Genomic analyses of germline and somatic variation in high-grade serous ovarian cancer.

BACKGROUND: High-grade serous ovarian cancers (HGSCs) display a high degree of complex genetic alterations. In this study, we identified germline and somatic genetic alterations in HGSC and their association with relapse-free and overall survival. Using a targeted capture of 557 genes involved in DNA damage response and PI3K/AKT/mTOR pathways, we conducted next-generation sequencing of DNA from matched blood and tumor tissue from 71 HGSC participants. In addition, we performed the OncoScan assay on tumor DNA from 61 participants to examine somatic copy number alterations (SCNA). RESULTS: Approximately one-third of tumors had loss-of-function (LOF) germline (18/71, 25.4%) or somatic (7/71, 9.9%) variants in the DNA homologous recombination repair pathway genes BRCA1, BRCA2, CHEK2, MRE11A, BLM, and PALB2. LOF germline variants also were identified in other Fanconi anemia genes and in MAPK and PI3K/AKT/mTOR pathway genes. Most tumors harbored somatic TP53 variants (65/71, 91.5%). Using the OncoScan assay on tumor DNA from 61 participants, we identified focal homozygous deletions in BRCA1, BRCA2, MAP2K4, PTEN, RB1, SLX4, STK11, CREBBP, and NF1. In total, 38% (27/71) of HGSC patients harbored pathogenic variants in DNA homologous recombination repair genes. For patients with multiple tissues from the primary debulking or from multiple surgeries, the somatic mutations were maintained with few newly acquired point mutations suggesting that tumor evolution was not through somatic mutations. There was a significant association of LOF variants in homologous recombination repair pathway genes and high-amplitude somatic copy number alterations. Using GISTIC analysis, we identified NOTCH3, ZNF536, and PIK3R2 in these regions that were significantly associated with an increase in cancer recurrence and a reduction in overall survival. CONCLUSIONS: From 71 patients with HGCS, we performed targeted germline and tumor sequencing and provided a comprehensive analysis of these 557 genes. We identified germline and somatic genetic alterations including somatic copy number alterations and analyzed their associations with relapse-free and overall survival. This single-site long-term follow-up study provides additional information on genetic alterations related to occurrence and outcome of HGSC. Our findings suggest that targeted treatments based on both variant and SCNA profile potentially could improve relapse-free and overall survival.

Genomic Analyses of Germline and Somatic Variation in High-Grade Serous Ovarian Cancer.

Background High-grade serous ovarian cancers (HGSCs) display a high degree of complex genetic alterations. In this study, we identified germline and somatic genetic alterations in HGSC and their association with relapse-free and overall survival. Using a targeted capture of 577 genes involved in DNA damage response and PI3K/AKT/mTOR pathways, we conducted next-generation sequencing of DNA from matched blood and tumor tissue from 71 HGSC participants. In addition, we performed the OncoScan assay on tumor DNA from 61 participants to examine somatic copy number alterations. Results Approximately one-third of tumors had loss-of-function germline (18/71, 25.4%) or somatic (7/71, 9.9%) variants in the DNA homologous recombination repair pathway genes BRCA1, BRCA2, CHEK2, MRE11A, BLM , and PALB2 . Loss-of-function germline variants also were identified in other Fanconi anemia genes and in MAPK and PI3K/AKT/mTOR pathway genes. Most tumors harbored somatic TP53 variants (65/71, 91.5%). Using the OncoScan assay on tumor DNA from 61 participants, we identified focal homozygous deletions in BRCA1, BRCA2, MAP2K4, PTEN, RB1, SLX4, STK11, CREBBP , and NF1 . In total, 38% (27/71) of HGSC patients harbored pathogenic variants in DNA homologous recombination repair genes. For patients with multiple tissues from the primary debulking or from multiple surgeries, the somatic mutations were maintained with few newly acquired point mutations suggesting that tumor evolution was not through somatic mutations. There was a significant association of loss-of-function variants in homologous recombination repair pathway genes and high-amplitude somatic copy number alterations. Using GISTIC analysis, we identified NOTCH3, ZNF536 , and PIK3R2 in these regions that were significantly associated with an increase in cancer recurrence and a reduction in overall survival. Conclusions From 71 patients with HGCS, we performed targeted germline and tumor sequencing and provided a comprehensive analysis of these 577 genes. We identified germline and somatic genetic alterations including somatic copy number alterations and analyzed their associations with relapse-free and overall survival. This single-site long-term follow-up study provides additional information on genetic alterations related to occurrence and outcome of HGSC. Our findings suggest that targeted treatments based on both variant and SCNA profile potentially could improve relapse-free and overall survival.

