Molecular characterization of depression trait and state

Effects of mind-body therapies on depression among adolescents: a systematic review and network meta-analysis

Background

Depression poses significant threats to adolescents' health globally. Research has shown the potential of mind-body therapies to alleviate depression, but limited studies have directly compared the therapeutic effects of different types of mind-body therapies on adolescent depression and the optimal therapy remain unclear. Therefore, we conducted a systematic review and network meta-analysis of randomized controlled trials that met the inclusion criteria to explore the effectiveness of different types of mind-body therapies as interventions to improve depression among adolescents, and to identify the most effective interventions.

Methods

A comprehensive search of databases including PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus up to January 2024 was conducted to assess the impact of mind-body therapies on depression among adolescents. The risk of bias of the included studies was evaluated using Cochrane Review Manager 5.4. STATA 18.0 was used for network meta-analysis. The node-splitting method was used to test the local inconsistency of the network meta-analysis. Funnel plots and the Egger's test were utilized to assess the potential impact of bias in this study.

Result

This network meta-analysis included 9 randomized controlled trials involving a total of 955 subjects. The results indicated that yoga, dance therapy and Tai Chi were more effective than other mind-body therapies in reducing symptoms of depression among adolescents. Specifically, according to the SUCRA ranking, yoga was rated to be the optimal intervention for adolescents with depression (SCURA: 82.2%), followed by dance therapy (SCURA: 77.5%) and Tai Chi (SCURA: 64.9%).

Conclusion

This study revealed that mind-body therapies have positive effects on improving depression among adolescents. Yoga may be the most effective intervention among the different types of mind-body therapies. However, due to the small sample size of patients included, the certainty of the results was limited to some extent. Therefore, further investigation is necessary to strengthen the evidence base when more relevant studies become available.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024508774.

Disentangling transcriptomic heterogeneity within the human subgenual anterior cingulate cortex

The subgenual anterior cingulate cortex (sgACC) is a critical site for understanding the neural correlates of affect and emotion. While the activity of the sgACC is functionally homogenous, it is comprised of multiple Brodmann Areas (BAs) that possess different cytoarchitectures. In some sgACC BAs, Layer 5 is sublaminated into L5a and L5b which has implications for its projection targets. To understand how the transcriptional profile differs between the BAs, layers, and sublayers of human sgACC, we collected layer strips using laser capture microdissection followed by RNA sequencing. We found no significant differences in transcript expression in these specific cortical layers between BAs within the sgACC. In contrast, we identified striking differences between Layers 3 and 5a or 5b that were concordant across sgACC BAs. We found that sublayers 5a and 5b were transcriptionally similar. Pathway analyses of L3 and L5 revealed overlapping biological processes related to synaptic function. However, L3 was enriched for pathways related to cell-to-cell junction and dendritic spines whereas L5 was enriched for pathways related to brain development and presynaptic function, indicating potential functional differences across layers. Our study provides important insight into normative transcriptional features of the sgACC.

Multiple cognition associated multimodal brain networks in major depressive disorder

Major depressive disorder frequently leads to cognitive impairments, significantly affecting patients' quality of life. However, the neurobiological mechanisms underlying cognitive deficits remain unclear. This study aimed to explore multimodal imaging biomarkers associated with cognitive function in major depressive disorder. Five cognitive scores (sustained attention, visual recognition memory, pattern recognition memory, executive function, and working memory) were used as references to guide the fusion of gray matter volume and amplitude of the low frequency fluctuation. Social function was assessed after 2 yr. Linear regression analysis was performed to identify brain features that were associated with social function of patients with major depressive disorder. Finally, we included 131 major depressive disorder and 145 healthy controls. A multimodal frontal-insula-occipital network associated with sustained attention was found to be associated with social functioning in major depressive disorders. Analysis across different cognitive domains revealed that gray matter volume exhibited greater sensitivity to differences, while amplitude of the low frequency fluctuation consistently decreased in the right temporal-occipital-hippocampus circuit. The consistent functional changes across the 5 cognitive domains were related to symptom severity. Overall, these findings provide insights into biomarkers associated with multiple cognitive domains in major depressive disorder. These results may contribute to the development of effective treatment targeting cognitive deficits and social function.

