ORIGINAL RESEARCH Association of PDE11A global haplotype with major depression and antidepressant drug response Huai-Rong Luo Abstract: Cyclic nucleotide phosphodiesterases (PDEs) hydrolyze the intracellular second Gui-Sheng Wu messengers cAMP and cGMP to their corresponding monophosphates. PDEs play an important Chuanhui Dong role in signal transduction by regulating the intracellular concentration of cyclic nucleotides. Mauricio Arcos-Burgos We have previously shown that the individual haplotype GAACC in the PDE11A gene was Luciana Ribeiro associated with major depressive disorder (MDD) based on block-by-block analysis. There are Julio Licinio two PDE genes, PDE11A and PDE1A, located in chromosome 2q31–q32. In this study, we have further explored whether the whole region 2q31–q32 contribute to MDD or antidepressant Ma-Li Wong response 278 depressed Mexican-American participants and 321 matched healthy controls. Center on Pharmacogenomics, Although there is no signifi cant interaction between the two genes, the remission rate of individual Department of Psychiatry and Behavioral Science, University carrying the combination genotype at rs1880916 (AG/AA) and rs1549870 (GG) is signifi cantly of Miami Miller School of Medicine, increased. We analyzed the global haplotype by examining 16 single-nucleotide polymorphisms Miami, FL, USA (SNPs) in PDE11A and six SNPs in PDE1A. None of the haplotypes consisting of six SNPs in the PDE1A have a signifi cant difference between depressed and control groups. Among haplotypes consisting of 16 SNPs across 440 kb in the PDE11A gene, 18 common haplotypes (with frequency higher than 0.8%) have been found in the studied population. Six haplotypes showed signifi cantly different frequencies between the MDD group and the control group. The phylogenetic network result for the 16 SNPs showed that several historic recombination events have happened in the PDE11A gene. The frequency of one haplotype is signifi cantly lower in the remitter group than in the nonremitter group for the depressed participants treated with either desipramine or fl uoxetine. Thus, our data suggest that the PDE11A global haplotype is associated with both MDD and antidepressant drug response. Keywords: PDE11A, major depression, antidepressant, haplotype, linkage disequilibrium, recombination Introduction The 3', 5'-cyclic nucleotides cAMP and cGMP function as second messengers in a wide variety of signal transduction pathways. 3', 5'-cyclic nucleotide phosphodies- terases (PDEs) catalyze the hydrolysis of cAMP and cGMP to the corresponding 5’-monophosphates and provide a mechanism to downregulate cAMP- and cGMP- signaling. Human PDEs are composed of 21 genes and are categorized into 11 families based on sequence homology, enzymatic properties, and sensitivity to inhibitors.1–3 Correspondence: Ma-Li Wong PDE11A gene is the most recently identifi ed and cloned member of the PDE Professor and Vice-Chair for Translational 4 Research, Director of Center protein superfamily. Four N-terminal transcript variants (PDE11A1, A2, A3, and A4) on Pharmacogenomics, Department encoding different isoforms have been found for this gene.5,6 The PDE11A1, A2, and of Psychiatry and Behavioral Sciences, University of Miami Miller School A3 have a catalytic domain and an N-terminus GAF domain, while the full-length of Medicine, Batchelor Children’s form, PDE11A4, contains two GAF domains and a catalytic domain.4–7 The GAF Research Institute, 1580 NW 10th Avenue, Room 633-A, Miami, domain in PDE11A is homologous to other signaling molecule as found in PDE2, FL 33136, USA PDE5, PDE6, and PDE10.1–3,8 The GAF domain is involved in high affi nity allosteric + Tel 1 305 243 4727 cGMP and other small signaling molecules binding. Because of their unique ligand- Fax +1 305 2439708 Email [email protected] binding topologies, the GAF domains of PDEs are likely to offer good new targets Neuropsychiatric Disease and Treatment 2009:5 163–170 163 © 2009 Luo et al, publisher and licensee Dove Medical Press Ltd. This is an Open Access article which permits unrestricted noncommercial use, provided the original work is properly cited. Luo et al for rational drug design.9 PDE11A exhibits properties of of Ն18 with item number 1 (depressed mood) rated Ն2. dual-substrate PDE and hydrolyzes both cAMP and cGMP Detailed inclusion and exclusion criteria for both control 4–6 12,13,15 into AMP and GMP respectively with similar Km values. and depressed participants were described previously. The Km for cAMP and cGMP were similar for all the four We used diagnostic and ratings instruments that have been PDE11A variants.4–6 fully validated in English and Spanish, and all assessments Haplotypes provide a record of evolution history more were conducted in the participants’ primary