Multivisceral resection of locally advanced colorectal cancer in an African referral centre.

BACKGROUND: Colorectal cancer (CRC) is common and often presents with advanced disease in Africa. Multivisceral resection (MVR) improves survival in locally advanced (T4b) CRC. The aim was to describe the management and outcomes of patients with clinical T4b CRC without metastatic disease who underwent MVR. METHODS: A retrospective review of patients with T4 CRC who underwent MVR between January 2008 and December 2013. RESULTS: Four hundred and ninety-four patients were included. Of the 158 with suspected T4 cancer, 44 had MVR, of which one was excluded due to metastases. The mean age was 64 years. The male to female ratio was 1:1. The most commonly resected extra-colorectal structure was the abdominal wall (21%). The median survival was 68 months (SD 13.9). The 5-year disease free (DFS) and overall survival (OS) were 46% and 55%, respectively. Survival of patients with colon and rectum cancer was similar. Intraoperative tumour spillage, vascular/perineural invasion, and anastomotic leakage were independent predictors of survival. CONCLUSION: Multivisceral resection of locally advanced (T4b) CRC is feasible in the African context. Complete resection improves survival and should be the goal.

Bilateral versus unilateral botulinum toxin injections for chronic anal fissure: a randomised trial.

BACKGROUND: Botulinum toxin injected into the internal anal sphincter is used in the treatment of chronic anal fissure but there is no standardised technique for its administration. This randomised single centre trial compares bilateral (either side of fissure) to unilateral injection. METHODS: Participants were randomised to receive bilateral (50 + 50 units) or unilateral (100 units) Dysport® injections into the internal anal sphincter in an outpatient setting. Injection-related pain assessed by visual analogue scale was the primary outcome measure. Secondary outcomes were healing rate, fissure pain, incontinence, and global health scores. RESULTS: Between October 2008 and April 2012, 100 patients with chronic anal fissure were randomised to receive bilateral or unilateral injections. Injection-related pain was comparable in both groups. There was no difference in healing rate. Initially, there was greater improvement in fissure pain in the bilateral group but at 1 year the unilateral group showed greater improvement. Cleveland Clinic Incontinence score was lower in the unilateral group in the early post-treatment period and global health assessment (EuroQol EQ-VAS) was higher in the unilateral group at 1 year. CONCLUSIONS: Injection-related pain was similar in bilateral and unilateral injection groups. Unilateral injection was as effective as bilateral injections in healing and improving fissure pain without any deterioration in continence.

Stenting as first-line management for all patients with nonperforating left-sided obstructing colorectal cancer.

AIM: Since 2005, we have used self-expanding metal stents (SEMS) as primary treatment for all patients with left-sided obstructing colorectal cancer without evidence of perforation. The purpose of this study was to assess the safety and efficacy of this treatment. METHOD: This was a prospective study of consecutive patients with left-sided obstructing colorectal cancer without perforation or peritonitis treated between January 2005 and June 2009. SEMS placement was attempted in all cases. Emergency surgery was reserved for patients in whom a stent placement failed. After successful decompression, surgery was offered to patients with potentially curable disease. RESULTS: Seventy-seven patients were included, with successful SEMS placement in 60/77 (78%) patients, 25 as a bridge to surgery and 35 for palliation. Immediate complications occurred in two (3%) cases. There was no mortality. Of 35 patients in whom SEMS was for palliation, 32 (91%) avoided surgery altogether. A stoma was fashioned in 5 (8.3%) of the 60 patients who were successfully stented, and in 12 (71%) of the 17 patients in whom stenting failed (P = 0.0001). CONCLUSION: A SEMS-based management protocol for patients with large bowel obstruction due to colorectal cancer is safe and effective.

