Protocol for scarless genome editing of human pluripotent stem cell based on orthogonal selective reporters.

Human pluripotent stem cells (hPSCs) hold great promise for applications in regenerative medicine and disease modeling. Here, we present a protocol for establishing edited hPSC cell lines utilizing visualized orthogonal selective reporters. We describe steps for constructing plasmids, carrying out cell culture and electroporation, as well as performing drug-fluorescent dual enrichment, clone screening, and cell line characterization. This protocol facilitates the achievement of single-base homozygous mutations and reporter knockins, offering a reliable approach for precision genome editing.

Single-Nucleus Multiomic Analyses Identifies Gene Regulatory Dynamics of Phenotypic Modulation in Human Aneurysmal Aortic Root.

Aortic root aneurysm is a potentially life-threatening condition that may lead to aortic rupture and is often associated with genetic syndromes, such as Marfan syndrome (MFS). Although studies with MFS animal models have provided valuable insights into the pathogenesis of aortic root aneurysms, this understanding of the transcriptomic and epigenomic landscape in human aortic root tissue remains incomplete. This knowledge gap has impeded the development of effective targeted therapies. Here, this study performs the first integrative analysis of single-nucleus multiomic (gene expression and chromatin accessibility) and spatial transcriptomic sequencing data of human aortic root tissue under healthy and MFS conditions. Cell-type-specific transcriptomic and cis-regulatory profiles in the human aortic root are identified. Regulatory and spatial dynamics during phenotypic modulation of vascular smooth muscle cells (VSMCs), the cardinal cell type, are delineated. Moreover, candidate key regulators driving the phenotypic modulation of VSMC, such as FOXN3, TEAD1, BACH2, and BACH1, are identified. In vitro experiments demonstrate that FOXN3 functions as a novel key regulator for maintaining the contractile phenotype of human aortic VSMCs through targeting ACTA2. These findings provide novel insights into the regulatory and spatial dynamics during phenotypic modulation in the aneurysmal aortic root of humans.

Machine learning: Predicting hospital length of stay in patients admitted for lupus flares.

BACKGROUND: Although rare, severe systemic lupus erythematosus (SLE) flares requiring hospitalization account for most of the direct costs of SLE care. New machine learning (ML) methods may optimize lupus care by predicting which patients will have a prolonged hospital length of stay (LOS). Our study uses a machine learning approach to predict the LOS in patients admitted for lupus flares and assesses which features prolong LOS. METHODS: Our study sampled 5831 patients admitted for lupus flares from the National Inpatient Sample Database 2016-2018 and collected 90 demographics and comorbidity features. Four machine learning (ML) models were built (XGBoost, Linear Support Vector Machines, K Nearest Neighbors, and Logistic Regression) to predict LOS, and their performance was evaluated using multiple metrics, including accuracy, receiver operator area under the curve (ROC-AUC), precision-recall area under the curve (PR- AUC), and F1-score. Using the highest-performing model (XGBoost), we assessed the feature importance of our input features using Shapley value explanations (SHAP) to rank their impact on LOS. RESULTS: Our XGB model performed the best with a ROC-AUC of 0.87, PR-AUC of 0.61, an F1 score of 0.56, and an accuracy of 95%. The features with the most significant impact on the model were "the need for a central line," "acute dialysis," and "acute renal failure." Other top features include those related to renal and infectious comorbidities. CONCLUSION: Our results were consistent with the established literature and showed promise in ML over traditional methods of predictive analyses, even with rare rheumatic events such as lupus flare hospitalizations.

Endothelial FIS1 DeSUMOylation Protects Against Hypoxic Pulmonary Hypertension.

