Potential of Circulating miRNAs as Molecular Markers in Mood Disorders and Associated Suicidal Behavior

Identification of mitophagy-related genes and analysis of immune infiltration in the astrocytes based on machine learning in the pathogenesis of major depressive disorder

BACKGROUNDS

Major depressive disorder (MDD) is a pervasive mental and mood disorder with complicated and heterogeneous etiology. Mitophagy, a selective autophagy of cells, specifically eliminates dysfunctional mitochondria. The mitochondria dysfunction in the astrocytes is regarded as a critical pathogenetic mechanism of MDD. However, studies on the mitophagy of astrocytes in MDD are scarce. To explore the impact of mitophagy on the astrocytes, we used bioinformatic methods to analyze the correlation between astrocyte-related genes and mitophagy-related genes in MDD.

METHODS

The microarray dataset of MDD was downloaded from the Gene Expression Omnibus database and identified astrocyte- and mitophagy-related differentially expressed genes (AMRDEGs). We used three machine learning algorithms to identify hub AMRDEGs and constructed a diagnostic prediction model. Also, we analyzed transcription factor-gene and gene-microRNA interaction networks, and the immune infiltration in MDD and healthy controls. Besides, we performed consensus clustering analysis, immune infiltration analysis, and gene set variation analysis of MDD samples.

RESULTS

The present research identified 3 hub AMRDEGs (GRN, NDUFAF4, and SNCA), and a good diagnostic model with potential clinical applications was constructed and validated. Besides, we identified 6 transcription factors and 14 microRNAs. The immune infiltration analysis showed that MDD was closely related to immune cells. Gene set variant analysis showed that MDD was related to immune and mitochondrial metabolism and inflammatory signaling pathways.

CONCLUSIONS

We identified 3 hub AMRDEGs, new biomarkers for treating and diagnosing MDD and associated with immuno-inflammation. Our research provides new insights into the early diagnosis and treatment of MDD.

Genetic-epigenetic-neuropeptide associations in mood and anxiety disorders: Toward personalized medicine

Mood and anxiety disorders are complex psychiatric conditions shaped by the multifactorial interplay of genetic, epigenetic, and neuropeptide factors. This review aims to elucidate the intricate interactions among these factors and their potential in advancing personalized medicine. We examine the genetic underpinnings, emphasizing key heritability studies and specific gene associations. The role of epigenetics is discussed, focusing on how environmental factors can modify gene expression and contribute to these disorders. Neuropeptides, including substance P, CRF, AVP, NPY, galanin, and kisspeptin, are evaluated for their involvement in mood regulation and their potential as therapeutic targets. Additionally, we address the emerging role of the gut microbiome in modulating neuropeptide activity and its connection to mood disorders. This review integrates findings from genetic, epigenetic, and neuropeptide research, offering a comprehensive overview of their collective impact on mood and anxiety disorders. By highlighting novel insights and potential clinical applications, we underscore the importance of a multi-omics approach in developing personalized treatment strategies. Future research directions are proposed to address existing knowledge gaps and translate these findings into clinical practice. Our review provides a fresh perspective on the pathophysiology of mood and anxiety disorders, paving the way for more effective and individualized therapies.

Deciphering and Targeting the ESR2-miR-10a-5p-BDNF Axis in the Prefrontal Cortex: Advancing Postpartum Depression Understanding and Therapeutics