Maternal influence of prolyl endopeptidase on fat mass of adult progeny.

BACKGROUND: Maternal genotype has lifetime effects on progeny, but few specific genes, and no proteases, are known to underlie maternal effects. Prolyl endopeptidase (PREP) is a serine protease with putative substrates that regulate appetite or milk production. OBJECTIVE: To test effects of PREP on obesity phenotypes in mice. DESIGN: Mice with a gene trap (GT) of PREP (PREP(gt/gt)) on the C57BL/6J (B6) background were generated. Minimal PREP protein was detected by western blot. In Experiment 1, direct effects of PREP were measured in littermate mice derived from intercrosses of heterozygotes (PREP(WT/gt)). In Experiment 2, maternal effects of PREP were measured in reciprocal crosses of heterozygous (PREP(WT/gt)) and wild-type (WT) (PREP(WT/WT)) males and females. DIETS: Mice were fed either low-fat (LF, Experiments 1 and 2) or high-fat (HF, Experiment 1) defined diets. MEASUREMENTS: Adiposity index (AI) was calculated from body weight (BW) and weights of four fat depots measured in 120-day-old mice. Fasting plasma glucose, insulin and leptin were measured. In vivo plasma alpha-MSH levels were measured by targeted quantitative peptidomics. RESULTS: Experiment 1-In intercross mice, there were significant diet effects, but few genotype effects. There were no genotype effects on BW or AI in males or females on either diet. Experiment 2-In contrast, reciprocal crosses of heterozygous males or females with WT B6 revealed highly significant parent of origin effects on all traits except body length. Progeny (WT and heterozygous genotypes and both sexes) born to female PREP(WT/gt) heterozygotes had fat pads that weighed as much as -twofold more at 120 days old than progeny born to male heterozygotes. CONCLUSION: Heterozygosity for PREP GT results in highly significant maternal effects, whereas homozygosity for the PREP(gt/gt) mutation has a much more limited direct effect.

Genes and networks expressed in perioperative omental adipose tissue are correlated with weight loss from Roux-en-Y gastric bypass.

CONTEXT: Gastric bypass surgery is the most commonly performed bariatric surgical procedure in the United States. Variable weight loss following this relatively standardized intervention has been reported. To date, a method for reliable profiling of patients who will successfully sustain weight loss for the long term has not been established. In addition, the mechanisms of action in accomplishing major weight loss as well as the explanation for the variable weight loss have not been established. OBJECTIVE: To examine whether gene expression in perioperative omental adipose is associated with gastric bypass-induced weight loss. DESIGN: Cross-sectional study of gene expression in perisurgical omental adipose tissues taken/available at the time of operation and total excess weight loss (EWL). SUBJECTS: Fifteen overweight individuals who underwent Roux-en-Y gastric bypass (RYGB) surgery at the University of California Davis Medical Center (BMI: 40.6-72.8 kg/m(2)). MEASUREMENTS: Body weight before and following weight stabilization 18-42 months after surgery. Perioperative omental adipose RNA isolated from 15 subjects was hybridized to Affymetrix HG-U133A chips for 22,283 transcript expression measurements. RESULTS: Downstream analysis identified a set of genes whose expression was significantly correlated with RYGB-induced weight loss. The significant individual genes include acyl-coenzyme A oxidase 1 (ACOX1), phosphodiesterase 3A cGMP-inhibited (PDE3A) and protein kinase, AMP-activated, beta 1 non-catalytic subunit (PRKAB1). Specifically, ACOX1 plays a role in fatty acid metabolism. PDE3A is involved in purine metabolism and hormone-stimulated lipolysis. PRKAB1 is involved in adipocytokine signaling pathway. Gene network analysis revealed that pathways for glycerolipid metabolism, breast cancer and apoptosis were significantly correlated with long-term weight loss. CONCLUSION: This study demonstrates that RNA expression profiles from perioperative adipose tissue are associated with weight loss outcome following RYGB surgery. Our data suggest that EWL could be predicted from preoperative samples, which would allow for informed decisions about whether or not to proceed to surgery.