BACKGROUND: Hypoxia is a major cause and promoter of pulmonary hypertension (PH), a representative vascular remodeling disease with poor prognosis and high mortality. However, the mechanism underlying how pulmonary arterial system responds to hypoxic stress during PH remains unclear. Endothelial mitochondria are considered signaling organelles on oxygen tension. Results from previous clinical research and our studies suggested a potential role of posttranslational SUMOylation (small ubiquitin-like modifier modification) in endothelial mitochondria in hypoxia-related vasculopathy. METHODS: Chronic hypoxia mouse model and Sugen/hypoxia rat model were employed as PH animal models. Mitochondrial morphology and subcellular structure were determined by transmission electron and immunofluorescent microscopies. Mitochondrial metabolism was determined by mitochondrial oxygen consumption rate and extracellular acidification rate. SUMOylation and protein interaction were determined by immunoprecipitation. RESULTS: The involvement of SENP1 (sentrin-specific protease 1)-mediated SUMOylation in mitochondrial remodeling in the pulmonary endothelium was identified in clinical specimens of hypoxia-related PH and was verified in human pulmonary artery endothelial cells under hypoxia. Further analyses in clinical specimens, hypoxic rat and mouse PH models, and human pulmonary artery endothelial cells and human embryonic stem cell-derived endothelial cells revealed that short-term hypoxia-induced SENP1 translocation to endothelial mitochondria to regulate deSUMOylation (the reversible process of SUMOylation) of mitochondrial fission protein FIS1 (mitochondrial fission 1), which facilitated FIS1 assembling with fusion protein MFN2 (mitofusin 2) and mitochondrial gatekeeper VDAC1 (voltage-dependent anion channel 1), and the membrane tethering activity of MFN2 by enhancing its oligomerization. Consequently, FIS1 deSUMOylation maintained the mitochondrial integrity and endoplasmic reticulum-mitochondria calcium communication across mitochondrial-associated membranes, subsequently preserving pulmonary endothelial function and vascular homeostasis. In contrast, prolonged hypoxia disabled the FIS1 deSUMOylation by diminishing the availability of SENP1 in mitochondria via inducing miR (micro RNA)-138 and consequently resulted in mitochondrial dysfunction and metabolic reprogramming in pulmonary endothelium. Functionally, introduction of viral-packaged deSUMOylated FIS1 within pulmonary endothelium in mice improved pulmonary endothelial dysfunction and hypoxic PH development, while knock-in of SUMO (small ubiquitin-like modifier)-conjugated FIS1 in mice exaggerated the diseased cellular and tissue phenotypes. CONCLUSIONS: By maintaining endothelial mitochondrial homeostasis, deSUMOylation of FIS1 adaptively preserves pulmonary endothelial function against hypoxic stress and consequently protects against PH. The FIS1 deSUMOylation-SUMOylation transition in pulmonary endothelium is an intrinsic pathogenesis of hypoxic PH.

Endogenous retrovirus-derived enhancers confer the transcriptional regulation of human trophoblast syncytialization.

Endogenous retroviruses (ERVs) have been proposed as a driving force for the evolution of the mammalian placenta, however, the contribution of ERVs to placental development and the underlying regulatory mechanism remain largely elusive. A key process of placental development is the formation of multinucleated syncytiotrophoblasts (STBs) in direct contact with maternal blood, through which constitutes the maternal-fetal interface critical for nutrient allocation, hormone production and immunological modulation during pregnancy. We delineate that ERVs profoundly rewire the transcriptional program of trophoblast syncytialization. Here, we first determined the dynamic landscape of bivalent ERV-derived enhancers with dual occupancy of H3K27ac and H3K9me3 in human trophoblast stem cells (hTSCs). We further demonstrated that enhancers overlapping several ERV families tend to exhibit increased H3K27ac and reduced H3K9me3 occupancy in STBs relative to hTSCs. Particularly, bivalent enhancers derived from the Simiiformes-specific MER50 transposons were linked to a cluster of genes important for STB formation. Importantly, deletions of MER50 elements adjacent to several STB genes, including MFSD2A and TNFAIP2, significantly attenuated their expression concomitant to compromised syncytium formation. Together, we propose that ERV-derived enhancers, MER50 specifically, fine-tune the transcriptional networks accounting for human trophoblast syncytialization, which sheds light on a novel ERV-mediated regulatory mechanism underlying placental development.

