Urinary exosomal microRNAs as predictive biomarkers for persistent psychotic-like experiences

MicroRNA dysregulation in glutamate and dopamine pathways of schizophrenia: From molecular pathways to diagnostic and therapeutic approaches

Schizophrenia is a complex psychiatric disorder, and genetic and environmental factors have been implicated in its development. Dysregulated glutamatergic and dopaminergic transmission pathways are involved in schizophrenia development. Besides genetic mutations, epigenetic dysregulation has a considerable role in dysregulating molecular pathways involved in schizophrenia. MicroRNAs (miRNAs) are small, non-coding RNAs that target specific mRNAs and inhibit their translation into proteins. As epigenetic factors, miRNAs regulate many genes involved in glutamate and dopamine signaling pathways; thereby, their dysregulation can contribute to the development of schizophrenia. Secretion of specific miRNAs from damaged cells into body fluids can make them one of the ideal non-invasive biomarkers in the early diagnosis of schizophrenia. Also, understanding the molecular mechanisms of miRNAs in schizophrenia pathogenesis can pave the way for developing novel treatments for patients with schizophrenia. In this study, we reviewed the glutamatergic and dopaminergic pathophysiology and highlighted the role of miRNA dysregulation in schizophrenia development. Besides, we shed light on the significance of circulating miRNAs for schizophrenia diagnosis and the recent findings on the miRNA-based treatment for schizophrenia.

Circulating miRNAs modulating systemic low-grade inflammation and affecting neurodegeneration

OBJECTIVE AND DESIGN

Inflammatory processes are an important part of the etiology of many chronic diseases across various medical domains, including neurodegeneration. Understanding their regulation on the molecular level represents a major challenge. Regulatory microRNAs (miRNAs), have been recognized for their role in post-transcriptionally modulating immune-related pathways serving as biomarkers for numerous diseases.

SUBJECTS AND METHODS

This study aims to investigate the association between 176 plasma-circulating miRNAs and the blood-based immune markers C-reactive protein and fibrinogen within the general population-based SHIP-TREND-0 cohort (N = 801) and assess their impact on neurodegeneration in linear regression and moderation analyses.

RESULTS

We provide strong evidence for miRNA-mediated regulation, particularly in relation to fibrinogen, identifying 48 significant miRNAs with a pronounced over-representation in chronic inflammatory and neurological diseases. Additional moderation analyses explored the influence of the APOE ε4 genotype and brain white matter neurodegeneration on the association between miRNAs and inflammation. Again, significant associations were observed for fibrinogen with special emphasize on hsa-miR-148a-3p, known to impact on neuroinflammation.

CONCLUSIONS

Our study suggests the involvement of several plasma-circulating miRNAs in regulating immunological markers while also being linked to neurodegeneration. The strong interplay between miRNAs and inflammation holds promising potential for clinical application in many immune-related neurodegenerative diseases.

'Whole-Body' Perspectives of Schizophrenia and Related Psychotic Illness: miRNA-143 as an Exemplary Molecule Implicated across Multi-System Dysfunctions

A wide array of biological abnormalities in psychotic illness appear to reflect non-cerebral involvement. This review first outlines the evidence for such a whole-body concept of schizophrenia pathobiology, focusing particularly on cardiovascular disease, metabolic syndrome and diabetes, immunity and inflammation, cancer, and the gut-brain axis. It then considers the roles of miRNAs in general and of miRNA-143 in particular as they relate to the epidemiology, pathobiology, and treatment of schizophrenia. This is followed by notable evidence that miRNA-143 is also implicated in each of these domains of cardiovascular disease, metabolic syndrome and diabetes, immunity and inflammation, cancer, and the gut-brain axis. Thus, miRNA-143 is an exemplar of what may be a class of molecules that play a role across the multiple domains of bodily dysfunction that appear to characterize a whole-body perspective of illness in schizophrenia. Importantly, the existence of such an exemplary molecule across these multiple domains implies a coordinated rather than stochastic basis. One candidate process would be a pleiotropic effect of genetic risk for schizophrenia across the whole body.

Psychotic Disorders and exosomes: An overview of current evidence and future directions

Due to its reliance on heterogeneous symptomatology, the accurate diagnosis of psychotic disorders remains a challenging task in clinical practice. Precise and early diagnosis of psychotic disorders facilitates early intervention, which has been shown to have substantial benefits for long-term outcomes. Still, the lack of specific biomarkers is an important limitation in early diagnosis and intervention. Exosomes, which act as messengers between cells, including brain cells, contain a vast array of molecules that hold promise for unveiling disorder-specific abnormalities. In this review, we discuss recent evidence highlighting the potential of circulating exosomes and brain-derived exosomes as valuable tools for the identification of accessible, non-invasive, and blood-based biomarkers of psychotic symptomatology and risk. We discuss current limitations in biomarker discovery studies focusing on exosomes. To enhance diagnosis specificity and treatment response, we also provide guidance for future investigations that need to target biomarkers of risk and relapse, as well as consider duration of untreated psychosis, biological sex, and other factors in the multifactorial biosignature of psychosis.