Seguridad farmacológica y ambiental: disrupción endocrina / Drug and environmental safety: hyroid endocrine disruption

La exposición humana a compuestos químicos que interfieren con la homeostasis hormonal es bien conocida, a pesar de que la evidencia sea muy desigual para los distintos sistemas hormonales. Mientras que la disrupción endocrina de los esteroides (estrógenos y andrógenos) ha merecido gran atención, la de la homeostasis de las hormonas tiroideas está mal entendida, si se exceptúa lo que se refiere a la captación de yodo. La lista de disruptores endocrinos que interfieren con la síntesis, la circulación, la unión a receptores específicos, el metabolismo y la degradación de las hormonas tiroideas crece día a día. A los bifenilospoliclorados (PCB), las dioxinas y los furanos, se unen ahora los compuestos bromados retardadores de la llama, los bisfenoles y losftalatos. Cambios sutiles en las concentraciones de las hormonas tiroideas pueden ocasionar efectos adversos en períodos esenciales del desarrollo, de tal manera que se empieza a ver los efectos de tal exposición ahora, una vez que los mecanismos que ligan hormonastiroideas y neurodesarrollo son cada vez más evidentes ( AU)

Human exposure to environmental chemicals that disrupt endocrine homeostasis has been related to several hormone systems. Sex hormones (estrogen sand androgens) have received special attention, but thyroid hormone disruption is not so well known except in the special case of iodine intake deficiency. The list of chemicals that alter synthesis, circulation, binding to specific receptors, metabolism and degradation of thyroid hormones increases daily. Brominated flameretardants, bisphenols and phthalates are now included alongside polychlorinated biphenyls (PCBs), dioxins and furans. Subtle changes in circulating thyroid hormones may have undesirable effects during development. As our understanding of the role of thyroid hormones in neurodevelopment improves, exposure to environmental thyroid disruptors becomes a matter of increasing concern (AU)

Multiple linked mouse chromosome 7 loci influence body fat mass.

BACKGROUND: Congenic mouse strains contain donor mouse strain DNA in genomes otherwise identical to a background strain. They can be used to identify defined chromosomal regions containing obesity genes with small effects. OBJECTIVE: : The objective of this study was to discover congenic strains containing genes that influence body fat in mice and to examine interactions between these genes. DESIGN: A survey of congenic strains showed that the B6.C-Tyr(c) H1(b) Hbb(d)/By (B6.C-H1) congenic strain, with a 24 centiMorgan (cM) donor region from strain BALB/cBy on chromosome 7, had 50% less fat than background C57BL/6By (B6By) mice. The congenic donor region was then divided into 11 smaller overlapping subcongenic regions. Genotype effects on obesity traits in the subcongenics were determined by breeding heterozygotes for each line and comparing phenotypes of littermates with different donor genotypes. RESULTS: At least three subcongenic strains, two with overlapping donor regions and one with a nonoverlapping donor strain region, were found to exhibit significant influences of donor region genotype on obesity. A cross of the two overlapping subcongenics demonstrated that a single gene in the overlap region could not account for the observed obesity effects. We also observed significant obesity differences between genetically identical progeny that were contingent on the genotype of their subcongenic mothers. CONCLUSIONS: These results demonstrate the existence of at least three genes influencing obesity in three subcongenic strains with donor strain chromosomal regions whose size ranges from 0.5 to 5 cM. A maternal effect gene influencing obesity may be present in some subcongenic strains.

Studies of natural allele effects in mice can be used to identify genes causing common human obesity.