Patient-specific and gene-corrected induced pluripotent stem cell-derived endothelial cells elucidate single-cell phenotype of pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension characterized by the preferential remodeling of the pulmonary venules. Hereditary PVOD is caused by biallelic variants of the EIF2AK4 gene. Three PVOD patients who carried the compound heterozygous variants of EIF2AK4 and two healthy controls were recruited and induced pluripotent stem cells (iPSCs) were generated from human peripheral blood mononuclear cells (PBMCs). The EIF2AK4 c.2965C>T variant (PVOD#1), c.3460A>T variant (PVOD#2), and c.4832_4833insAAAG variant (PVOD#3) were corrected by CRISPR-Cas9 in PVOD-iPSCs to generate isogenic controls and gene-corrected-iPSCs (GC-iPSCs). PVOD-iPSC-endothelial cells (ECs) exhibited a decrease in GCN2 protein and mRNA expression when compared with control and GC-ECs. PVOD-ECs exhibited an abnormal EC phenotype featured by excessive proliferation and angiogenesis. The abnormal phenotype of PVOD-ECs was normalized by protein kinase B inhibitors AZD5363 and MK2206. These findings help elucidate the underlying molecular mechanism of PVOD in humans and to identify promising therapeutic drugs for treating the disease.

Generation of functionally competent hepatic stellate cells from human stem cells to model liver fibrosis in vitro.

The detailed understanding of fibrogenesis has been hampered by a lack of important functional quiescence characteristics and an in vitro model to recapitulate hepatic stellate cell (HSC) activation. In our study, we establish robust endoderm- and mesoderm-sourced quiescent-like induced HSCs (iHSCs) derived from human pluripotent stem cells. Notably, iHSCs present features of mature HSCs, including accumulation of vitamin A in the lipid droplets and maintained quiescent features. In addition, iHSCs display a fibrogenic response and secrete collagen I in response to hepatoxicity caused by thioacetamide, acetaminophen, and hepatitis B and C virus infection. Antiviral therapy attenuated virally induced iHSC activation. Interestingly, endoderm- and mesoderm-derived iHSCs showed similar iHSC phenotypes. Therefore, we provide a novel and robust method to efficiently generate functional iHSCs from hESC and iPSC differentiation, which could be used as a model for hepatocyte toxicity prediction, anti-liver-fibrosis drug screening, and viral hepatitis-induced liver fibrosis.

Angiorganoid: vitalizing the organoid with blood vessels.

The emergence of the organoid simulates the native organs and this mini organ offers an excellent platform for probing multicellular interaction, disease modeling and drug discovery. Blood vessels constitute the instructive vascular niche which is indispensable for organ development, function and regeneration. Therefore, it is expected that the introduction of infiltrated blood vessels into the organoid might further pump vitality and credibility into the system. While the field is emerging and growing with new concepts and methodologies, this review aims at presenting various sources of vascular ingredients for constructing vascularized organoids and the paired methodology including de- and recellularization, bioprinting and microfluidics. Representative vascular organoids corresponding to specific tissues are also summarized and discussed to elaborate on the next generation of organoid development.

Application of computerized cognitive test battery in major depressive disorder: a narrative literature review.

