Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe

Effects of age on molecular pathways regulating bone formation in humans: A key role for notch and Rorβ signaling

Despite extensive studies in mice, there is currently little information on the molecular pathways contributing to age-related bone loss in humans. In part, this stems from the difficulty of obtaining trephine bone biopsies (~5-7 mm diameter) in normal volunteers. Thus, we used the standard clinical approach hematologists employ for bone marrow aspirates and biopsies to obtain needle biopsies (1-2 mm diameter) from the posterior iliac crest in 20 young (30¡5 yr) and 20 old (73¡7 yr)women. We coupled this to customized, in-house QPCR analyses of 288 genes related to bone metabolism, including genes reflecting 17 pre-specified clusters/pathways (e.g.,Wnt targets) and 71 genes linked to SNPs from GWAS studies (Nat Genet 44:491,2012). Genes in pre-specified pathways were analyzed using a cluster analysis (O’Brien Umbrella Test) which tests for concordant changes in multiple genes in the pathway. One of the most highly upregulated pathways in the old women was Notch (P =0.003), which is known to modulate age-related bone loss in mice (Nat Med 14:306,2008). Individual significant (P,0.05) gene changes in this pathway werehes1(1.6x),hey1(1.8x),heyL(1.5x), andJag1(1.2x). In addition, recent studies have identified retinoic acid receptor-related orphan receptorβ (Rorβ) as an important regulator of osteogenesis that is markedly upregulated in bone marrow mesenchymal cells from aged versus young mice (JBMR 27:891, 2012).Rorβ itself (1.6x) as well as multiple Rorβ target genes (P = 0.001 for the pathway) were also upregulated in the biopsies from the old women. Both Notch and Rorβ signaling inhibit runx2 activity, there by potentially blocking osteoblast differentiation. Interestingly, a panel of stem cell markers was significantly upregulated with aging (P = 0.022), including nestin (2.0x),CD146(1.4x), and nanog (1.3x), suggesting that activation of Notch and Rorβ signaling may result in a block in osteoblast differentiation with resultant expansion of the stem cell pool within bone. Of the 71 GWAS genes, 11 were significantly altered with aging, most notablymmp7(4.0x). Other individual gene changes of interest with aging included rankl (1.6x) and fgf23(2.0x).In summary, we describe a novel approach coupling needle biopsies of bone to customized QPCR analyses to study genes/pathways regulating bone metabolism in humans. Our work validates, in humans, several pathways associated with age-related bone loss in mice, including Notch and Rorβ signaling

Estrogen reduces bone sost mRNA and circulating sclerostin levels in postmenopausal women

Studies in postmenopausal women have shown that estrogen (E) reduces circulating sclerostin levels (JBMR 26:27, 2011). However, recent studies in mice(JBMR 28:618, 2013) found no significant effects of ovariectomy on serum sclerostin levels and lack of a relationship between circulating sclerostin and sost mRNA levels in various bones. To resolve this issue in humans, we measured serum sclerostin and bone sost mRNA levels in needle biopsies (1-2 mm diameter) from 20 postmenopausal women (71¡5 yr) treated with transdermal estradiol (0.05mg/d) for 3 weeks and 20untreated control women (73¡7 yr). Serum sclerostin levels were 29% lower (P =0.008) in the E-treated compared to the control women. Concomitantly, bone sost mRNA levels were reduced by 48% (P = 0.03) in the E-treated women. Interestingly ,bone sost mRNA levels were significantly correlated with serum sclerostin levels in the E-treated (r = 0.57, P = 0.008), but not in the control women (r = -0.25, P = 0.280). In addition, mRNA levels of the sclerostin domain-containing protein 1 (sostdc1), a sclerostin-related protein that is another Wnt/BMP inhibitor, were also reduced in the bones of the E-treated compared to the control women (by 54%, P = 0.01).We further extended these studies using customized, in-house QPCR analyses to examine the mRNA expression of genes in other pathways related to bone metabolism, as well as the expression of 71 genes linked to SNPs from GWAS studies (Nat Genet 44:491, 2012). Consistent with studies in mice showing that ovariectomy upregulated components of NFkB signaling, leading to impaired osteoblastic bone formation (Nat Med 15:682, 2009), we found significantly reduced mRNA levels of bothNFkB2andrelB, along with an overall trend (P = 0.028 by cluster analysis) for lower mRNA levels of multiple inflammatory markers in the bone biopsies of the E-treated compared to the control women. Of the 71 GWAS-related genes examined, 14 were modulated in vivo by E treatment. In summary, our studies demonstrate that, in humans, E reduces both bone sost mRNA and circulating sclerostin levels. Further, since bone loss following E deficiency is associated with impaired bone formation relative to bone resorption, our findings point to increases in two key inhibitors of Wnt/BMP signaling, sclerostin andsostdc1, along with increased NFkB signaling, as mediating this relative deficit in bone formation in E-deficient postmenopausal women

Effects of age on bone mRNA levels of sclerostin and other genes relevant to bone metabolism in humans