Although genes causing rare Mendelian forms of human obesity have provided much useful information about underlying causes of obesity, these genes do not explain significant proportions of common obesity. This review presents evidence that animal models can be used to uncover subtle genetic effects on obesity and can provide a powerful rigorous compliment to human association studies. We discuss the advantages of animal models of obesity, various approaches to discovering obesity genes, and the future of mapping and isolating naturally occurring alleles of obesity genes. We review evidence that it is important to map naturally occurring obesity genes using quantitative trait locus (QTL) mapping, instead of mutagenesis and knockout models because the latter do not allow study of interactions and because naturally occurring obesity alleles can interfere with cloning from mutagenesis projects. Because a substantial percentage of human obesity results from complex interactions, the underlying genes can only be identified by direct studies in humans, which are still very difficult, or by studies in mice that begin with QTL mapping. Finally, we emphasize that animal model studies can be used to prove that a specific gene, only associated with obesity in humans, can indeed be the underlying cause of obesity in mammals.

Uncoupling proteins-2 and 3 influence obesity and inflammation in transgenic mice.

OBJECTIVE: To test the hypothesis that either uncoupling protein-2 UCP2 or UCP3 or both together influence obesity and inflammation in transgenic mice. DESIGN: We generated 12 lines of transgenic mice for both human UCP2 and 3 using native promoters from a human bacterial artificial chromosome (BAC) clone. The BAC expresses no genes other than UCP2 and 3. Mice used for experiments are N4 or higher of backcross to C57BL/6J (B6). Each experiment used transgenic mice and their nontransgenic littermates. RESULTS: Northern blots confirmed expression on human UCP2 in adipose and spleen, while human UCP3 expression was detectable in gastrocnemius muscle. Western blots demonstrated a four-fold increase of UCP2 protein in spleens of Line 32 transgenic animals. Heterozygous mice of four lines showing expression of human UCP2 in spleen were examined for obesity phenotypes. There were no significant differences between Lines 1 and 32, but female transgenics of both lines had significantly smaller femoral fat depots than the control (littermate) mice (P=0.015 and 0.005, respectively). In addition, total fat of transgenic females was significantly less in Line 1 (P=0.05) and almost significantly different in Line 32 (P=0.06). Male Line 1 mice were leaner (P=0.04) while male Line 32 mice were almost significantly leaner (P=0.06). Heterozygous mice of Lines 35 and 44 showed no significant differences from the nontransgenic littermate controls. Effects of the UCP2/UCP3 transgene on obesity in Line 32 mice were confirmed by crossing transgenic mice with the B6.Cg-Ay agouti obese mice. B6.Cg-Ay carrying the UCP2/UCP3 transgene from Line 32 were significantly leaner than nontransgenic B6.Cg-Ay mice. Line 32 UCP2/UCP3 transgenics showed increased hypothalamic Neuropeptide (NPY) levels and food intake, with reduced spontaneous physical activity. Transgenic baseline interleukin4 (IL-4) and interleukin6 (IL-6) levels were low with lower or later increases after endotoxin injection compared to wild-type littermates. Endotoxin-induced fever was also diminished in transgenic male animals. Low-density lipoprotein (LDL) cholesterol levels were significantly higher in both Line 1 and 32 transgenics (P=0.05 and 0.001, respectively) after they had been placed on a moderate fat-defined diet containing 32% of calories from fat for 5 weeks. CONCLUSION: Moderate overexpression of UCP2 and 3 reduced fat mass and increased LDL cholesterol in two independent lines of transgenic mice. Thus, the reduced fat mass cannot be due to insertional mutagenesis since virtually identical fat pad weights and masses were observed with the two independent lines. Line 32 mice also have altered inflammation and mitochondrial function. We conclude that UCP2 and/or 3 have small but significant effects on obesity in mice, and that their mechanism of action may include alterations of metabolic rate.

Physiological effects of variants in human uncoupling proteins: UCP2 influences body-mass index.