BACKGROUND: Major depressive disorder (MDD) is a chronic and debilitating relapsing-remitting mood disorder, characterized by psychological, cognitive, and behavioral disturbances. The assessment of cognitive dysfunction in individuals with MDD has increasingly become a topic of concern in recent years. AIMS: To pool and compare the characteristics of various cognition evaluation tools. METHOD: Overview of recent research in application of computerized cognitive test battery in MDD. RESULTS: With recent technological advances in mobile health technologies and the ubiquity of smartphones, the use of traditional tools is no longer sufficient to monitor the dynamic changes of an individual's cognitive performance, which may be influenced by many factors, including, but not limited to, disease course and medications. Computerized tests have many advantages over traditional neuropsychological testing, chiefly in terms of time and cost savings, accurate recording of multiple response components, and the ability to automatically store and compare performance between testing sessions. In the following review, we summarized cognitive impairment characteristics of MDD, introduced traditional assessment tools of cognitive function in MDD, and reviewed the development of the current computerized cognitive test batteries for MDD. The comparisons among cognitive function evaluation tools were also performed. CONCLUSIONS: It is our belief that the improvement of existing novel computerized cognitive test batteries, the development of more comprehensive and easy-to-operate scales, verification techniques and multiple follow-up surveys among large sample populations may provide valuable clues for the evaluation and tracking of cognitive function in individuals with MDD.

Ecological momentary assessment of depressive symptoms using the mind.me application: Convergence with the Patient Health Questionnaire-9 (PHQ-9).

Ecological momentary assessment (EMA) for mental disorders, using application-based (app) technology capable of passive and ambient data collection, has been insufficiently evaluated and validated with rigorous, adequately-powered, high-quality studies. Herein, we sought to validate the mind.me application for the assessment of depressive symptoms in adults. Adults (ages 18-65) who self-identified as having clinically significant depressive symptoms [i.e. Patient Health Questionnaire 9 (PHQ-9) ≥ 5] utilized the mind.me app-a mobile phone technology that collects data passively and continuously, and is capable of integrating broad multimodal data [e.g., location variance (e.g. GPS), behavioural (e.g. social network activity), and communication data (e.g. SMS texting, phone calls)]. The primary outcome was predictive accuracy (i.e. convergent validity with depressive symptom measurement, as captured by the PHQ-9). 200 subjects were enrolled in the study (mean age 46 ± 12.71). The average PHQ-9 score was 12.8 ± 6.9. The predictive accuracy of the mind.me app was 0.91 ± 0.06. The sensitivity was 0.98 and the specificity was 0.93. The mind.me app was rated by 200 users as highly usable and informative to their illness. The mind.me app exhibits robust predictive accuracy in detecting depressive symptoms in adults with clinically relevant depressive symptoms. The mind.me app more specifically demonstrates convergence with the PHQ-9.

Dysregulation of kynurenine pathway and potential dynamic changes of kynurenine in schizophrenia: A systematic review and meta-analysis.

The kynurenine (KYN) pathway is postulated to play various roles in immune system dysregulation of schizophrenia (SCZ). We conducted a meta-analysis to explore the association between six key metabolites of KYN pathway (i.e., tryptophan (TRP), KYN, quinolinic acid (QUIN), and kynurenic acid (KYNA)) and SCZ. Priori Bonferroni adjustments were conducted for multiple comparisons. In total, 42 studies that examined the relationship between the metabolites in KYN pathway mentioned above and SCZ in 4217 participants and nine studies that examined alterations of these metabolites after antipsychotic treatments were included. The results demonstrate that (1) subjects with prescribed medication had significantly higher KYN levels when compared to controls; (2) higher KYN levels in cerebrospinal fluid (CSF), lower plasma KYN levels and higher CSF KYNA levels were associated with SCZ; (3) the KYN levels were higher in subjects with SCZ after antipsychotic treatments when compared with baseline. The evidence provides valuable insight of the potential underlying involvement of the KYN pathway in the pathogenesis of SCZ.

Effects of infliximab on brain neurochemistry of adults with bipolar depression.

