Cytomegalovirus antibodies are associated with mood disorders, suicide, markers of neuroinflammation, and microglia activation in postmortem brain samples

Increased expression of ER stress, inflammasome activation, and mitochondrial biogenesis-related genes in peripheral blood mononuclear cells in major depressive disorder

A subset of major depressive disorder (MDD) is characterized by immune system dysfunction, but the intracellular origin of these immune changes remains unclear. Here we tested the hypothesis that abnormalities in endoplasmic reticulum (ER) stress, inflammasome activity and mitochondrial biogenesis contribute to the development of systemic inflammation in MDD. RT-qPCR was used to measure mRNA expression of key organellar genes from peripheral blood mononuclear cells (PBMCs) isolated from 186 MDD and 67 healthy control (HC) subjects. The comparative CT (2-ΔΔCT) method was applied to quantify mRNA expression using GAPDH as the reference gene. After controlling for age, sex, BMI, and medication status using linear regression models, expression of the inflammasome (NLRC4 and NLRP3) and the ER stress (XBP1u, XBP1s, and ATF4) genes was found to be significantly increased in the MDD versus the HC group. Sensitivity analyses excluding covariates yielded similar results. After excluding outliers, expression of the inflammasome genes was no longer statistically significant but expression of the ER stress genes (XBP1u, XBP1s, and ATF4) remained significant and the mitochondrial biogenesis gene, MFN2, was significantly increased in the MDD group. NLRC4 and MFN2 were positively correlated with serum C-reactive protein concentrations, while ASC trended significant. The altered expression of inflammasome activation, ER stress, and mitochondrial biogenesis pathway components suggest that dysfunction of these organelles may play a role in the pathogenesis of MDD.

Nuclear factor kappa-B cell (NF-κB), interferon regulatory Factor, and glucocorticoid receptor pathway activation in major depressive Disorder: The role of cytomegalovirus infection

Altered activity of major immunoregulatory pathways has been reported in major depressive disorder (MDD) and is thought to underlie the elevations in circulating inflammatory mediators present in a subgroup of patients. However, the drivers of these changes in gene expression remain unclear. One potential modulator of immune function is viral infection. Here we examined the relationship between cytomegalovirus (CMV), a common herpesvirus, that has been shown to be a pathological cofactor in inflammatory disorders, and activity of key coordinators of the innate inflammatory response in MDD. We used RNAseq to characterize gene expression differences in in 79 unmedicated individuals with MDD and 80 healthy controls (HCs). A well-established bioinformatic strategy was used to quantify transcription control pathway activity based on the relative prevalence of pre-specified transcription factor-binding motifs in the promoters of differentially expressed genes. The main aim was to characterize diagnostic differences in immunoregulatory pathway activity and determine if these were related to CMV serostatus or antibody titer (viral reactivation). Significantly increased activity of interferon regulatory factor 1 (IRF1) and nuclear factor kappa-B cell (NF-κB) pathways was observed in the MDD group compared with HCs. Transcript Origin Analyses using cell-specific reference transcriptomes indicated that the MDD-associated transcriptome changes derived primarily from myeloid lineage immune cells (classical and non-classical monocytes). A more modest MDD-associated upregulation of glucocorticoid receptor (GR) pathway activity was also present. CMV infection/activity across the combined MDD and HC groups was weakly related to GR pathway activation but not to IRF1 and NF-κB activity; the most salient signature of CMV was activation and/or expansion of the CD8+ T-cell population. The elevated MDD-associated NF-κB (but not IRF1) activity was markedly attenuated after controlling for CMV antibody titer or for CD8+ T-cell prevalence. At least some of the NF-κB signal in MDD may be attributable to the cellular immune response to CMV, suggesting that CMV infection may be one of several pathways contributing to inflammation in depression. The pronounced activation of the antiviral IRF-1 pathway in MDD suggests the contribution of viral processes although this specific antiviral effect was not specific to CMV.CMV may indirectly drive interferon responses by impairing T-cell control of other viral infections.

