D3/Penta 21 clinical trial design: A randomised non-inferiority trial with nested drug licensing substudy to assess dolutegravir and lamivudine fixed dose formulations for the maintenance of virological suppression in children with HIV-1 infection, aged 2 to 15 years.

BACKGROUND: There is increasing interest in utilising two-drug regimens for HIV treatment with the goal of reducing toxicity and improve acceptability. The D3 trial evaluates the efficacy and safety of DTG/3TC in children and adolescents and includes a nested pharmacokinetics(PK) substudy for paediatric drug licensing. METHODS: D3 is an ongoing open-label, phase III, 96-week non-inferiority randomised controlled trial(RCT) conducted in South Africa, Spain, Thailand, Uganda and the United Kingdom. D3 has enrolled 386 children aged 2- < 15 years, virologically suppressed for ≥6 months, with no prior treatment failure. Participants were randomised 1:1 to receive DTG/3TC or DTG plus two nucleoside reverse transcriptase inhibitors(NRTIs), stratified by region, age (2- < 6, 6- < 12, 12- < 15 years) and DTG use at enrolment (participants permitted to start DTG at enrolment). The primary outcome is confirmed HIV-1 RNA viral rebound ≥50 copies/mL by 96-weeks. The trial employs the Smooth Away From Expected(SAFE) non-inferiority frontier, which specifies the non-inferiority margin and significance level based on the observed event risk in the control arm. The nested PK substudy evaluates WHO weight-band-aligned dosing in the DTG/3TC arm. DISCUSSION: D3 is the first comparative trial evaluating DTG/3TC in children and adolescents. Implications of integrating a PK substudy and supplying data for prompt regulatory submission, were carefully considered to ensure the integrity of the ongoing trial. The trial uses an innovative non-inferiority frontier for the primary analysis to allow for a lower-than-expected confirmed viral rebound risk in the control arm, while ensuring interpretability of results and maintaining the planned sample size in an already funded trial. TRIAL REGISTRATION: International Standard Randomised Clinical Trial Number Register: ISRCTN17157458. European Clinical Trials Database: 2020-001426-57. CLINICALTRIALS: gov: NCT04337450.

Simultaneous pharmacokinetic modeling of unbound and total darunavir with ritonavir in adolescents: a substudy of the SMILE trial.

Darunavir (DRV) is an HIV protease inhibitor commonly used as part of antiretroviral treatment regimens globally for children and adolescents. It requires a pharmacological booster, such as ritonavir (RTV) or cobicistat. To better understand the pharmacokinetics (PK) of DRV in this younger population and the importance of the RTV boosting effect, a population PK substudy was conducted within SMILE trial, where the maintenance of HIV suppression with once daily integrate inhibitor + darunavir/ritonavir in children and adolescents is evaluated. A joint population PK model that simultaneously used total DRV, unbound DRV, and total RTV concentrations was developed. Competitive and non-competitive models were examined to define RTV's influence on DRV pharmacokinetics. Linear and non-linear equations were tested to assess DRV protein binding. A total of 443 plasma samples from 152 adolescents were included in this analysis. Darunavir PK was best described by a one-compartment model first-order absorption and elimination. The influence of RTV on DRV pharmacokinetics was best characterized by ritonavir area under the curve on DRV clearance using a power function. The association of non-linear and linear equations was used to describe DRV protein binding to alpha-1 glycoprotein and albumin, respectively. In our population, simulations indicate that 86.8% of total and unbound DRV trough concentrations were above 0.55 mg/L [10 times protein binding-adjusted EC50 for wild-type (WT) HIV-1] and 0.0243 mg/L (10 times EC90 for WT HIV-1) targets, respectively. Predictions were also in agreement with observed outcomes from adults receiving 800/100 mg DRV/r once a day. Administration of 800/100 mg of DRV/r once daily provides satisfactory concentrations and exposures for adolescents aged 12 years and older.

Nucleoside/nucleotide reverse transcriptase inhibitor sparing regimen with once daily integrase inhibitor plus boosted darunavir is non-inferior to standard of care in virologically-suppressed children and adolescents living with HIV - Week 48 results of the randomised SMILE Penta-17-ANRS 152 clinical trial.