The purpose of this review is to summarize the evidence from more than 40 studies that naturally occurring variants of uncoupling proteins 1-3 (UCP1-3) have detectable physiological effects in humans. Although UCP1 is known to influence mitochondrial proton leak in vitro and core body temperature in mice, genetic studies in humans have produced only weak evidence for association of naturally occurring variants with body-mass index (BMI); the best-reported P value is 0.01. In contrast, current evidence is consistent with the hypothesis that UCP2 and 3 influence BMI, since the best reported P values are better: four studies report associations of 0.001 (2 studies) to 0.002 (1 study) and 0.005 (1 study) for a UCP2 insertion/deletion variant, while the best P values for association of UCP3 with BMI are 0.003 (1 study) and 0.0037 (1 study). UCP2 and 3 are adjacent to each other on chromosome 11 and variants in each are in linkage disequilibrium. Thus, variants in UCP2 or 3 may influence results from association studies of variants in the other. Since UCP2 has a greater influence on BMI in humans than UCP3, then the two most likely hypotheses are that only UCP2 affects BMI, and positive results for UCP3 result from linkage disequilibrium to UCP2, or both UCP2 and 3 affect BMI. It is unlikely that only UCP3 influences BMI. UCP2 associations have been observed in a variety of ethnic groups, including Caucasians, African Americans, South Indians and Chinese. Consistent results from diverse ethnic groups are concordant with the hypothesis that the UCP2 insertion/deletion variant itself underlies the association with BMI.

Injury prevention and control in children.

Injury is the number one cause of death and life-years lost for children. In children, injury mortality is greater than childhood mortality from all other causes combined. Modern injury prevention and control seeks to prevent and limit or control injuries through the 4 Es of injury prevention: engineering, enforcement, education, and economics. Emergency physicians are often placed in a critical role in the lives of individuals, are respected authorities on the health and safety of children and adults, and have daily exposure to high-risk populations. This gives emergency physicians a unique perspective and an opportunity to take an active role in injury control and prevention. Specific methods or strategies for promulgating injury prevention and control in our emergency medicine practices are suggested, ranging from education (for our patients and health professionals); screening and intervention for domestic violence, child maltreatment, drug-alcohol dependency and abuse; data collection; reporting unsafe products; research; legislation; serving in regulatory and governmental agencies; emergency medical services-community involvement; and violence prevention. Emergency physicians can play a significant role in decreasing pediatric injury and its concomitant morbidity and mortality.

Biological influences on obesity.

Severely obese children are even more likely to have mutations in obesity genes than are severely obese adults. Thus, investigators searching for obesity genes commonly focus on children, with the result that many human obesity genes were first identified in studies of children. Although the development of obesity depends on living in an obesity-promoting environment, it also is influenced strongly by individual genetic composition. Thus, the discovery of new obesity genes provides new opportunities to identify causes of severe obesity. Finally, identification of individual causes of obesity may, in the future, provide for a safe, effective, and individualized treatment recommendation for each obese person.

Interstitial duplication of the short arm of chromosome 1 in a newborn with congenital heart disease and multiple malformations.

Interstitial duplications of chromosomes 1p are rare, with only 14 cases previously reported in the literature, and those have not revealed a unique syndrome. The phenotypes include multiple congenital abnormalities and both intra- and extra-uterine growth retardation. In general, the patients do poorly and do not survive beyond the age of several months. We report a newborn male with karyotype 46, XY, inv dup(1)(qter--> p34.3::p34.3-->p32.3::34.3-->pter) with multiple congenital abnormalities including congenital heart disease and co-existing portal and pulmonary hypertension. The chromosome 1 origin of the extra material was confirmed with fluorescent in situ hybridization (FISH). Review of the GDB [Human Genome Database, 1990] reveals that the duplicated region includes the locus EDN2 that encodes endothelin-1, a potent vasoconstrictor, making genetic overdosage of this protein a likely etiology of the pulmonary hypertension. The diffuse abnormalities show effects in multiple cell lines and suggest that this region of chromosome 1p could be involved in determining cell migration and/or differentiation during organogenesis.