LPS-induced inflammation reduces GABAergic interneuron markers and brain-derived neurotrophic factor in mouse prefrontal cortex and hippocampus

Inflammation, reduced gamma-aminobutyric acidergic (GABAergic) function and altered neuroplasticity are co-occurring pathophysiologies in major depressive disorder (MDD). However, the link between these biological changes remains unclear. We hypothesized that inflammation induces deficits in GABAergic interneuron markers and that this effect is mediated by brain-derived neurotrophic factor (BDNF). We report here that systemic inflammation induced by intraperitoneal injection of lipopolysaccharide (LPS) (0.125, 0.25, 0.5, 1, 2 mg/kg) in the first cohort of C57BL/6 mice (n = 72; 10-11 weeks; 50% female) resulted in increased interleukin 1-beta and interleukin-6 in prefrontal cortex (PFC) and hippocampus (HPC), as measured using enzyme-linked immunosorbent assay (ELISA). Quantitative real-time polymerase reaction (qPCR) was used to explore the effect of LPS on the expression of GABAergic interneuron markers. In the PFC of the second cohort (n = 39; 10-11 weeks; 50% female), 2 mg/kg of LPS decreased the expression of somatostatin (Sst) (p = 0.0014), parvalbumin (Pv) (p = 0.0257), cortistatin (Cort) (p = 0.0003), neuropeptide Y (Npy) (p = 0.0033) and cholecystokinin (Cck) (p = 0.0041), and did not affect corticotropin-releasing hormone (Crh) and vasoactive intestinal peptide (Vip) expression. In the HPC, 2 mg/kg of LPS decreased the expression of Sst (p = 0.0543), Cort (p = 0.0011), Npy (p = 0.0001), and Cck (p < 0.0001), and did not affect Crh, Pv, and Vip expression. LPS decreased the expression of Bdnf in the PFC (p < 0.0001) and HPC (p = 0.0003), which significantly correlated with affected markers (Sst, Pv, Cort, Cck, and Npy). Collectively, these results suggest that inflammation may causally contribute to cortical cell microcircuit GABAergic deficits observed in MDD.

Enhancing the revelation of key genes and interaction networks in non-small cell lung cancer with major depressive disorder: A bioinformatics analysis

Background and Aims

Lung cancer is ranked as the second most prevalent form of cancer worldwide. Nonsmall cell lung cancer (NSCLC) represents the predominant histological subtype. Research suggests that one-third of lung cancer patients also experiencing depression. Antidepressants play an indispensable role in the management of NSCLC. Despite significant advancements in treatment, lung cancer patients still face a high mortality rate. Major depressive disorder (MDD) and related antidepressants involved in treatment efficacy and prognosis of NSCLC. However, there has been a lack of screening and analysis regarding genes and networks associated with both NSCLC and MDD.

Methods

To investigate the correlation between MDD and NSCLC, our discovery and validation analysis included four datasets from the Gene Expression Omnibus database from NSCLC or MDD. Differential gene expression (DEGs) analysis, GO and KEGG Pathway, and protein-protein interaction network analyzes to identify hub genes, networks, and associated observations link between MDD and NSCLC.

Results

The analysis of two datasets yielded a total of 84 downregulated and 52 upregulated DEGs. Pathway enrichment analyzes indicated that co-upregulated genes were enriched in the regulation of positive regulation of cellular development, collagen-containing extracellular matrix (ECM), cytokine binding, and axon guidance. We identified 20 key genes, which were further analyzed using the MCODE plugin to identify two core subnetworks. The integration of functionally similar genes provided valuable insights into the potential involvement of these hub genes in diverse biological processes including angiogenesis humoral immune response regulation inflammatory response organization ECM network.

Conclusion

We have identified a total of 136 DEGs that participate in multiple biological signaling pathways. A total of 20 hub genes have demonstrated robust associations, potentially indicating novel diagnostic and therapeutic targets for both diseases.

Differential Serum Levels of CACNA1C, Circadian Rhythm and Stress Response Molecules in Subjects with Bipolar Disorder: Associations with Genetic and Clinical Factors

Background

Many patients with bipolar disorder (BD) do not respond to or have difficulties tolerating lithium and/or other mood stabilizing agents. There is a need for personalized treatments based on biomarkers in guiding treatment options. The calcium voltage-gated channel CACNA1C is a promising candidate for developing personalized treatments. CACNA1C is implicated in BD by genome-wide association studies and several lines of evidence suggest that targeting L-type calcium channels could be an effective treatment strategy. However, before such individualized treatments can be pursued, biomarkers predicting treatment response need to be developed.