OBJECTIVES: To explore the relationship between inflammation and neuronal metabolism in bipolar disorder (BD) by evaluating the neurochemical effects of the tumor necrosis factor-α (TNF-α) antagonist infliximab among individuals with bipolar depression METHODS: This is a post-hoc, exploratory analysis from a 12-week, randomized, double-blind, placebo-controlled trial with infliximab for adults with bipolar depression. We assessed the effects of infliximab on concentration of metabolites in the prefrontal cortex, using proton-magnetic resonance spectroscopy (1H-MRS), as well as its association with clinical outcomes (i.e. depressive symptom severity and cognitive function). RESULTS: Eighteen participants in the placebo and 15 in the infliximab group were included in this analysis. In the pre-specified primary outcome, there were no significant effects of treatment on prefrontal concentrations of N-acetylaspartate (NAA; p = 0.712). In the secondary analyses, there was a significant treatment by time interaction for glutamate (Glx; p = 0.018), indicating that Glx levels decreased in infliximab-treated patients, relative to placebo. Treatment group significantly moderated the association between changes in Glx levels and changes in a neurocognitive test (i.e. Digit Symbol Substitution Test; p = 0.014), indicating that in infliximab-treated participants reductions in Glx were associated with cognitive improvement. CONCLUSIONS: Treatment with infliximab did not affect prefrontal NAA concentration in adults with BD. Exploratory analysis suggested a potential effect of treatment on the glutamate system, a finding that should be confirmed and validated by additional studies.

Corrigendum to "Applications of machine learning algorithms to predict therapeutic outcomes in depression: A meta-analysis and systematic review." J Affect Disord. 241 (2018) 519-532.

The authors regret an error in one of the extracted data points in the meta-analysis. The classification accuracy for Serretti et al. (2007) was corrected to 64% (Table 3b). The overall results before and after this correction remain directionally consistent and are summarized below (Figures 2 and 3; Table 2; results subsection 3.6). The authors apologise for any inconvenience caused.

Leptin mediates improvements in cognitive function following treatment with infliximab in adults with bipolar depression.

A potential role for leptin in the pathophysiology of bipolar disorder (BD) has been proposed. We recently investigated the effects of the tumor necrosis factor-alpha (TNF-α) antagonist infliximab in individuals with bipolar depression. Leptin is known to interact with the TNF-α system. Herein, we aimed to explore infliximab's effects on leptin and its relationship with brain structure and function. Sixty adults with bipolar depression were enrolled in this randomized, double-blind, 12-week clinical trial of adjunctive infliximab (n = 29) and saline control (n = 31), which were administered intravenously at weeks 0, 2, and 6. Plasma concentrations of leptin, TNF-α and soluble TNF receptors (sTNFR) 1 and 2 were assessed at weeks 0, 2, 6, and 12. We observed a significant decrease in leptin levels in infliximab-treated patients, relative to placebo. Infliximab treatment also significantly reduced TNF-α and sTNFR2, but not sTNFR1 levels. Changes in sTNR2 levels at week 6 significantly determined changes in leptin at week 12 in infliximab-, but not placebo-treated participants. Improvements in verbal memory and increases in global cortical volume were associated with reduction in leptin levels in the treatment group. Mediation analysis indicated that cognitive improvement in infliximab-treated patients was mediated by reductions in leptin levels, which in its turn were determined by decreases in sTNR2 levels. In conclusion, infliximab treatment reduced plasma leptin levels in individuals with BD, through modulation of sTNFR2. Decreases in leptin signaling were associated with an increase in global cortical volume and better performance in a verbal memory task.

Efficacy of adjunctive infliximab vs. placebo in the treatment of anhedonia in bipolar I/II depression.