Postpartum depression (PPD) represents a important emotional disorder emerging after childbirth, characterized by its complex etiology and challenging management. Despite extensive preclinical and clinical investigations underscoring the role of estrogen fluctuations and estrogen receptor genes in PPD, the precise mechanisms underpinning this condition have remained elusive. In our present study, animal behavioral studies have elucidated a tight link between the aberrant expression of ESR2, miR-10a-5p, and BDNF in the prefrontal cortex of mice exhibiting postpartum depressive-like behavior, shedding light on the potential molecular pathways involved. Integrating bioinformatics, in vivo, and cell transfection methodologies has unraveled the intricate molecular interplay between ESR2, miR-10a-5p, and BDNF. We identified ESR2 as a negative transcription factor that down-regulates miR-10a transcription, while miR-10a-5p serves as a negative regulator that suppresses BDNF expression. This molecular triad contributes to the pathogenesis of PPD by affecting synaptic plasticity, as evidenced by alterations in synapse-related proteins (e.g., SYP, SYN, and PSD95) and glutamate receptor expression. Additionally, primary neuron culture studies have confirmed the critical roles of ESR2 and miR-10a-5p in maintaining neuronal growth and morphology. Therapeutic interventions, including stereotactic and intranasal administration of antagomir or BDNF, have demonstrated significant potential in treating PPD, highlighting the therapeutic implications of targeting the negative transcriptional and regulatory interactions between ESR2, miR-10a-5p, and BDNF. Our findings endorse the hypothesis that estrogen fluctuations and estrogen receptor gene activity are pivotal stressors and risk factors for PPD, affecting central nervous system functionality and precipitating depressive behaviors postpartum.

MicroRNA-specific targets for neuronal plasticity, neurotransmitters, neurotrophic factors, and gut microbes in the pathogenesis and therapeutics of depression

Depression is of great concern because of the huge burden, and it is impacted by various epigenetic modifications, e.g., histone modification, covalent modifications in DNA, and silencing mechanisms of non-coding protein genes, e.g., microRNAs (miRNAs). MiRNAs are a class of endogenous non-coding RNAs. Alternations in specific miRNAs have been observed both in depressive patients and experimental animals. Also, miRNAs are highly expressed in the central nervous system and can be delivered to different tissues via tissue-specific exosomes. However, the mechanism of miRNAs' involvement in the pathological process of depression is not well understood. Therefore, we summarized and discussed the role of miRNAs in depression. Conclusively, miRNAs are involved in the pathology of depression by causing structural and functional changes in synapses, mediating neuronal regeneration, differentiation, and apoptosis, regulating the gut microbes and the expression of various neurotransmitters and BDNF, and mediating inflammatory and immune responses. Moreover, miRNAs can predict the efficacy of antidepressant medications and explain the mechanism of action of antidepressant drugs and aerobic exercise to prevent and assist in treating depression.

Up-regulation of HOXA-AS2 and MEG3 long non-coding RNAs acts as a potential peripheral biomarker for bipolar disorder

Bipolar disorder (BD) is a psychiatric condition that is frequently misdiagnosed and linked to inadequate treatment. Long non-coding RNAs (lncRNAs) have lately gained recognition as crucial genetic elements and are now regarded as regulatory mechanisms in the neurological system. Our objective was to measure the quantities of HOXA-AS2 and MEG3 ncRNA transcripts. HOXA-AS2 and MEG3 ncRNA levels were checked in the peripheral blood of 50 type I BD and 50 control samples by real-time PCR. Furthermore, we conducted ROC curve analysis and correlation analysis to examine the association between gene expression and specific clinical characteristics in instances with BD. Additionally, a computational study was performed to investigate the binding sites of miRNAs on the HOXA-AS2 and MEG3 lncRNAs. BD subjects showed a significant increase in the expression of HOXA-AS2 and MEG3 compared to controls. The lncRNAs HOXA-AS2 and MEG3 have an area under the ROC curve (AUC) values of 0.70 and 0.71, respectively. There was a significant correlation between the expression levels of ncRNAs HOXA-AS2 and MEG3 in the peripheral blood of patients with BD and occupation scores. The data presented indicate a potential correlation between the expression of HOXA-AS2 and MEG3 lncRNAs with an elevated risk of BD. Furthermore, these lncRNAs may be linked to several molecular pathways. Our findings indicate that the amounts of lncRNAs HOXA-AS2 and MEG3 in transcripts might be a promising potential biomarker for patients with BD.