Background: Integrase inhibitor (INSTI) with boosted darunavir (DRV/r), a regimen with a high-resistance barrier, avoiding NRTI toxicities, might be a switching option in children living with HIV (CLWHIV). Methods: SMILE is a randomised non-inferiority trial evaluating safety and antiviral efficacy of once-daily INSTI + DRV/r vs. continuing on current standard-of-care (SOC) triple ART (2NRTI + boosted PI/NNRTI) in virologically-suppressed CLWHIV aged 6-18 years. The primary outcome is the proportion with confirmed HIV-RNA ≥50 copies/mL by week 48, estimated by Kaplan-Meier method. Non-inferiority margin was 10%. Registration number for SMILE are: ISRCTN11193709, NCT #: NCT02383108. Findings: Between 10th June 2016 and 30th August 2019, 318 participants were enrolled from Africa 53%, Europe 24%, Thailand 15% and Latin America 8%, 158 INSTI + DRV/r [153 Dolutegravir (DTG); 5 Elvitegravir (EVG)], 160 SOC. Median (range) age was 14.7 years (7.6-18.0); CD4 count 782 cells/mm3 (227-1647); 61% female. Median follow-up was 64.3 weeks with no loss to follow-up. By 48 weeks, 8 INSTI + DRV/r vs. 12 SOC had confirmed HIV-RNA ≥50 copies/mL; difference (INSTI + DRV/r-SOC) -2.5% (95% CI: -7.6, 2.5%), showing non-inferiority. No major PI or INSTI resistance mutations were observed. There were no differences in safety between arms. By week 48, difference (INSTI + DRV/r-SOC) in mean CD4 count change from baseline was -48.3 cells/mm3 (95% CI: -93.4, -3.2; p = 0.036). Difference (INSTI + DRV/r-SOC) in mean HDL change from baseline was -4.1 mg/dL (95% CI: -6.7, -1.4; p = 0.003). Weight and Body Mass Index (BMI) increased more in INSTI + DRV/r than SOC [difference: 1.97 kg (95% CI: 1.1, 2.9; p < 0.001), 0.66 kg/m2 (95% CI: 0.3, 1.0; p < 0.001)]. Interpretation: In virologically-suppressed children, switching to INSTI + DRV/r was non-inferior virologically, with similar safety profile, to continuing SOC. Small but significant differences in CD4, HDL-cholesterol, weight and BMI were observed between INSTI + DRV/r vs. SOC although clinical relevance needs further investigation. SMILE data corroborate adult findings and provide evidence for this NRTI-sparing regimen for children and adolescents. Funding: Fondazione Penta Onlus, Gilead, Janssen, INSERM/ANRS and UK MRC. ViiV-Healthcare provided Dolutegravir.

Dolutegravir twice-daily dosing in children with HIV-associated tuberculosis: a pharmacokinetic and safety study within the open-label, multicentre, randomised, non-inferiority ODYSSEY trial.