Methods

As a first step in testing the hypothesis that CACNA1C genotype is associated with serum levels of CACNA1C, we conducted ELISA measures on serum samples from 100 subjects with BD and 100 control subjects.

Results

We observed significantly higher CACNA1C (p<0.01) protein levels in subjects with BD. The risk SNP (rs11062170) showed functional significance as subjects homozygous for the risk allele (CC) had significantly greater CACNA1C protein levels compared to subjects with one (p=0.013) or no copies (p=0.009). We observed higher somatostatin (SST) (p<0.003) protein levels and lower levels of the clock protein ARTNL (p<0.03) and stress signaling factor corticotrophin releasing hormone (CRH) (p<0.001) in BD. SST and PER2 protein levels were associated with both alcohol dependence and lithium response.

Conclusions

Our findings represent the first evidence for increased serum levels of CACNA1C in BD. Along with altered levels of SST, ARNTL, and CRH our findings suggest CACNA1C is associated with circadian rhythm and stress response disturbances in BD.

The Ribosome Hypothesis: Decoding Mood Disorder Complexity

Several types of mood disorders lie along a continuum, with nebulous boundaries between them. Understanding the mechanisms that contribute to mood disorder complexity is critical for effective treatment. However, present treatments are largely centered around neurotransmission and receptor-based hypotheses, which, given the high instance of treatment resistance, fail to adequately explain the complexities of mood disorders. In this opinion piece, based on our recent results, we propose a ribosome hypothesis of mood disorders. We suggest that any hypothesis seeking to explain the diverse nature of mood disorders must incorporate infrastructure diversity that results in a wide range of effects. Ribosomes, with their mobility across neurites and complex composition, have the potential to become specialized during stress; thus, ribosome diversity and dysregulation are well suited to explaining mood disorder complexity. Here, we first establish a framework connecting ribosomes to the current state of knowledge associated with mood disorders. Then, we describe the potential mechanisms through which ribosomes could homeostatically regulate systems to manifest diverse mood disorder phenotypes and discuss approaches for substantiating the ribosome hypothesis. Investigating these mechanisms as therapeutic targets holds promise for transdiagnostic avenues targeting mood disorders.

[Targeting NMDAR/AMPAR: a promising pharmacotherapeutic approach for depressive disorders]

Depression is a leading cause of disability and reduced work capacity worldwide. The monoamine theory of the pathogenesis of depression has remained dominant for many decades, however, drugs developed on its basis have limited efficacy. Exploring alternative mechanisms underlying this pathology could illuminate new avenues for pharmacological intervention. Targeting glutamatergic pathways in the CNS, particularly through modulation of NMDA and AMPA receptors, demonstrates promising results. This review presents some existing drugs with glutamatergic activity and novel developments based on it to enhance the efficacy of pharmacotherapy for depressive disorders.

Transcriptional dissection of symptomatic profiles across the brain of men and women with depression

Major depressive disorder (MDD) is one of the most important causes of disability worldwide. While recent work provides insights into the molecular alterations in the brain of patients with MDD, whether these molecular signatures can be associated with the expression of specific symptom domains remains unclear. Here, we identified sex-specific gene modules associated with the expression of MDD, combining differential gene expression and co-expression network analyses in six cortical and subcortical brain regions. Our results show varying levels of network homology between males and females across brain regions, although the associations between these structures and the expression of MDD remain highly sex specific. We refined these associations to several symptom domains and identified transcriptional signatures associated with distinct functional pathways, including GABAergic and glutamatergic neurotransmission, metabolic processes and intracellular signal transduction, across brain regions associated with distinct symptomatic profiles in a sex-specific fashion. In most cases, these associations were specific to males or to females with MDD, although a subset of gene modules associated with common symptomatic features in both sexes were also identified. Together, our findings suggest that the expression of distinct MDD symptom domains associates with sex-specific transcriptional structures across brain regions.