We investigated the efficacy of tumour necrosis factor (TNF)-α antagonist infliximab on a measure of anhedonia amongst individuals with bipolar I/II depression (ClinicalTrials.gov identifier NCT02363738). Adults (ages 18-65) with bipolar I/II disorder currently experiencing a major depressive episode with a higher probability of inflammatory activity (i.e., meeting one or more of the following inflammatory/metabolic criteria: obesity and dyslipidemia/hypertension, daily cigarette smoking, diabetes mellitus, migraine, inflammatory bowel disease, and/or C-reactive protein level of ⩾5 mg/L) were enrolled in a double-blind, 12-week clinical trial of adjunctive infliximab (5 mg/kg) and saline control, which were administered at weeks 0, 2, and 6. The primary outcome measure for the present secondary analysis was change in the Snaith-Hamilton Pleasure Scale (SHAPS) total score between placebo- and infliximab-treated subjects from baseline to weeks 6 and 12. Plasma concentrations of TNF-α and soluble TNF receptors (sTNFR) 1 and 2 were assessed at weeks 0, 2, 6, and 12. Sixty eligible adults received treatment with infliximab (n=29) or placebo (n=31); 47 subjects completed the study (infliximab: n=21, placebo: n=26). Overall, infliximab-randomized subjects exhibited significantly larger increases in SHAPS total score, denoting greater reductions in anhedonic symptoms, when compared to placebo-randomized subjects (treatment × time interaction effect: χ2=7.15,df=2,p=0.03). Anti-anhedonic efficacy was moderated by baseline plasma levels of TNF-α and sTNFR1, but not by changes in TNF-α or sTNFR1 concentrations. Baseline and changes in sTNFR2 concentrations did not moderate anti-anhedonic efficacy. Infliximab significantly improved a measure of anhedonia relative to placebo in adults with bipolar I/II depression at week 6; intervention efficacy was not sustained 6 weeks after the final infusion.

Metabolic profiling for water-soluble metabolites in patients with schizophrenia and healthy controls in a Chinese population: A case-control study.

Objectives: Objective measures integrated with clinical symptoms may improve early prevention and detection of schizophrenia. Herein we aim to evaluate potential water-soluble metabolic biomarkers in schizophrenia.Methods: We recruited adults with schizophrenia (n = 113) who had not received pharmacological treatment for at least 1 month prior to enrollment and 111 age- and sex-matched healthy subjects from Weifang, Shandong province, China. All serum samples were analysed using liquid chromatography-tandem mass spectrometry coupled with a hydrophilic interaction liquid chromatography column.Results: Eleven metabolites, namely carnitines (oleoylcarnitine, l-palmitoylcarnitine, 9-decenoylcarnitine and 2-trans,4-cis-decadienoylcarnitine), polar lipids (lysophosphatidylcholine (LPC)(P-16:0), LPC (16:0), LPC (15:0) and LPC(14:0)), amino acids (taurine and l-arginine), and organic acid (2,5-dichloro-4-oxohex-2-enedioate), separated the patients and healthy controls. Compared with healthy controls, taurine, l-palmitoylcarnitine and oleoylcarnitine levels were higher, whereas the remaining eight metabolites were lower in patients with schizophrenia. A combination of four metabolites, i.e., oleoylcarnitine, 9-decenoylcarnitine, LPC (15:0) and LPC (14:0), provided the most robust between-group separation.Conclusions: This study appears to distinguish between groups of patients and controls, which should be considered as a contribution to putative potential biomarkers. The water-soluble metabolites were determined to be significantly different between the groups in the current study, and were primarily related to cellular bioenergetics, notably oxidative stress.

Efficacy of Adjunctive Infliximab vs Placebo in the Treatment of Adults With Bipolar I/II Depression: A Randomized Clinical Trial.