BACKGROUND: Children with HIV-associated tuberculosis (TB) have few antiretroviral therapy (ART) options. We aimed to evaluate the safety and pharmacokinetics of dolutegravir twice-daily dosing in children receiving rifampicin for HIV-associated TB. METHODS: We nested a two-period, fixed-order pharmacokinetic substudy within the open-label, multicentre, randomised, controlled, non-inferiority ODYSSEY trial at research centres in South Africa, Uganda, and Zimbabwe. Children (aged 4 weeks to <18 years) with HIV-associated TB who were receiving rifampicin and twice-daily dolutegravir were eligible for inclusion. We did a 12-h pharmacokinetic profile on rifampicin and twice-daily dolutegravir and a 24-h profile on once-daily dolutegravir. Geometric mean ratios for trough plasma concentration (Ctrough), area under the plasma concentration time curve from 0 h to 24 h after dosing (AUC0-24 h), and maximum plasma concentration (Cmax) were used to compare dolutegravir concentrations between substudy days. We assessed rifampicin Cmax on the first substudy day. All children within ODYSSEY with HIV-associated TB who received rifampicin and twice-daily dolutegravir were included in the safety analysis. We described adverse events reported from starting twice-daily dolutegravir to 30 days after returning to once-daily dolutegravir. This trial is registered with ClinicalTrials.gov (NCT02259127), EudraCT (2014-002632-14), and the ISRCTN registry (ISRCTN91737921). FINDINGS: Between Sept 20, 2016, and June 28, 2021, 37 children with HIV-associated TB (median age 11·9 years [range 0·4-17·6], 19 [51%] were female and 18 [49%] were male, 36 [97%] in Africa and one [3%] in Thailand) received rifampicin with twice-daily dolutegravir and were included in the safety analysis. 20 (54%) of 37 children enrolled in the pharmacokinetic substudy, 14 of whom contributed at least one evaluable pharmacokinetic curve for dolutegravir, including 12 who had within-participant comparisons. Geometric mean ratios for rifampicin and twice-daily dolutegravir versus once-daily dolutegravir were 1·51 (90% CI 1·08-2·11) for Ctrough, 1·23 (0·99-1·53) for AUC0-24 h, and 0·94 (0·76-1·16) for Cmax. Individual dolutegravir Ctrough concentrations were higher than the 90% effective concentration (ie, 0·32 mg/L) in all children receiving rifampicin and twice-daily dolutegravir. Of 18 children with evaluable rifampicin concentrations, 15 (83%) had a Cmax of less than the optimal target concentration of 8 mg/L. Rifampicin geometric mean Cmax was 5·1 mg/L (coefficient of variation 71%). During a median follow-up of 31 weeks (IQR 30-40), 15 grade 3 or higher adverse events occurred among 11 (30%) of 37 children, ten serious adverse events occurred among eight (22%) children, including two deaths (one tuberculosis-related death, one death due to traumatic injury); no adverse events, including deaths, were considered related to dolutegravir. INTERPRETATION: Twice-daily dolutegravir was shown to be safe and sufficient to overcome the rifampicin enzyme-inducing effect in children, and could provide a practical ART option for children with HIV-associated TB. FUNDING: Penta Foundation, ViiV Healthcare, UK Medical Research Council.

Dolutegravir dosing for children with HIV weighing less than 20 kg: pharmacokinetic and safety substudies nested in the open-label, multicentre, randomised, non-inferiority ODYSSEY trial.