language. All accurately than individual single-nucleotide polymorphisms Mexican-American participants aged 21–68 years had at (SNPs), they can also capture linkage disequilibrium (LD) least three grandparents born in Mexico. Written informed and recombination hotspots information of a genomic region consent was obtained from each participant. more completely. Individual haplotype results detected by All patients had an initial comprehensive psychiatric haplotype blocks may vary considerably from different and medical assessment and, if enrolled, had nine weeks of algorithms since the methods for block defi nition are still structured follow up assessments. The study consisted of under devising and no single approach is appropriate for two phases: a 1-week single-blind placebo lead-in phase to all datasets.10 If a recombination hotspot occurs within one minimize the impact of placebo responders followed, if par- gene, using this gene as candidate may not be appropriate. ticipants continue to meet the inclusion criteria after phase 1, An alternative to individual haplotype association study is by random assignment to one of the two treatment groups: to perform multimarker association analysis with multiple fl uoxetine 10–40 mg/day or desipramine 50–200 mg/day, adjacent markers,11 that is global haplotype. In unrelated indi- administered in a double-blind manner for eight weeks, viduals, PHASE program has been widely used to infer the with blind dose escalation based on clinical outcomes. In the most likely haplotype that an individual has inherited.11 Since depressed group, 230 participants received treatment in our we previously demonstrated a signifi cant association between double-blind clinical trial. Of those, 143 patients completed an individual haplotype in the PDE11A gene and major the study, 61 attained remission, defi ned as having a fi nal depressive disorder (MDD),12 and two PDE genes (PDE11A HAM-D21 score of Ͻ8, and the remainder (n = 82) were and PDE1A) are located in chromosome 2q31–q32, we now categorized as nonremitters. evaluate if the whole region 2q31–q32 is associated with MDD by analyzing the gene–gene interaction. Combinations Genotype procedure of the individual haplotypes in multiple loci might determine The Illumina human SNP linkage analysis platform (Illumina, the complexity of an individual’s susceptibility for MDD and San Diego, CA) was used for genotyping.16,17 Briefl y, all outcome of antidepressant treatment. Therefore, we aimed to genomic DNAs were quantitated using PicoGreen and do the haplotype phasing before block partition using PHASE diluted into 100 ng/μl concentration. Then, the DNAs were software by examining 16 SNPs across the PDE11A and six transferred into seven bar-coded plastic 96-well conical SNPs on the PDE1A gene in this study. microtiter plates. Genotyping of 27 SNPs on the PDE1A and PDE11A genes was done at the Wellcome Trust Sanger Materials and methods Institute (Hinxton, UK) using the Golden Gate assay Participants (Illumina) and following the manufacturers’ instruction.16 This study was approved by the IRBs of the University of All genotypes were evaluated using a quantitative quality California Los Angeles and the University of Miami, and it score called GenCall score. A GenCall score ranges from has been registered in ClinicalTrials.gov (NCT00265292). 0 to 1 and refl ects the proximity within a cluster plot of the Genomic DNA samples from 599 Mexican-Americans were intensities of that genotype to the centroid of the nearest used in this study: 278 depressed participants enrolled in a cluster. Poorly performing samples were removed from the pharmacogenetic study of antidepressant treatment response genotyping report fi les, and individual genotypes with Gen- to desipramine or fl uoxetine, and 321 age- and sex-matched Call scores below 0.25 were assigned a nocall. Data quality control participants recruited from the same Mexican-American was assessed by duplicate DNAs (n = 26) across all plates. community in Los Angeles.12,13 Controls were in general Genotypes from nonmatching duplicates were dropped; they good health but were not screened for medical or psychiatric were also dropped if they had one missing data point. Devia- illness. Inclusion criteria included DSM-IV diagnosis of a tion from Hardy–Weinberg equilibrium (HWE) was tested current unipolar major depressive episode, with a 21-item separately for the control and depressed groups by using the Hamilton Depression Rating Scale (HAM-D21) score14 ALLELE procedure in SAS/Genetics 9.1.3 (SAS Institute, 164 Neuropsychiatric Disease and Treatment 2009:5 PDE11A haplotype associated with major depression and drug response Cary, NC). SNPs that were not in HWE in the control group population stratifi cation in our data.18