Susceptibility of Mouse Brain to MCMV Infection and Neuroinflammation During Ontogeny

Human cytomegalovirus (HCMV) rarely infects the brain following infection of adult individuals. However, the virus readily infects the brain during congenital HCMV (cHCMV) infection, frequently causing severe neurodevelopmental and neurological sequelae. Interestingly, although the incidence of cHCMV infection is 0.5-1%, the proportion of congenitally infected individuals in which the virus manages to gain access to the brain is unknown. In this study, we used infection of mice with mouse cytomegalovirus (MCMV), the most commonly used experimental system for modeling HCMV disease in humans, to determine the impact of age on the susceptibility of the brain to cytomegalovirus infection and infection-mediated neuroinflammation. We demonstrate that infection of mice during various stages of neonatal development can lead to CMV neuroinvasion and inflammation. In contrast, MCMV infection does not result in MCMV neuroinvasion and neuroinflammation in weanling and adult mice. The obtained results establish a basis for elucidating the mechanisms of CMV neuroinvasion and the deleterious inflammatory response during ontogeny.

Association of HHV‑6 reactivation and SLC6A3 (C>T, rs40184), BDNF (C>T, rs6265), and JARID2 (G>A, rs9383046) single nucleotide polymorphisms in depression

Major depressive disorder (MDD) is a global health concern with a complex etiology involving genetic, environmental and infectious factors. The exact cause of MDD remains unknown. The present study explored the association between genetic factors, human herpesvirus 6 (HHV-6) and MDD. The present study analyzed single nucleotide polymorphisms (SNPs) and HHV-6 viral load in oral buccal samples from patients with MDD (with and without blood relatives with MDD) and healthy controls. The study used high-resolution melt analysis to examine rs40184 (C>T) in the solute carrier family 6 member 3 (SLC6A31) gene, rs6265 (C>T) in the brain-derived neurotrophic factor (BDNF) gene and rs9383046 (G>A) in the jumonji and AT-rich interaction domain-containing 2 (JARID2) gene. HHV-6 infection and viral load was assessed using the quantitative PCR. Whole-exome sequencing was used to examine SNPs. The variant alleles of SNPs rs40184 [18/40 (45.00) vs. 29/238 (12.55%)] and rs6265 [30/54 (55.46) vs. 117/292 (40.06%)] were significantly more common in patients with MDD than in healthy controls, indicating they may be probable hereditary risk factors for MDD. HHV-6 positivity was significantly more common in carriers of the G/A genotype (12/15, 80%) than carriers of the G/G genotype (75/363, 20.7%) for rs9383046, implying that genetic variations may affect HHV-6 risk and MDD onset. Similarly, HHV-6 viral loads were significantly higher in carriers of the G/A genotype (99,990.85±118,392.64 copies/ng DNA) than carriers of the G/G genotype (48,249.30±101,216.28 copies/ng DNA) for rs9383046. Whole-exome sequencing identified two SNPs in JARID2 (rs11757092 and rs9383050) associated with MDD, highlighting its genetic complexity. The present study helps explain the complex interactions between HHV-6 infection, genetics and MDD onset, improving understanding of how SNPs in JARID2 contribute to HHV-6 infection and MDD onset; these findings may impact future approaches to diagnosing and treating MDD.

Is There such a Thing as Post-Viral Depression?: Implications for Precision Medicine

Viral infections are increasingly recognized as triggers for depressive disorders, particularly following the SARS-CoV-2 pandemic and the rise of long COVID. Viruses such as Herpes Simplex Virus (HSV), Epstein-Barr Virus (EBV), Cytomegalovirus (CMV), and Human Immunodeficiency Virus (HIV) are linked to depression through complex neurobiological mechanisms. These include immune system dysregulation, chronic inflammation, and neurotransmitter imbalances that affect brain function and mood regulation. Viral activation of the immune system leads to the release of pro-inflammatory cytokines, resulting in neuroinflammation and associated depressive symptoms. Furthermore, specific viruses can disrupt neurotransmitter systems, including serotonin, dopamine, and glutamate, all of which are essential for mood stabilization. The unique interactions of different viruses with these systems underscore the need for virus-specific therapeutic approaches. Current broad-spectrum treatments often overlook the precise neurobiological pathways involved in post-viral depression, reducing their efficacy. This review emphasizes the need to understand these virus-specific interactions to create tailored interventions that directly address the neurobiological effects induced by each type of virus. These interventions may include immunomodulatory treatments that target persistent inflammation, antiviral therapies to reduce the viral load, or neuroprotective strategies that restore neurotransmitter balance. Precision medicine offers promising avenues for the effective management of virus-induced depression, providing patient-specific approaches that address the specific biological mechanisms involved. By focusing on the development of these targeted treatments, this review aims to pave the way for a new era in psychiatric care that fully addresses the root causes of depression induced by viral infections.