Although aging is associated with a decline in bone formation in humans, the molecular pathways contributing to this decline remain unclear. Several previous clinical studies have shown that circulating sclerostin levels increase with age, raising the possibility that increased production of sclerostin by osteocytes leads to the age-related impairment in bone formation. Thus, in the present study, we examined circulating sclerostin levels as well as bone mRNA levels of sclerostin using quantitative polymerase chain reaction (QPCR) analyses in needle bone biopsies from young (mean age, 30.0years) versus old (mean age, 72.9years) women. In addition, we analyzed the expression of genes in a number of pathways known to be altered with skeletal aging, based largely on studies in mice. While serum sclerostin levels were 46% higher (p\u3c0.01) in the old as compared to the young women, bone sclerostin mRNA levels were no different between the two groups (p=0.845). However, genes related to notch signaling were significantly upregulated (p=0.003 when analyzed as a group) in the biopsies from the old women. In an additional analysis of 118 genes including those from genome-wide association studies related to bone density and/or fracture, BMP/TGFβ family genes, selected growth factors and nuclear receptors, and Wnt/Wnt-related genes, we found that mRNA levels of the Wnt inhibitor, SFRP1, were significantly increased (by 1.6-fold, p=0.0004, false discovery rate [q]=0.04) in the biopsies from the old as compared to the young women. Our findings thus indicate that despite increases in circulating sclerostin levels, bone sclerostin mRNA levels do not increase in elderly women. However, aging is associated with alterations in several key pathways and genes in humans that may contribute to the observed impairment in bone formation. These include notch signaling, which represents a potential therapeutic target for increasing bone formation in humans. Our studies further identified mRNA levels of SFRP1 as being increased in aging bone in humans, suggesting that this may also represent a viable target for the development of anabolic therapies for age-related bone loss and osteoporosis

Effects of estrogen on bone mRNA levels of sclerostin and other genes relevant to bone metabolism in postmenopausal women

Context: Studies in postmenopausal women have shown that estrogen reduces circulating sclerostin levels, but effects of estrogen on skeletal sclerostin mRNA levels are unknown.Objective: The objective of the study was to evaluate the effects of short-term estrogen treatment on bone mRNA levels of sclerostin and other genes relevant to bone metabolism.Design, setting, and patients: Needle bone biopsies were obtained from 20 postmenopausal women treated with transdermal estrogen for 3 weeks and 20 untreated controls. Quantitative PCR analyses were used to examine the expression of sclerostin and other genes related to bone metabolism, including 71 additional genes linked to bone density/fracture from genome-wide association studies.Results: Estrogen treatment was associated with lower bone sclerostin mRNA levels (by 48%, P\u3c.05) and with lower (by 54%, P\u3c.01) mRNA levels of the sclerostin-related protein, sclerostin domain-containing protein 1 (SOSTDC1), which is also a Wnt/bone morphogenetic protein inhibitor. Consistent with studies in mice showing that ovariectomy increased nuclear factor-κB (NF-κB) activation, we found that estrogen treatment was associated with a significant reduction in inflammatory genes as a group (P=.028), with bone mRNA levels of NFKB2 and RELB (both encoding proteins in the NF-κB transcription factor complex) being significantly reduced individual genes. Eight of the 71 genome-wide association study-related genes examined were modulated by estrogen (P\u3c.05, false discovery rate\u3c0.10).Conclusion: In humans, estrogen-induced decreases in two key inhibitors of Wnt/bone morphogenetic protein signaling, sclerostin and SOSTDC1, along with reductions in NF-κB signaling, may be responsible for at least part of the protective effects of estrogen on bone

Phase 1/2 Study of Lumasiran for Treatment of Primary Hyperoxaluria Type 1: A Placebo-Controlled Randomized Clinical Trial

BACKGROUND AND OBJECTIVES: In the rare disease primary hyperoxaluria type 1, overproduction of oxalate by the liver causes kidney stones, nephrocalcinosis, kidney failure, and systemic oxalosis. Lumasiran, an RNA interference therapeutic, suppresses glycolate oxidase, reducing hepatic oxalate production. The objective of this first-in-human, randomized, placebo-controlled trial was to evaluate the safety, pharmacokinetic, and pharmacodynamic profiles of lumasiran in healthy participants and patients with primary hyperoxaluria type 1. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This phase 1/2 study was conducted in two parts. In part A, healthy adults randomized 3:1 received a single subcutaneous dose of lumasiran or placebo in ascending dose groups (0.3-6 mg/kg). In part B, patients with primary hyperoxaluria type 1 randomized 3:1 received up to three doses of lumasiran or placebo in cohorts of 1 or 3 mg/kg monthly or 3 mg/kg quarterly. Patients initially assigned to placebo crossed over to lumasiran on day 85. The primary outcome was incidence of adverse events. Secondary outcomes included pharmacokinetic and pharmacodynamic parameters, including measures of oxalate in patients with primary hyperoxaluria type 1. Data were analyzed using descriptive statistics. RESULTS: Thirty-two healthy participants and 20 adult and pediatric patients with primary hyperoxaluria type 1 were enrolled. Lumasiran had an acceptable safety profile, with no serious adverse events or study discontinuations attributed to treatment. In part A, increases in mean plasma glycolate concentration, a measure of target engagement, were observed in healthy participants. In part B, patients with primary hyperoxaluria type 1 had a mean maximal reduction from baseline of 75% across dosing cohorts in 24-hour urinary oxalate excretion. All patients achieved urinary oxalate levels ≤1.5 times the upper limit of normal. CONCLUSIONS: Lumasiran had an acceptable safety profile and reduced urinary oxalate excretion in all patients with primary hyperoxaluria type 1 to near-normal levels. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Study of Lumasiran in Healthy Adults and Patients with Primary Hyperoxaluria Type 1, NCT02706886