BACKGROUND: Dolutegravir-based antiretroviral therapy is a preferred first-line treatment for adults and children living with HIV; however, very little pharmacokinetic data for dolutegravir use are available in young children. We therefore aimed to evaluate dolutegravir dosing and safety in children weighing 3 kg to less than 20 kg by assessing pharmacokinetic parameters and safety data in children taking dolutegravir within the ODYSSEY trial. METHODS: We did pharmacokinetic substudies nested within the open-label, multicentre, randomised, non-inferiority ODYSSEY trial. We enrolled children from seven research centres in South Africa, Uganda, and Zimbabwe. Children weighing 3 kg to less than 14 kg received 5 mg dispersible tablets of dolutegravir according to WHO weight bands: 5 mg for children weighing 3 kg to less than 6 kg and younger than 6 months, 10 mg for children weighing 3 kg to less than 6 kg and aged 6 months or older, 15 mg for children weighing 6 kg to less than 10 kg, and 20 mg for children weighing 10 kg to less than 14 kg. Children weighing 14 kg to less than 20 kg received a 25 mg film-coated tablet once per day early in the trial or 25 mg dispersible tablets (five 5 mg tablets once per day) later in the trial. A minimum of eight children per weight band or dose was targeted for 24 h pharmacokinetic profiling at steady state. The primary pharmacokinetic parameter was the trough concentration 24 h after observed dolutegravir intake (Ctrough). Pharmacokinetic targets were based on adult dolutegravir Ctrough and the 90% effective concentration (EC90; ie, 0·32 mg/L). Safety was evaluated in eligible children consenting to pharmacokinetic substudies. FINDINGS: Between May 25, 2017, and Aug 15, 2019, we enrolled 72 children aged between 3 months and 11 years. 71 children were included in the safety population and 55 (76%) of 72 children contributed 65 evaluable pharmacokinetic profiles. Geometric mean Ctrough in children on dispersible tablets in weight bands between 3 kg and less than 20 kg ranged between 0·53-0·87 mg/L, comparable to the adult geometric mean Ctrough of 0·83 mg/L. Variability was high with coefficient of variation percentages ranging between 50% and 150% compared with 26% in adults. Ctrough below EC90 was observed in four (31%) of 13 children weighing 6 kg to less than 10 kg taking 15 mg dispersible tablets, and four (21%) of 19 weighing 14 kg to less than 20 kg taking 25 mg film-coated tablets. The lowest geometric mean Ctrough of 0·44 mg/L was observed in children weighing 14 kg to less than 20 kg on 25 mg film-coated tablets. Exposures were 1·7-2·0 times higher on 25 mg dispersible tablets versus 25 mg film-coated tablets. 19 (27%) of 71 children had 29 reportable grade 3 or higher adverse events (13 serious adverse events, including two deaths), none of which were related to dolutegravir. INTERPRETATION: Weight-band dosing of paediatric dolutegravir dispersible tablets provides appropriate drug exposure in most children weighing 3 kg to less than 20 kg, with no safety signal. 25 mg film-coated tablets did not achieve pharmacokinetic parameters in children weighing 14 kg to less than 20 kg, which were comparable to adults, suggesting dosing with dispersible tablets is preferable or a higher film-coated tablet dose is required. FUNDING: Paediatric European Network for Treatment of AIDS Foundation, ViiV Healthcare, and UK Medical Research Council.

Early ART-initiation and longer ART duration reduces HIV-1 proviral DNA levels in children from the CHER trial.

BACKGROUND: Reduction of the reservoir of latent HIV-infected cells might increase the possibility of long-term remission in individuals living with HIV. We investigated factors associated with HIV-1 proviral DNA levels in children receiving different antiretroviral therapy (ART) strategies in the children with HIV early antiretroviral therapy (CHER) trial. METHODS: Infants with HIV < 12 weeks old with CD4% ≥ 25% were randomized in the CHER trial to early limited ART for 40 or 96 weeks (ART-40 W, ART-96 W), or deferred ART (ART-Def). For ART-Def infants or following ART interruption in ART-40 W/ART-96 W, ART was started/re-started for clinical progression or CD4% < 25%. In 229 participants, HIV-1 proviral DNA was quantified by PCR from stored peripheral blood mononuclear cells from children who had received ≥ 24 weeks ART and two consecutive undetectable HIV-1 RNA 12-24 weeks apart. HIV-1 proviral DNA was compared between ART-Def and ART-96 W at week 96, and in all arms at week 248. Factors associated with HIV-1 proviral DNA levels were evaluated using linear regression. FINDINGS: Longer duration of ART was significantly associated with lower HIV-1 proviral DNA at both 96 (p = 0.0003) and 248 weeks (p = 0.0011). Higher total CD8 count at ART initiation was associated with lower HIV-1 proviral DNA at both 96 (p = 0.0225) and 248 weeks (p = 0.0398). Week 248 HIV-1 proviral DNA was significantly higher in those with positive HIV-1 serology at week 84 than those with negative serology (p = 0.0042). INTEPRETATION: Longer ART duration is key to HIV-1 proviral DNA reduction. Further understanding is needed of the effects of "immune-attenuation" through early HIV-1 exposure. FUNDING: Wellcome Trust, National Institutes of Health, Medical Research Council.

Associations between SNPs and immune-related circulating proteins in schizophrenia.