Ribosomal dysregulation: A conserved pathophysiological mechanism in human depression and mouse chronic stress

The underlying biological mechanisms that contribute to the heterogeneity of major depressive disorder (MDD) presentation remain poorly understood, highlighting the need for a conceptual framework that can explain this variability and bridge the gap between animal models and clinical endpoints. Here, we hypothesize that comparative analysis of molecular data from different experimental systems of chronic stress, and MDD has the potential to provide insight into these mechanisms and address this gap. Thus, we compared transcriptomic profiles of brain tissue from postmortem MDD subjects and from mice exposed to chronic variable stress (CVS) to identify orthologous genes. Ribosomal protein genes (RPGs) were down-regulated, and associated ribosomal protein (RP) pseudogenes were up-regulated in both conditions. A seeded gene co-expression analysis using altered RPGs common between the MDD and CVS groups revealed that down-regulated RPGs homeostatically regulated the synaptic changes in both groups through a RP-pseudogene-driven mechanism. In vitro analysis demonstrated that the RPG dysregulation was a glucocorticoid-driven endocrine response to stress. In silico analysis further demonstrated that the dysregulation was reversed during remission from MDD and selectively responded to ketamine but not to imipramine. This study provides the first evidence that ribosomal dysregulation during stress is a conserved phenotype in human MDD and chronic stress-exposed mouse. Our results establish a foundation for the hypothesis that stress-induced alterations in RPGs and, consequently, ribosomes contribute to the synaptic dysregulation underlying MDD and chronic stress-related mood disorders. We discuss the role of ribosomal heterogeneity in the variable presentations of depression and other mood disorders.

Transcriptional dissection of symptomatic profiles across the brain of men and women with depression

Major depressive disorder (MDD) is one of the most important causes of disability worldwide. While recent work provides insights into the molecular alterations in the brain of patients with MDD, whether these molecular signatures can be associated with the expression of specific symptom domains in males and females remains unclear. Here, we identified sex-specific gene modules associated with the expression of MDD, combining differential gene expression and co-expression network analyses in six cortical and subcortical brain regions. Our results show varying levels of network homology between males and females across brain regions, although the association between these structures and the expression of MDD remains highly sex-specific. We refined these associations to several symptom domains and identified transcriptional signatures associated with distinct functional pathways, including GABAergic and glutamatergic neurotransmission, metabolic processes, and intracellular signal transduction, across brain regions associated with distinct symptomatic profiles in a sex-specific fashion. In most cases, these associations were specific to males or to females with MDD, although a subset of gene modules associated with common symptomatic features in both sexes was also identified. Together, our findings suggest that the expression of distinct MDD symptom domains is associated with sex-specific transcriptional structures across brain regions.

Effectiveness of yoga for major depressive disorder: A systematic review and meta-analysis

Objective

Major depressive disorder (MDD) has a relapse rate that cannot be ignored and places a tremendous burden on the patient in the prevention and treatment process. Yoga, a combination of physical and mental exercises, is effective and acceptable for the adjunctive treatment of MDD. This study aimed to explore further the evidence of yoga's efficacy for patients with MDD.

Methods

PubMed, Embase, Cochrane library, PsycINFO, SinoMed, CNKI, Wanfang, and VIP databases from their inception to 13 October 2022 were searched by a pre-defined search strategy. RCTs of patients with MDD who met diagnostic criteria for yoga treatment were included. RoB2.0 was used to evaluate the quality of the literature. Improvement in depressive symptoms was assessed by the Beck Depression Inventory (BDI), Hamilton Depression Rating Scale (HAMD), or other scales were used as primary outcome indicators, and improvement in anxiety was assessed by the Hamilton Anxiety Scale (HAMA) and State-Trait Anxiety Inventory (STAI) scale as secondary outcome indicators. RR and Cohen's d at 95% CI were used as effect size estimates, and Q and I2 were used to evaluate the size of heterogeneity, with a p-value less than 0.05 indicating statistical significance.

Results

Thirty-four RCT studies, including 1,269 patients in the treatment group and 1,072 patients in the control group, 48.4% of whom were women, were included in the study. Compared to the control group, the BDI-II results yielded a moderate effect of yoga on the improvement of depressive symptoms (Cohen's d = -0.60; 95% CI: -1.00 to -0.21; p < 0.01), the HAMD results yielded a moderate improvement of yoga on the severity of depressive symptoms (Cohen's d = -0.64; 95% CI: -0.98 to -0.30; p < 0.01), and the STAI results can be concluded that yoga had a negligible effect on the improvement of the level of anxiety (Cohen's d = -0.26; 95% CI: -0.48 to -0.04; p = 0.02). No adverse events occurred in the yoga group during the treatment.

Conclusion

Yoga can improve depressive symptoms and anxiety in patients with MDD and has a safe and wide patient acceptance.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [PROSPERO, CRD42022373282].