Importance: To our knowledge, no study has previously evaluated whether individuals with bipolar depression enriched a priori on the basis of biochemical and/or phenotypic immuno-inflammatory activation would differentially respond to an anti-inflammatory agent for the treatment of depressive symptoms. Objective: To assess the antidepressant efficacy of adjunctive infliximab, a monoclonal antibody targeting tumor necrosis factor, in adults with bipolar I and bipolar II depression and inflammatory conditions. Design, Setting, and Participants: This 12-week, randomized, double-blind, placebo-controlled, parallel-group trial of 60 participants was conducted at 2 outpatient tertiary care sites in Canada and the United States. Eligible adults (aged 18-65 years) met DSM-5-defined criteria for bipolar I or bipolar II depression and exhibited pretreatment biochemical and/or phenotypic evidence of inflammatory activation. Participants were enrolled between October 1, 2015, and April 30, 2018. Data analysis was performed from May 1 through July 31, 2018, using modified intent-to-treat analysis. Interventions: Patients were randomized to receive 3 intravenous infusions of infliximab therapy or placebo at baseline and at weeks 2 and 6 of the 12-week study. Main Outcomes and Measures: The primary efficacy outcome was baseline-to-end point (ie, week-12) change in Montgomery-Asberg Depression Rating Scale (MADRS) total score. History of childhood maltreatment, as assessed by the Childhood Trauma Questionnaire, was used for exploratory analyses as 1 of several secondary outcomes. Results: A total of 60 participants were randomized to infliximab (n = 29 [48%]; mean [SD] age, 45.0 [11.7] years; 20 of 28 female [71%]) or to placebo (n = 31 [52%]; mean [SD] age, 46.8 [10.2] years; 26 of 30 female [87%]) across study sites. Overall baseline-to-end point change in MADRS total score was observed across treatment × time interaction (χ2 = 10.33; P = .04); reduction in symptom severity was not significant at week 12 (relative risk, 1.09; 95% CI, 0.80-1.50; df = 1; P = .60). As part of a secondary analysis, a significant treatment × time × childhood maltreatment interaction was observed in which infliximab-treated individuals with childhood history of physical abuse exhibited greater reductions in MADRS total score (χ2 = 12.20; P = .02) and higher response rates (≥50% reduction in MADRS total score) (χ2 = 4.05; P = .04). Conclusions and Relevance: Infliximab did not significantly reduce depressive symptoms compared with placebo in adults with bipolar depression. Results from secondary analyses identified a subpopulation (ie, those reporting physical and/or sexual abuse) that exhibited a significant reduction in depressive symptoms with infliximab treatment compared with placebo. Trial Registration: ClinicalTrials.gov identifier: NCT02363738.

The neural systems of emotion regulation and abnormalities in major depressive disorder.

Major depressive disorder (MDD) is a mental disorder characterized by aberrant emotion regulation. The capacity for emotion regulation stems from diverse neural circuits including higher level cognitive structures involved in processing contextual information, and lower level limbic structures involved in triggering emotional expression. Cognitive theories of depression posit that the MDD-specific abnormalities in emotional control derive itself from dysfunctional cognitive processes including biased attention, rumination, and altered information processing and memory. The main objectives of the current narrative review are to summarize the major neural systems involved in emotion regulation in humans, and to describe how these systems are dysregulated in MDD. The findings will be briefly discussed in the context of a conceptual framework of depression (i.e., Beck's cognitive model of depression), and neural targets of conventional treatments for depression will also be discussed. MDD exemplifies the critical importance of appropriate emotion regulation to human health and wellbeing, and demonstrates the personal and social impact of emotion dysregulation.

Stress, epigenetics and depression: A systematic review.

Environmental stressors, such as childhood maltreatment, have been recognized to contribute to the development of depression. Growing evidence suggests that epigenetic changes are a key mechanism by which stressors interact with the genome leading to stable changes in DNA structure, gene expression, and behaviour. The current review aimed to evaluate the relationship between stress-associated epigenetic changes and depression. Human studies were identified via systematic searching of PubMed/Medline from inception to February 2018. Seventeen articles were identified. Stress-associated epigenetic changes in the following genes were correlated with depression: NRC31, SLCA4, BDNF, FKBP5, SKA2, OXTR, LINGO3, POU3F1 and ITGB1. Epigenetic changes in glucocorticoid signaling (e.g., NR3C1, FKBP5), serotonergic signaling (e.g. SLC6A4), and neurotrophin (e.g., BDNF) genes appear to be the most promising therapeutic targets for future research. However, continued research is warranted due to inconsistent findings regarding the directionality of epigenetic modification. Future studies should also aim to control for the use of psychotropic agents due to their widespread use in depressed populations and established effects on DNA methylation.