHD.

Transforming growth factor-ß receptor 2 gene polymorphisms are associated with end-stage renal disease.

BACKGROUND: Transforming growth factor-beta (TGF-ß) is a multifunctional cytokine involved in immune disorders, cancer, asthma, lung fibrosis, and chronic kidney disease, and its signal pathways are considered crucial mediators of a variety of cellular processes. In addition, several recent studies have reported that TGF-ß receptor (TGF-ßR) gene polymorphism is associated with chronic kidney disease. However, the association between end-stage renal disease (ESRD) and the TGF-ß gene polymorphism has not been sufficiently investigated. In this study, we hypothesized that polymorphisms of the TGF-ß ligands or their receptors may be related to ESRD. METHODS: We assessed the relationship between four single-nucleotide polymorphisms (SNPs) in the TGF-ßR2 and TGF-ß2 genes and ESRD, in 312 patients with ESRD and 258 controls. RESULTS: Compared with the control participants, the frequencies of the TGF-ßR2 (rs764522(⁎)C) and TGF-ßR2 (rs3087465(⁎)G) alleles were significantly higher in the patients with ESRD. Genotyping analysis demonstrated that two SNPs in TGF-ßR2 of the four SNPs included in the study were significantly associated with ESRD in the codominant 1 [rs764522, odds ratio (OR)=1.65; rs3087465, OR=1.63], dominant (rs764522, OR=1.63; rs3087465, OR=1.57), and log-additive (rs764522, OR=1.54; rs3087465, OR=1.39) models after adjusting for age and sex. CONCLUSION: We suggest that TGF-ßR2 polymorphisms (rs764522 and rs3087465) increase the risk of development of ESRD.

Association studies of cytochrome P450, family 2, subfamily E, polypeptide 1 (CYP2E1) gene polymorphisms with acute rejection in kidney transplantation recipients.

Recent studies have shown that single-nucleotide polymorphisms (SNPs) are associated with allograft rejection in kidney transplantation recipients. We evaluated the possible association between SNPs of the cytochrome P450, family 2, subfamily E, polypeptide 1 (CYP2E1) gene, and acute rejection (AR) among renal transplant patients in a Korean population. We conducted a case-control association study in 63 AR and 284 non-AR kidney transplant recipients. The SNPs of CYP2E1 were genotyped by direct sequencing. Recipient sex (p = 0.023) and the use of tacrolimus (p = 0.017) were significantly different between the two groups. The use of mycophenolate mofetil (MMF) and antibody induction therapy was significantly lower in the AR group. Multiple logistic regression models (codominant, dominant, recessive, and log-additive models) adjusted by sex and type of immunosuppressive regimens were applied to determine the odds ratios (ORs), 95% confidence intervals (CIs), and p-values. The rs2515641 of CYP2E1 showed significant differences between the AR patient group and non-AR group (p = 0.003, OR = 2.55, 95% CI = 1.37-4.75 in the codominant 1 model; p = 0.002, OR = 2.61, 95% CI = 1.43-4.77 in the dominant model; p = 0.0035, OR = 2.13, 95% CI = 1.29-3.50 in the log-additive model). The allele of the rs2515641 SNP also showed a significant association (p = 0.004, OR = 1.99, 95% CI = 1.24-3.21). This study suggests that the CYP2E1 polymorphism may be related to the development of AR in Korean kidney transplantation recipients.

The tryptophan metabolite 3-hydroxyanthranilic acid suppresses T cell responses by inhibiting dendritic cell activation.

The generation of tryptophan (Trp) metabolites by indoleamine 2,3-dioxygenase (IDO) is an effective mechanism for T cell suppression. However, the effect of Trp metabolites on dendritic cells (DCs) remains unclear. Here, we investigated whether the tryptophan metabolite 3-hydroxyanthranilic acid (3-HAA) directly inhibits DC activation and is responsible for T cell suppression. We found that 3-HAA treatment significantly reduced IL-12, IL-6, and TNF-α production in bone marrow-derived DCs (BMDCs) stimulated with LPS. Maturation markers CD40, CD80, CD86, and I-A were also significantly reduced. Moreover, treatment with 3-HAA decreased the ability of DCs to stimulate T cell activation and differentiation in vitro and in vivo. Finally, we observed that phospho-JNK and phospho-38 levels were reduced in 3-HAA-treated DC2.4 cells and BMDCs. These results suggest that the tryptophan metabolite 3-HAA suppresses T cell responses by inhibiting DC activation.

Association between a TGFBR2 gene polymorphism (rs2228048, Asn389Asn) and acute rejection in Korean kidney transplantation recipients.