Acupuncture treatment for post-stroke depression: Intestinal microbiota and its role

Stroke-induced depression is a common complication and an important risk factor for disability. Besides psychiatric symptoms, depressed patients may also exhibit a variety of gastrointestinal symptoms, and even take gastrointestinal symptoms as the primary reason for medical treatment. It is well documented that stress may disrupt the balance of the gut microbiome in patients suffering from post-stroke depression (PSD), and that disruption of the gut microbiome is closely related to the severity of the condition in depressed patients. Therefore, maintaining the balance of intestinal microbiota can be the focus of research on the mechanism of acupuncture in the treatment of PSD. Furthermore, stroke can be effectively treated with acupuncture at all stages and it may act as a special microecological regulator by regulating intestinal microbiota as well. In this article, we reviewed the studies on changing intestinal microbiota after acupuncture treatment and examined the existing problems and development prospects of acupuncture, microbiome, and poststroke depression, in order to provide new ideas for future acupuncture research.

Pain intensity and psychological distress show different associations with interference and lack of life control: A clinical registry-based cohort study of >40,000 chronic pain patients from SQRP

Background

Both chronic pain and depressive and/or anxiety symptoms are associated with negative impacts on daily living, including interference and lack of life control. However, little is known about how pain and psychological distress affect these impacts.

Aim

The first aim was to assess how pain intensity, psychological distress, and social support interact with interference and lack of life control. A second aim was to investigate whether the strength of these relationships is moderated by the presence or absence of depression and/or anxiety.

Subjects and methods

Patient-Reported Outcome Measures (PROMs), which are available in the Swedish Quality Registry for Pain Rehabilitation (SQRP), were retrieved for patients with chronic pain (N = 40,184). A theoretical model with the constructs/latent variables pain intensity, psychological distress, interference, lack of life control, and social support was proposed and analyzed using Partial Least Squares Structural Equation Modelling (PLS-SEM). Indicators for these constructs were identified from the PROMs of the SQRP. Two models of the total cohort, which differed with respect to the causal relationship between pain intensity and psychological distress, were investigated. The moderating effects of anxiety and/or depression were also analyzed.

Results

Relatively low correlation and explanatory power (R ²= 0.16) were found for the pain intensity-psychological distress relationship. Pain intensity had a stronger effect on interference than on lack of life control. The reverse was found for psychological distress - i.e., psychological distress seemed to have a higher negative influence on function than on interference. The underlying assumption of the causal relationship between pain intensity and psychological distress determined how strong pain intensity and psychological distress influenced interference and lack of life control. Social support showed very similar absolute significant correlations with interference and lack of life control. Interference and lack of life control showed relatively weak associations. The psychological distress level was a moderating factor for several of the paths investigated.

Discussion and conclusion

A clinical treatment consequence of the low correlation between pain intensity and psychological distress may be that clinically treating one may not reduce the effect of the other. The relative importance of pain intensity and psychological distress on interference and lack of life control depends on the underlying assumption concerning the pain intensity-psychological distress relationship. Interference and lack of life control showed relatively weak associations, underscoring the need to clinically assess them separately. Social support influenced both impact constructs investigated. The cohort display heterogeneity and thus presence of definite signs of anxiety and/or depression or not was a moderating factor for several of the associations (paths) investigated. The results are important both for the assessments and the design of treatments for patients with chronic pain.

Antipsychotics impair regulation of glucose metabolism by central glucose

Hypothalamic detection of elevated circulating glucose triggers suppression of endogenous glucose production (EGP) to maintain glucose homeostasis. Antipsychotics alleviate symptoms associated with schizophrenia but also increase the risk for impaired glucose metabolism. In the current study, we examined whether two acutely administered antipsychotics from different drug classes, haloperidol (first generation antipsychotic) and olanzapine (second generation antipsychotic), affect the ability of intracerebroventricular (ICV) glucose infusion approximating postprandial levels to suppress EGP. The experimental protocol consisted of a pancreatic euglycemic clamp, followed by kinomic and RNA-seq analyses of hypothalamic samples to determine changes in serine/threonine kinase activity and gene expression, respectively. Both antipsychotics inhibited ICV glucose-mediated increases in glucose infusion rate during the clamp, a measure of whole-body glucose metabolism. Similarly, olanzapine and haloperidol blocked central glucose-induced suppression of EGP. ICV glucose stimulated the vascular endothelial growth factor (VEGF) pathway, phosphatidylinositol 3-kinase (PI3K) pathway, and kinases capable of activating K_ATP channels in the hypothalamus. These effects were inhibited by both antipsychotics. In conclusion, olanzapine and haloperidol impair central glucose sensing. Although results of hypothalamic analyses in our study do not prove causality, they are novel and provide the basis for a multitude of future studies.