Pediatric suicide: Review of a preventable tragedy

Concepts of suicide are explored in this issue with a focus on suicide in children and adolescents. The epidemiology of pediatric suicide in the United States is reviewed; also, risk and protective factors, as well as prevention strategies, are discussed. Suicide in the pediatric athlete and the potential protective effect of exercise are examined. In addition, this analysis addresses the beneficial role of psychological management as well as current research on pharmacologic treatment and brain stimulation procedures as part of comprehensive pediatric suicide prevention. Though death by suicide in pediatric persons has been and remains a tragic phenomenon, there is much that clinicians, other healthcare professionals, and society itself can accomplish in the prevention of pediatric suicide as well as the management of suicidality in our children and adolescents.

Deciphering Depression: Epigenetic Mechanisms and Treatment Strategies

Depression, a significant mental health disorder, is under intense research scrutiny to uncover its molecular foundations. Epigenetics, which focuses on controlling gene expression without altering DNA sequences, offers promising avenues for innovative treatment. This review explores the pivotal role of epigenetics in depression, emphasizing two key aspects: (I) identifying epigenetic targets for new antidepressants and (II) using personalized medicine based on distinct epigenetic profiles, highlighting potential epigenetic focal points such as DNA methylation, histone structure alterations, and non-coding RNA molecules such as miRNAs. Variations in DNA methylation in individuals with depression provide opportunities to target genes that are associated with neuroplasticity and synaptic activity. Aberrant histone acetylation may indicate that antidepressant strategies involve enzyme modifications. Modulating miRNA levels can reshape depression-linked gene expression. The second section discusses personalized medicine based on epigenetic profiles. Analyzing these patterns could identify biomarkers associated with treatment response and susceptibility to depression, facilitating tailored treatments and proactive mental health care. Addressing ethical concerns regarding epigenetic information, such as privacy and stigmatization, is crucial in understanding the biological basis of depression. Therefore, researchers must consider these issues when examining the role of epigenetics in mental health disorders. The importance of epigenetics in depression is a critical aspect of modern medical research. These findings hold great potential for novel antidepressant medications and personalized treatments, which would significantly improve patient outcomes, and transform psychiatry. As research progresses, it is expected to uncover more complex aspects of epigenetic processes associated with depression, enhance our comprehension, and increase the effectiveness of therapies.

A Decade of Dedication: Pioneering Perspectives on Neurological Diseases and Mental Illnesses

Welcome to Biomedicines' 10th Anniversary Special Issue, a journey through the human mind's labyrinth and complex neurological pathways [...].

Clinical Insights into MicroRNAs in Depression: Bridging Molecular Discoveries and Therapeutic Potential

Depression is a major contributor to the overall global burden of disease. The discovery of biomarkers for diagnosis or prediction of treatment responses and as therapeutic agents is a current priority. Previous studies have demonstrated the importance of short RNA molecules in the etiology of depression. The most extensively researched of these are microRNAs, a major component of cellular gene regulation and function. MicroRNAs function in a temporal and tissue-specific manner to regulate and modify the post-transcriptional expression of target mRNAs. They can also be shuttled as cargo of extracellular vesicles between the brain and the blood, thus informing about relevant mechanisms in the CNS through the periphery. In fact, studies have already shown that microRNAs identified peripherally are dysregulated in the pathological phenotypes seen in depression. Our article aims to review the existing evidence on microRNA dysregulation in depression and to summarize and evaluate the growing body of evidence for the use of microRNAs as a target for diagnostics and RNA-based therapies.

Finding biomarkers of experience in animals

At a time when there is a growing public interest in animal welfare, it is critical to have objective means to assess the way that an animal experiences a situation. Objectivity is critical to ensure appropriate animal welfare outcomes. Existing behavioural, physiological, and neurobiological indicators that are used to assess animal welfare can verify the absence of extremely negative outcomes. But welfare is more than an absence of negative outcomes and an appropriate indicator should reflect the full spectrum of experience of an animal, from negative to positive. In this review, we draw from the knowledge of human biomedical science to propose a list of candidate biological markers (biomarkers) that should reflect the experiential state of non-human animals. The proposed biomarkers can be classified on their main function as endocrine, oxidative stress, non-coding molecular, and thermobiological markers. We also discuss practical challenges that must be addressed before any of these biomarkers can become useful to assess the experience of an animal in real-life.