Genome-wide association studies (GWAS) and proteomic studies have provided convincing evidence implicating alterations in immune/inflammatory processes in schizophrenia. However, despite the convergence of evidence, direct links between the genetic and proteomic findings are still lacking for schizophrenia. We investigated associations between single nucleotide polymorphisms (SNPs) from the custom-made PsychArray and the expression levels of 190 multiplex immunoassay profiled serum proteins in 149 schizophrenia patients and 198 matched controls. We identified associations between 81 SNPs and 29 proteins, primarily involved in immune/inflammation responses. Significant SNPxDiagnosis interactions were identified for eight serum proteins including Factor-VII[rs555212], Alpha-1-Antitrypsin[rs11846959], Interferon-Gamma Induced Protein 10[rs4256246] and von-Willebrand-Factor[rs12829220] in the control group; Chromogranin-A[rs9658644], Cystatin-C[rs2424577] and Vitamin K-Dependent Protein S[rs6123] in the schizophrenia group; Interleukin-6 receptor[rs7553796] in both the control and schizophrenia groups. These results suggested that the effect of these SNPs on expression of the respective proteins varies with diagnosis. The combination of patient-specific genetic information with blood biomarker data opens a novel approach to investigate disease mechanisms in schizophrenia and other psychiatric disorders. Our findings not only suggest that blood protein expression is influenced by polymorphisms in the corresponding gene, but also that the effect of certain SNPs on expression of proteins can vary with diagnosis.

Blood-based immune-endocrine biomarkers of treatment response in depression.

Antidepressant treatment for major depressive disorder remains suboptimal with response rates of just over 50%. Although treatment guidelines, algorithms and clinical keys are available to assist the clinician, the process of finding an effective pharmacotherapy to maximise benefit for the individual patient is largely by "trial and error" and remains challenging. This highlights a clear need to identify biomarkers of treatment response to help guide personalised treatment strategies. We have carried out the largest multiplex immunoassay based longitudinal study to date, examining up to 258 serum markers involved in immune, endocrine and metabolic processes as potential biomarkers associated with treatment response in 332 depression patients recruited from four independent clinical centres. We demonstrated for the first time that circulating Apolipoprotein A-IV, Endoglin, Intercellular Adhesion Molecule 1, Tissue Inhibitor of Metalloproteinases 1, Plasminogen Activator Inhibitor 1, Thrombopoietin, Complement C3, Hepatocyte Growth Factor and Insulin-like Growth Factor-Binding Protein 2 were associated with response to different antidepressants. In addition, we showed that specific sets of immune-endocrine proteins were associated with response to Venlafaxine (serotonin-norepinephrine reuptake inhibitor), Imipramine (tricyclic antidepressant) and other antidepressant drugs. However, we were not able to reproduce the literature findings on BDNF and TNF-α, two of the most commonly reported candidate treatment response markers. Despite the need for extensive validation studies, our preliminary findings suggest that a pre-treatment immune-endocrine profile may help to determine a patient's likelihood to respond to specific antidepressant and/or alternative treatments such as anti-inflammatory drugs, providing hope for future personalised treatment approaches.

Molecular serum signature of treatment resistant depression.

RATIONALE: A substantial number of patients suffering from major depressive disorder (MDD) do not respond to multiple trials of anti-depressants, develop a chronic course of disease and become treatment resistant. Most of the studies investigating molecular changes in treatment-resistant depression (TRD) have only examined a limited number of molecules and genes. Consequently, biomarkers associated with TRD are still lacking. OBJECTIVES: This study aimed to use recently advanced high-throughput proteomic platforms to identify peripheral biomarkers of TRD defined by two staging models, the Thase and Rush staging model (TRM) and the Maudsley Staging Model (MSM). METHODS: Serum collected from an inpatient cohort of 65 individuals suffering from MDD was analysed using two different mass spectrometric-based platforms, label-free liquid chromatography mass spectrometry (LC-MS(E)) and selective reaction monitoring (SRM), as well as a multiplex bead based assay. RESULTS: In the LC-MS(E) analysis, proteins involved in the acute phase response and complement activation and coagulation were significantly different between the staging groups in both models. In the multiplex bead-based assay analysis TNF-α levels (log(odds) = -4.95, p = 0.045) were significantly different in the TRM comparison. Using SRM, significant changes of three apolipoproteins A-I (ß = 0.029, p = 0.035), M (ß = -0.017, p = 0.009) and F (ß = -0.031, p = 0.024) were associated with the TRM but not the MSM. CONCLUSION: Overall, our findings suggest that proteins, which are involved in immune and complement activation, may represent potential biomarkers that could be used by clinicians to identify high-risk patients. Nevertheless, given that the molecular changes between the staging groups were subtle, the results need to be interpreted cautiously.