Activation of Somatostatin-Expressing Neurons in the Lateral Septum Improves Stress-Induced Depressive-like Behaviors in Mice

Depression is a debilitating mood disorder with highly heterogeneous pathogenesis. The limbic system is well-linked to depression. As an important node in the limbic system, the lateral septum (LS) can modulate multiple affective and motivational behaviors. However, the role of LS in depression remains unclear. By using c-Fos expression mapping, we first screened and showed activation of the LS in various depression-related behavioral tests, including the forced swim test (FST), tail suspension test (TST), and sucrose preference test. In the LS, more than 10% of the activated neurons were somatostatin-expressing (SST) neurons. We next developed a microendoscopic calcium imaging method in freely moving mice and revealed that LS^SST neural activity increased during mobility in the TST but not open field test. We hypothesize that LS^SST neuronal activity is linked to stress and depression. In two mouse models of depression, repeated lipopolysaccharide (LPS) injection and chronic restraint stress (CRS), we showed that LS neuronal activation was suppressed. To examine whether the re-activation of LS^SST neurons can be therapeutically beneficial, we optogenetically activated LS^SST neurons and produced antidepressant-like effects in LPS-injected mice by increasing TST motility. Moreover, chemogenetic activation of LS^SST neurons increased FST struggling in the CRS-exposed mice. Together, these results provide the first evidence of a role for LS^SST neurons in regulating depressive-like behaviors in mice and identify them as a potential therapeutic target for neuromodulation-based intervention in depression.

Differential vulnerability of anterior cingulate cortex cell types to diseases and drugs

In psychiatric disorders, mismatches between disease states and therapeutic strategies are highly pronounced, largely because of unanswered questions regarding specific vulnerabilities of different cell types and therapeutic responses. Which cellular events (housekeeping or salient) are most affected? Which cell types succumb first to challenges, and which exhibit the strongest response to drugs? Are these events coordinated between cell types? How does disease and drug effect this coordination? To address these questions, we analyzed single-nucleus-RNAseq (sn-RNAseq) data from the human anterior cingulate cortex-a region involved in many psychiatric disorders. Density index, a metric for quantifying similarities and dissimilarities across functional profiles, was employed to identify common or salient functional themes across cell types. Cell-specific signatures were integrated with existing disease and drug-specific signatures to determine cell-type-specific vulnerabilities, druggabilities, and responsiveness. Clustering of functional profiles revealed cell types jointly participating in these events. SST and VIP interneurons were found to be most vulnerable, whereas pyramidal neurons were least. Overall, the disease state is superficial layer-centric, influences cell-specific salient themes, strongly impacts disinhibitory neurons, and influences astrocyte interaction with a subset of deep-layer pyramidal neurons. In absence of disease, drugs profiles largely recapitulate disease profiles, offering a possible explanation for drug side effects. However, in presence of disease, drug activities, are deep layer-centric and involve activating a distinct subset of deep-layer pyramidal neurons to circumvent the disease state's disinhibitory circuit malfunction. These findings demonstrate a novel application of sn-RNAseq data to explain drug and disease action at a systems level.

Single-cell transcriptome study in forensic medicine: prospective applications

Next-generation sequencing and single-cell RNA sequencing (scRNA-seq) technologies have advanced rapidly in recent years. scRNA-seq reveals the unique gene expression of each cell type, providing directions for exploring cell heterogeneity, cell type-specific responses to injury/disease, and the mechanisms underlying these processes. The development of sequencing technology and improved sequencing throughput have brought about a revolution in single-cell transcriptome study, bringing great benefits to the fields of medicine and biomedical science. From our perspective, certain issues in forensic medicine may potentially be addressed using single-cell transcriptome studies; however, this powerful technique has not yet attracted sufficient attention in forensic medicine-associated research. Therefore, examining and reviewing the latest developments and applications of single-cell transcriptome studies, we present our views on the future directions of forensic research using this technology, aiming to expand the frontiers of forensic science.