Transforming growth factor-ß (TGF-ß) signaling transduction initiates TGF-ß activation, resulting in activation of TGF-ß receptor II (TGFBR2). Any quantitative and qualitative changes in TGFBR2 are expected to affect the TGF-ß signaling pathway, which occupies a central position with respect to the regulation of cell growth, differentiation, apoptosis, immune reaction, angiogenesis and extracellular matrix formation. Recent studies have shown that TGF-ß1 gene polymorphisms may confer susceptibility to early acute and chronic allograft rejection in kidney transplantation recipients. In this study, we assessed whether polymorphisms of the TGFBR2 gene were associated with susceptibility to kidney transplantation rejection. A total of 347 renal allograft recipients transplanted at three centers in Korea were analyzed. Three SNPs (rs764522, rs3087465, rs2228048) of the TGFBR2 gene were genotyped from genomic DNA with direct sequencing. Multiple logistic regression models (codominant, dominant, recessive, and log-additive) were performed to evaluate odds ratios (ORs), 95% confidence intervals (CIs), and p-values. A total of 63 patients (18%) developed acute rejection (AR). There were no significant differences in age, sex, number of HLA mismatches, cause of renal failure, or immunosuppressant regimen between the AR and non-AR group. The synonymous SNP rs2228048 was significantly associated with AR (p = 0.020 in recessive model, and p = 0.036 in log-additive model. The allele frequencies of rs2228048 were different between the AR and non-AR group (p = 0.026). These results suggest that the synonymous TGFBR2 gene SNP rs2228048 may be associated with the development of AR in Korean kidney transplantation recipients. Authors Yeong-Hoon Kim and Tae Hee Kim contributed equally to this work and are considered co-first authors.

Fibrillary glomerulonephritis associated with Behçet's syndrome.

Fibrillary glomerulonephritis (FGN) is a rare cause of progressive renal dysfunction resulting in fibrillary deposits in the mesangium and/or glomerular basement membrane (GBM). Some case reports have shown FGN in patients with rheumatoid arthritis and other autoimmune diseases. This is the first case report of FGN in a patient with Behçet's syndrome. The most common renal histological finding in Behçet's syndrome is secondary amyloidosis. A 46-year-old woman with a 4-year history of Behçet's syndrome was referred to the nephrology clinic with foamy urine with non-selective proteinuria (urine protein-to-creatinine ratio was 1400 mg protein/g creatinine) and microscopic hematuria. Serum and urine protein electrophoresis showed no evidence of monoclonal gammopathy. A renal biopsy was performed. Light microscopy showed mesangial widening and nodular expansion with hyaline deposits. Immunofluorescence microscopy revealed immunoglobulin M deposits in the mesangium. Congo red staining was negative. Electron microscopy showed fibrillary deposits on the GBM. Pathological findings were consistent with FGN. She had been taking 50 mg azathioprine and 3000 mg mesalazine per day for 4 years due to Behçet's syndrome, so we did not add any other immunosuppressive agents or corticosteroids. Treatment of this glomerulopathy is not promising. It has been noted that none of the various approaches, including corticosteroid, plasmapheresis, and cytotoxic therapy, improves prognosis.

Conserved regulatory motifs at phenylethanolamine N-methyltransferase (PNMT) are disrupted by common functional genetic variation: an integrated computational/experimental approach.

The adrenomedullary hormone epinephrine transduces environmental stressors into cardiovascular events (tachycardia and hypertension). Although the epinephrine biosynthetic enzyme PNMT genetic locus displays both linkage and association to such traits, genetic variation underlying these quantitative phenotypes is not established. Using an integrated suite of computational and experimental approaches, we elucidate a functional mechanism for common (minor allele frequencies > 30%) genetic variants at PNMT. Transcription factor binding motif prediction on mammalian PNMT promoter alignments identified two variant regulatory motifs, SP1 and EGR1, disrupted by G-367A (rs3764351), and SOX17 motif created by G-161A (rs876493). Electrophoretic mobility shifts of approximately 30-bp oligonucleotides containing ancestral versus variant alleles validated the computational hypothesis. Queried against chromaffin cell nuclear protein extracts, only the G-367 and -161A alleles shifted. Specific antibodies applied in electrophoretic gel shift experiments confirmed binding of SP1 and EGR1 to G-367 and SOX17 to -161A. The in vitro allele-specific binding was verified in cella through promoter reporter assays: lower activity for -367A haplotypes cotransfected by SP1 (p = 0.002) and EGR1 (p = 0.034); and enhanced inhibition of -161A haplotypes (p = 0.0003) cotransfected with SP1 + SOX17. Finally, we probed cis/trans regulation with endogenous factors by chromatin immunoprecipitation using SP1/EGR1/SOX17 antibodies. We describe the systematic application of complementary computational and experimental techniques to detect and document functional genetic variation in a trait-associated regulatory region. The results provide insight into cis and trans transcriptional mechanisms whereby common variation at PNMT can give rise to quantitative changes in human physiological and disease traits. Thus, PNMT variants in cis may interact with nuclear factors in trans to govern adrenergic activity.