Structure-function relationships in UCP1, UCP2 and chimeras: EPR analysis and retinoic acid activation of UCP2.

Uncoupling proteins (UCPs) are composed of three repeated domains of approximately 100 amino acids each. We have used chimeras of UCP1 and UCP2, and electron paramagnetic resonance (EPR), to investigate domain specific properties of these UCPs. Questions include: are the effects of nucleotide binding on proton transport solely mediated by amino acids in the third C-terminal domain, and are the amino acids in the first two domains involved in retinoic or fatty acid activation? We first confirmed that our reconstitution system produced UCP1 that exhibited known properties, such as activation by fatty acids and inhibition of proton transport by purine nucleotides. Our results confirm the observations reported for recombinant yeast that retinoic acid, but not fatty acids known to activate UCP1, activates proton transport by UCP2 and that this activation is insensitive to nucleotide inhibition. We constructed chimeras in which the last domains of UCP1 or UCP2 were switched and tested for activation by fatty acids or retinoic acid and inhibition by nucleotides. U1U2 is composed of mUCP1 (amino acids 1-198) and hUCP2 (amino acids 211-309). Fatty acids activated proton transport of U1U2 and GTP mediated inhibition. In the other chimeric construct U2U1, hUCP2 (amino acids 1-210) and mUCP1 (amino acids 199-307), retinoic acid still acted as an activator, but no inhibition was observed with GTP. Using EPR, a method well suited to the analysis of the structure of membrane proteins such as UCPs, we confirmed that UCP2 binds nucleotides. The EPR data show large structural changes in UCP1 and UCP2 on exposure to ATP, implying that a putative nucleotide-binding site is present on UCP2. EPR analysis also demonstrated changes in conformation of UCP1/UCP2 chimeras following exposure to purine nucleotides. These data demonstrate that a nucleotide-binding site is present in the C-terminal domain of UCP2. This domain was able to inhibit proton transport only when fused to the N-terminal part of UCP1 (chimera U1U2). Thus, residues involved in nucleotide inhibition of proton transport are located in the two first carrier motifs of UCP1. While these results are consistent with previously reported effects of the C-terminal domain on nucleotide binding, they also demonstrate that interactions with the N-terminal domains are necessary to inhibit proton transport. Finally, the results suggest that proteins such as UCP2 may transport protons even though they are not responsible for basal or cold-induced thermogenesis.

Mitochondrial uncoupling protein 2 (UCP2) in the nonhuman primate brain and pituitary.

Energy dissipating mechanisms and their regulatory components represent key elements of metabolism and may offer novel targets in the treatment of metabolic disorders, such as obesity and diabetes. Recent studies have shown that a mitochondrial uncoupling protein (UCP2), which uncouples mitochondrial oxidation from phosphorylation, is expressed in the rodent brain by neurons that are known to regulate autonomic, metabolic, and endocrine processes. To help establish the relevance of these rodent data to primate physiology, we now examined UCP2 messenger RNA and peptide expressions in the brain and pituitary gland of nonhuman primates. In situ hybridization histochemistry showed that UCP2 messenger RNA is expressed in the paraventricular, supraoptic, suprachiasmatic, and arcuate nuclei of the primate hypothalamus and also in the anterior lobe of the pituitary gland. Immunocytochemistry revealed abundant UCP2 expression in cell bodies and axonal processes in the aforementioned nuclei as well as in other hypothalamic and brain stem regions and all parts of the pituitary gland. In the hypothalamus, UCP2 was coexpressed with neuropeptide Y, CRH, oxytocin, and vasopressin. In the pituitary, vasopressin and oxytocin-producing axonal processes in the posterior lobe and POMC cells in the intermediate and anterior lobes expressed UCP2. On the other hand, none of the GH-producing cells of the anterior pituitary was found to produce UCP2. The abundance and distribution pattern of UCP2 in the primate brain and pituitary suggest that this protein is evolutionary conserved and may relate to central autonomic, endocrine and metabolic regulation.