MicroRNAs as potential biomarkers for diagnosis of schizophrenia and influence of antipsychotic treatment

ABSTRACT

Characterized by positive symptoms (such as changes in behavior or thoughts, including delusions and hallucinations), negative symptoms (such as apathy, anhedonia, and social withdrawal), and cognitive impairments, schizophrenia is a chronic, severe, and disabling mental disorder with late adolescence or early adulthood onset. Antipsychotics are the most commonly used drugs to treat schizophrenia, but those currently in use do not fully reverse all three types of symptoms characterizing this condition. Schizophrenia is frequently misdiagnosed, resulting in a delay of or inappropriate treatment. Abnormal expression of microRNAs is connected to brain development and disease and could provide novel biomarkers for the diagnosis and prognosis of schizophrenia. The recent studies reviewed included microRNA profiling in blood- and urine-based materials and nervous tissue materials. From the studies that had validated the preliminary findings, potential candidate biomarkers for schizophrenia in adults could be miR-22-3p, -30e-5p, -92a-3p, -148b-5p, -181a-3p, -181a-5p, -181b-5p, -199b-5p, -137 in whole blood, and miR-130b, -193a-3p in blood plasma. Antipsychotic treatment of schizophrenia patients was found to modulate the expression of certain microRNAs including miR-130b, -193a-3p, -132, -195, -30e, -432 in blood plasma. Further studies are warranted with adolescents and young adults having schizophrenia and consideration should be given to using animal models of the disorder to investigate the effect of suppressing or overexpressing specific microRNAs.

MicroRNA expression profiling of urine exosomes in children with congenital cytomegalovirus infection

Congenital cytomegalovirus (cCMV) infection can damage the central nervous system in infants; however, its prognosis cannot be predicted from clinical evaluations at the time of birth. Urinary exosomes can be used to analyze neuronal damage in neuronal diseases. To investigate the extent of neuronal damage in patients with cCMV, exosomal miRNA expression in the urine was investigated in cCMV-infected infants and controls. Microarray analysis of miRNA was performed in a cohort of 30 infants, including 11 symptomatic cCMV (ScCMV), 7 asymptomatic cCMV (AScCMV), and one late-onset ScCMV cases, and 11 healthy controls (HC). Hierarchical clustering analysis revealed the distinct expression profile of ScCMV. The patient with late-onset ScCMV was grouped into the ScCMV cluster. Pathway enrichment analysis of the target mRNAs differed significantly between the ScCMV and HC groups; this analysis also revealed that pathways related to brain development were linked to upregulated pathways. Six miRNAs that significantly different between groups (ScCMV vs. HC and ScCMV vs. AScCMV) were selected for digital PCR in another cohort for further validation. Although these six miRNAs seemed insufficient for predicting ScCMV, expression profiles of urine exosomal miRNAs can reveal neurological damage in patients with ScCMV compared to those with AcCMV or healthy infants.

The role of Extracellular Genomic Materials (EGMs) in psychiatric disorders

Extracellular Genomic Materials (EGMs) are the nucleic acids secreted or released from all types of cells by endogenous or exogenous stimuli through varying mechanisms into the extracellular region and inevitably to all biological fluids. EGMs could be found as free, protein-bound, and/ or with vesicles. EGMs can potentially have immunophenotypic and/or genotypic characteristics of a cell of origin, travel to distant organs, and interact with the new microenvironment. To achieve all, EGMs might bi-directionally transit through varying membranes, including the blood-brain barrier. Such ability provides the transfer of any information related to the pathophysiological changes in psychiatric disorders in the brain to the other distant organ systems or vice versa. In this article, many aspects of EGMs have been elegantly reviewed, including their potential in diagnosis as biomarkers, application in treatment modalities, and functional effects in the pathophysiology of psychiatric disorders. The psychiatric disorders were studied under subgroups of Schizophrenia spectrum disorders, bipolar disorder, depressive disorders, and an autism spectrum disorders. EGMs provide a robust and promising tool in clinics for prognosis and diagnosis. The successful application of EGMs into treatment modalities might further provide encouraging outcomes for researchers and clinicians in psychiatric disorders.