Identification of an Immune-Neuroendocrine Biomarker Panel for Detection of Depression: A Joint Effects Statistical Approach.

BACKGROUND/AIMS: Less than half of depression patients are correctly diagnosed within the primary care setting. Previous proteomic studies have identified numerous immune and neuroendocrine changes in patients. However, few studies have considered the joint effects of biological molecules and their diagnostic potential. Our aim was to develop and validate a diagnostic serum biomarker panel identified through joint effects analysis of multiplex immunoassay profiling data from 1,007 clinical samples. METHODS: In stage 1, we conducted a meta-analysis of two independent cohorts of 78 first-/recent-onset drug-naive/drug-free depression patients and 156 controls and applied the 10-fold cross-validation with least absolute shrinkage and selection operator regression to identify an optimal diagnostic prediction model (biomarker panel). In stage 2, we tested the discriminatory performance of this biomarker panel using the naturalistic Netherlands Study of Depression and Anxiety (NESDA) cohort of 468 depression patients and 305 controls. RESULTS: An optimal panel of 33 immune-neuroendocrine biomarkers and gender was selected in the meta-analysis. Testing this biomarker-gender panel using the NESDA cohort resulted in a moderate to good performance to differentiate patients from controls (0.69 < AUC < 0.86), particularly the first-episode patients free of chronic non-psychiatric diseases or medications and following incorporation of sociodemographic covariates (0.76 < AUC < 0.92). CONCLUSION: Despite the need for additional validation studies, we demonstrated that a blood-based biomarker-sociodemographic panel can detect depression in naturalistic healthcare settings with good discriminatory power. Further refinements of blood biomarker panels aiding in the diagnosis of depression may provide a cost-effective means to increase accuracy of clinical diagnosis within the primary care setting.

Commercialisation of Biomarker Tests for Mental Illnesses: Advances and Obstacles.

Substantial strides have been made in the field of biomarker research for mental illnesses over the past few decades. However, no US FDA-cleared blood-based biomarker tests have been translated into routine clinical practice. Here, we review the challenges associated with commercialisation of research findings and discuss how these challenges can impede scientific impact and progress. Overall evidence indicates that a lack of research funding and poor reproducibility of findings were the most important obstacles to commercialization of biomarker tests. Fraud, pre-analytical and analytical limitations, and inappropriate statistical analysis are major contributors to poor reproducibility. Increasingly, these issues are acknowledged and actions are being taken to improve data validity, raising the hope that robust biomarker tests will become available in the foreseeable future.

The potential of immune biomarkers to advance personalized medicine approaches for schizophrenia.

Molecular profiling studies have helped increase the understanding of the immune processes thought to be involved in the etiology and pathophysiology of psychiatric disorders such as schizophrenia. Current therapeutic interventions with first- and second-generation antipsychotics are suboptimal. Poor response rates and debilitating side effects often lead to poor treatment compliance. This highlights the pressing need to identify more effective treatments as well as objective biomarker based tests, which can help predict treatment response and identify diagnostic subpopulations. Such tests could enable early detection of patients who will benefit from particular therapeutic interventions. In this review, we discuss studies relating to dysfunctions of the immune system in patients with schizophrenia and the effects of antipsychotic medication on the molecular components of these systems. Immune system dysfunction may in part be related to genetic risk factors for schizophrenia, but there is substantial evidence that a wide range of environmental factors ranging from exposure to infectious agents such as influenza and Toxoplasma gondii to HPA axis dysfunction play an important role in the etiopathogenesis of schizophrenia. Ongoing research efforts, testing therapeutic efficacy of anti-inflammatory agents used as add-on medications are also discussed. From a therapeutic perspective, these represent the initial steps toward novel treatment approaches and more effective patient care in the field of mental health.