Validation of a youth suicide risk calculator in an adult sample with bipolar disorder

BACKGROUND

Bipolar disorder (BD) conveys the highest risk of suicide of all mental disorders. We sought to externally validate a risk calculator (RC) of suicide attempts developed in youth with BD from the Course and Outcome of Bipolar Youth (COBY) study in an adult sample.

METHODS

A prospective cohort of adults with BD from the National Institute of Mental Health Collaborative Depression Study (CDS; N = 427; mean (+/- SD) age at intake (36 +/- 13 years)) was secondarily analyzed to validate the COBY RC for one-year risk of suicide attempts/deaths. Nine of the ten predictor variables from the COBY RC were available in the CDS and used: age, age of mood disorder onset, first and second (partial) degree family history of suicide, history of psychotic symptoms, substance use disorder, prior suicide attempt, socioeconomic status, and non-suicidal self-injury (prospectively, incompletely at baseline).

RESULTS

Over a mean (SD) follow-up of 19 (10) years, 29 % of the CDS sample attempted suicide. The RC predicted suicide attempts/deaths over one-year follow-up with an area under the receiver operating characteristic curve (AUC) of 0.78 (95 % CI 0.75-0.80). The RC performed slightly better in those with a younger age of mood disorder onset.

LIMITATIONS

Clinical samples may limit generalizability; the RC does not assess more acute suicide risk.

CONCLUSIONS

One-year risk of suicide attempts/deaths can be predicted with acceptable accuracy in youth and adults with BD, comparable to commonly used RCs to predict cardiovascular risk. This RC may help identify higher-risk individuals with BD for personalized treatment and research. https://cobysuicideattemptsrc.shinyapps.io/Shiny.

MiR-10a, miR-15a, let-7a, and let-7g expression as stress-relevant biomarkers to assess acute or chronic psychological stress and mental health in human capillary blood

BACKGROUND

Psychological stress, as an important cofactor in the development of many acute and chronic diseases, is crucial for general health or well-being, and improved markers are needed to distinguish situations of progressive pathological development, such as depression, anxiety, or burnout, to be recognized at an early stage. Epigenetic biomarkers play an important role in the early detection and treatment of complex diseases such as cancer, and metabolic or mental disorders. Therefore, this study aimed to identify so-called miRNAs, which would be suitable as stress-related biomarkers.

METHODS AND RESULTS

In this study, 173 participants (36.4% males, and 63.6% females) were interviewed about stress, stress-related diseases, lifestyle, and diet to assess their acute and chronic psychological stress status. Using qPCR analysis, 13 different miRNAs (miR-10a-5p, miR-15a-5p, miR-16-5p, miR-19b-3p, miR-26b-5p, miR-29c-3p, miR-106b-5p, miR-126-3p, miR-142-3p, let-7a-5p, let-7g-5p, miR-21-5p, and miR-877-5p) were analyzed in dried capillary blood samples. Four miRNAs were identified, miR-10a-5p, miR-15a-5p, let-7a-5p, and let-7g-5p (p < 0.05), which could be used as possible candidates for measuring pathological forms of acute or chronic stress. Let-7a-5p, let-7g-5p, and miR-15a-5p (p < 0.05) were also significantly higher in subjects with at least one stress-related disease. Further, correlations were identified between let-7a-5p and meat consumption (p < 0.05) and between miR-15a-5p and coffee consumption (p < 0.05).

CONCLUSION

The examination of these four miRNAs as biomarkers using a minimally invasive method offers the possibility of detecting health problems at an early stage and counteracting them to maintain general and mental health.