Sex-Specific Brain Transcriptional Signatures in Human MDD and Their Correlates in Mouse Models of Depression

Major depressive disorder (MDD) is amongst the most devastating psychiatric conditions affecting several millions of people worldwide every year. Despite the importance of this disease and its impact on modern societies, still very little is known about the etiological mechanisms. Treatment strategies have stagnated over the last decades and very little progress has been made to improve the efficiency of current therapeutic approaches. In order to better understand the disease, it is necessary for researchers to use appropriate animal models that reproduce specific aspects of the complex clinical manifestations at the behavioral and molecular levels. Here, we review the current literature describing the use of mouse models to reproduce specific aspects of MDD and anxiety in males and females. We first describe some of the most commonly used mouse models and their capacity to display unique but also shared features relevant to MDD. We then transition toward an integral description, combined with genome-wide transcriptional strategies. The use of these models reveals crucial insights into the molecular programs underlying the expression of stress susceptibility and resilience in a sex-specific fashion. These studies performed on human and mouse tissues establish correlates into the mechanisms mediating the impact of stress and the extent to which different mouse models of chronic stress recapitulate the molecular changes observed in depressed humans. The focus of this review is specifically to highlight the sex differences revealed from different stress paradigms and transcriptional analyses both in human and animal models.

Lower Levels of GABAergic Function Markers in Corticotropin-Releasing Hormone-Expressing Neurons in the sgACC of Human Subjects With Depression

RATIONALE

A previous transcriptome meta-analysis revealed significantly lower levels of corticotropin-releasing hormone (CRH) mRNA in corticolimbic brain regions in major depressive disorder (MDD) subjects, suggesting that cortical CRH-expressing (CRH+) cells are affected in MDD. Rodent studies show that cortical CRH is mostly expressed in GABAergic interneurons; however, the characteristic features of CRH+ cells in human brain cortex and their association with MDD are largely unknown.

METHODS

Subgenual anterior cingulate cortex (sgACC) of human subjects without brain disorders were labeled using fluorescent in situ hybridization (FISH) for CRH and markers of excitatory (SLC17A7), inhibitory (GAD1) neurons, as well as markers of other interneuron subpopulations (PVALB, SST, VIP). MDD-associated changes in CRH+ cell density and cellular CRH expression (n = 6/group) were analyzed. RNA-sequencing was performed on sgACC CRH+ interneurons from comparison and MDD subjects (n = 6/group), and analyzed for group differences. The effect of reduced BDNF on CRH expression was tested in mice with blocked TrkB function.

RESULTS

About 80% of CRH+ cells were GABAergic and 17.5% were glutamatergic. CRH+ GABAergic interneurons co-expressed VIP (52%), SST (7%), or PVALB (7%). MDD subjects displayed lower CRH mRNA levels in GABAergic interneurons relative to comparison subjects without changes in cell density. CRH+ interneurons show transcriptomic profile suggesting lower excitability and less GABA release and reuptake. Further analyses suggested that these molecular changes are not mediated by altered glucocorticoid feedback and potentially occur downstream for a common modulator of neurotrophic function.

SUMMARY

CRH+ cells in human sgACC are a heterogeneous population of GABAergic interneurons, although largely co-expressing VIP. Our data suggest that MDD is associated with reduced markers of inhibitory function in sgACC CRH+ interneurons, and provide further evidence for impaired GABAergic function in the cortex in MDD.

Strategies to identify candidate repurposable drugs: COVID-19 treatment as a case example

Drug repurposing is an invaluable strategy to identify new uses for existing drug therapies that overcome many of the time and financial costs associated with novel drug development. The COVID-19 pandemic has driven an unprecedented surge in the development and use of bioinformatic tools to identify candidate repurposable drugs. Using COVID-19 as a case study, we discuss examples of machine-learning and signature-based approaches that have been adapted to rapidly identify candidate drugs. The Library of Integrated Network-based Signatures (LINCS) and Connectivity Map (CMap) are commonly used repositories and have the advantage of being amenable to use by scientists with limited bioinformatic training. Next, we discuss how these recent advances in bioinformatic drug repurposing approaches might be adapted to identify repurposable drugs for CNS disorders. As the development of novel therapies that successfully target the cause of neuropsychiatric and neurological disorders has stalled, there is a pressing need for innovative strategies to treat these complex brain disorders. Bioinformatic approaches to identify repurposable drugs provide an exciting avenue of research that offer promise for improved treatments for CNS disorders.