Distinct proteomic profiles in post-mortem pituitary glands from bipolar disorder and major depressive disorder patients.

Disturbances of the hypothalamic-pituitary-adrenal axis have been implicated in the pathophysiology of bipolar disorder (BD) and major depressive disorder (MDD). To examine this further, we carried out proteomic profiling of post-mortem pituitaries from 13 BD and 14 MDD patients, in comparison to 15 controls. Liquid chromatography-mass spectrometry (LC-MS(E)) analysis showed that BD patients had significantly increased levels of the major pituitary hormones pro-opiomelanocortin (POMC) and galanin. BD patients also showed changes in proteins associated with gene transcription, stress response, lipid metabolism and growth signalling. In contrast, LC-MS(E) profiling revealed that MDD patients had significantly decreased levels of the prohormone-converting enzyme carboxypeptidease E and follow-up enzymatic analysis showed decreased activity of prolyl-oligopeptidase convertase. This suggested that altered prohormone processing may occur in pituitaries of MDD patients. In addition, MDD patients had significant changes in proteins involved in intracellular transport and cytoskeletal signalling. Finally, we carried out selective reaction monitoring (SRM) mass spectrometry profiling for validation of protein changes in key biological pathways. This confirmed increased POMC levels in BD patients with no change in the levels of this prohormone in MDD. This study demonstrates that proteomic profiling analysis of the pituitary can lead to new insights into the pathophysiology of BD and MDD. Also, given that the pituitary directly releases a variety of bioactive molecules into the bloodstream, many of the proteins identified here could serve as focal points in the search for peripheral biomarkers in clinical or drug treatment studies of BD and MDD patients.

Applications of blood-based protein biomarker strategies in the study of psychiatric disorders.

Major psychiatric disorders such as schizophrenia, major depressive and bipolar disorders are severe, chronic and debilitating, and are associated with high disease burden and healthcare costs. Currently, diagnoses of these disorders rely on interview-based assessments of subjective self-reported symptoms. Early diagnosis is difficult, misdiagnosis is a frequent occurrence and there are no objective tests that aid in the prediction of individual responses to treatment. Consequently, validated biomarkers are urgently needed to help address these unmet clinical needs. Historically, psychiatric disorders are viewed as brain disorders and consequently only a few researchers have as yet evaluated systemic changes in psychiatric patients. However, promising research has begun to challenge this concept and there is an increasing awareness that disease-related changes can be traced in the peripheral system which may even be involved in the precipitation of disease onset and course. Converging evidence from molecular profiling analysis of blood serum/plasma have revealed robust molecular changes in psychiatric patients, suggesting that these disorders may be detectable in other systems of the body such as the circulating blood. In this review, we discuss the current clinical needs in psychiatry, highlight the importance of biomarkers in the field, and review a representative selection of biomarker studies to highlight opportunities for the implementation of personalized medicine approaches in the field of psychiatry. It is anticipated that the implementation of validated biomarker tests will not only improve the diagnosis and more effective treatment of psychiatric patients, but also improve prognosis and disease outcome.

Proteomic changes in serum of first onset, antidepressant drug-naïve major depression patients.

Major depressive disorder (MDD) is a complex and multi-factorial disorder. Although genetic factors and other molecular aspects of MDD have been widely studied, the underlying pathological mechanisms are still mostly unknown. We sought to investigate the pathophysiology of MDD by identifying and characterising serum molecular differences and their correlation to symptom severity in first onset, antidepressant drug-naïve MDD patients. We performed an exploratory molecular profiling study on serum samples of MDD patients and controls using multiplex immunoassay and label-free liquid chromatography mass spectrometry in data independent mode (LC-MSE). We included two independent cohorts of first onset, antidepressant drug-naïve MDD patients (n = 23 and 15) and matched controls (n = 42 and 21) in our study in order to validate the results. The main outcome included the following list of circulatory molecules changing and/or correlating to symptom severity: angiotensin-converting enzyme, acute phase proteins (e.g. ferritin and serotransferrin), brain-derived neurotrophic factor, complement component C4-B, cortisol, cytokines (e.g. macrophage migration inhibitory factor and interleukin-16), extracellular newly identified receptor for advanced glycosylation end products-binding protein, growth hormone and superoxide dismutase-1. This study provides evidence of an increased pro-inflammatory and oxidative stress response, followed by a hyperactivation of the HPA-axis in the acute stages of first onset MDD, as well as a dysregulation in growth factor pathways. These findings help to elucidate MDD related pathways in more detail and further studies may lead to identification of novel drug targets, including components of the inflammatory and oxidative stress response.

The use of proteomic biomarkers for improved diagnosis and stratification of schizophrenia patients.

Schizophrenia is characterized by a wide spectrum of clinical manifestations, including strong effects on mood and behavior. Patients can also suffer from serious comorbidities including immune system or metabolic abnormalities. Recent advances using proteomic profiling approaches have increased our understanding of these molecular effects and have laid the groundwork for unraveling the heterogeneity of this broadly defined disease. These findings could lead to improved diagnosis and stratification of patients through identification of biochemically different disease subtypes and personalized medicine approaches. The inclusion of molecular signatures in psychiatry will be an important leap forward in providing more effective treatment of patients suffering from this debilitating disorder.

A combined metabonomic and proteomic approach identifies frontal cortex changes in a chronic phencyclidine rat model in relation to human schizophrenia brain pathology.

Current schizophrenia (SCZ) treatments fail to treat the broad range of manifestations associated with this devastating disorder. Thus, new translational models that reproduce the core pathological features are urgently needed to facilitate novel drug discovery efforts. Here, we report findings from the first comprehensive label-free liquid-mass spectrometry proteomic- and proton nuclear magnetic resonance-based metabonomic profiling of the rat frontal cortex after chronic phencyclidine (PCP) intervention, which induces SCZ-like symptoms. The findings were compared with results from a proteomic profiling of post-mortem prefrontal cortex from SCZ patients and with relevant findings in the literature. Through this approach, we identified proteomic alterations in glutamate-mediated Ca(2+) signaling (Ca(2+)/calmodulin-dependent protein kinase II, PPP3CA, and VISL1), mitochondrial function (GOT2 and PKLR), and cytoskeletal remodeling (ARP3). Metabonomic profiling revealed changes in the levels of glutamate, glutamine, glycine, pyruvate, and the Ca(2+) regulator taurine. Effects on similar pathways were also identified in the prefrontal cortex tissue from human SCZ subjects. The discovery of similar but not identical proteomic and metabonomic alterations in the chronic PCP rat model and human brain indicates that this model recapitulates only some of the molecular alterations of the disease. This knowledge may be helpful in understanding mechanisms underlying psychosis, which, in turn, can facilitate improved therapy and drug discovery for SCZ and other psychiatric diseases. Most importantly, these molecular findings suggest that the combined use of multiple models may be required for more effective translation to studies of human SCZ.

Structure of the arginine methyltransferase PRMT5-MEP50 reveals a mechanism for substrate specificity.

The arginine methyltransferase PRMT5-MEP50 is required for embryogenesis and is misregulated in many cancers. PRMT5 targets a wide variety of substrates, including histone proteins involved in specifying an epigenetic code. However, the mechanism by which PRMT5 utilizes MEP50 to discriminate substrates and to specifically methylate target arginines is unclear. To test a model in which MEP50 is critical for substrate recognition and orientation, we determined the crystal structure of Xenopus laevis PRMT5-MEP50 complexed with S-adenosylhomocysteine (SAH). PRMT5-MEP50 forms an unusual tetramer of heterodimers with substantial surface negative charge. MEP50 is required for PRMT5-catalyzed histone H2A and H4 methyltransferase activity and binds substrates independently. The PRMT5 catalytic site is oriented towards the cross-dimer paired MEP50. Histone peptide arrays and solution assays demonstrate that PRMT5-MEP50 activity is inhibited by substrate phosphorylation and enhanced by substrate acetylation. Electron microscopy and reconstruction showed substrate centered on MEP50. These data support a mechanism in which MEP50 binds substrate and stimulates PRMT5 activity modulated by substrate post-translational modifications.