Serum signature of antibodies to Toxoplasma gondii, rubella virus, and cytomegalovirus in females with bipolar disorder: A cross-sectional study

BACKGROUND AND AIM

Immunity alterations have been observed in bipolar disorder (BD). However, whether serum positivity of antibodies to Toxoplasma gondii (T gondii), rubella, and cytomegalovirus (CMV) shared clinical relevance with BD, remains controversial. This study aimed to investigate this association.

METHODS

Antibody seropositivity of IgM and IgG to T gondii, rubella virus, and CMV of females with BD and controls was extracted based on medical records from January 2018 to January 2023. Family history, type of BD, onset age, and psychotic symptom history were also collected.

RESULTS

585 individuals with BD and 800 healthy controls were involved. Individuals with BD revealed a lower positive rate of T gondii IgG in the 10-20 aged group (OR = 0.10), and a higher positive rate of rubella IgG in the 10-20 (OR = 5.44) and 20-30 aged group (OR = 3.15). BD with family history preferred a higher positive rate of T gondii IgG (OR = 24.00). Type-I BD owned a decreased positive rate of rubella IgG (OR = 0.37) and an elevated positive rate of CMV IgG (OR = 2.12) compared to type-II BD, while BD with early onset showed contrast results compared to BD without early onset (Rubella IgG, OR = 2.54; CMV IgG, OR = 0.26). BD with psychotic symptom history displayed a lower positive rate of rubella IgG (OR = 0.50).

LIMITATIONS

Absence of male evidence and control of socioeconomic status and environmental exposure.

CONCLUSIONS

Differential antibody seropositive rates of T gondii, rubella, and cytomegalovirus in BD were observed.

CCR3 knockdown attenuates prolonged underwater operations-induced cognitive impairment via alleviating microglia-mediated neuroinflammation

Maintaining cognitive integrity is crucial during underwater operations, which can significantly impact work performance and risk severe accidents. However, the cognitive effects of underwater operations and their underlying mechanism remain elusive, posing great challenges to the medical protection of professionals concerned. Here, we found that a single underwater operation session affects cognition in a time-dependent model. Prolonged exposure elicits significant cognitive impairment and hippocampal dysfunction, accompanied by increased neuroinflammation. Furthermore, RNA sequencing (RNA-seq) analysis revealed the involvement of neuroinflammation and highlighted the critical role of CCR3. Knockdown of CCR3 significantly rescued cognitive impairment and hippocampal dysfunction and reversed the upregulation of pro-inflammatory cytokines, by switching the activated microglia from a pro-inflammatory to a neuroprotective phenotype. Taken together, these results highlighted the time-dependent effects of a single underwater operation session on cognitive function. Knocking down CCR3 can attenuate neuroinflammation by regulating polarization of activated microglia, thereby alleviating prolonged underwater operations-induced cognitive impairment.

Harnessing nanomedicine for modulating microglial states in the central nervous system disorders: Challenges and opportunities

Microglia are essential for maintaining homeostasis and responding to pathological events in the central nervous system (CNS). Their dynamic and multidimensional states in different environments are pivotal factors in various CNS disorders. However, therapeutic modulation of microglial states is challenging due to the intricate balance these cells maintain in the CNS environment and the blood-brain barrier's restriction of drug delivery. Nanomedicine presents a promising avenue for addressing these challenges, offering a method for the targeted and efficient modulation of microglial states. This review covers the challenges faced in microglial therapeutic modulation and potential use of nanoparticle-based drug delivery systems. We provide an in-depth examination of nanoparticle applications for modulating microglial states in a range of CNS disorders, encompassing neurodegenerative and autoimmune diseases, infections, traumatic injuries, stroke, tumors, chronic pain, and psychiatric conditions. This review highlights the recent advancements and future prospects in nanomedicine for microglial modulation, paving the way for future research and clinical applications of therapeutic interventions in CNS disorders.

Potential value and research frontiers of virus in neuroinflammation: a bibliometric and visualized analysis

Background

Neuroinflammation represents the immune response of the central nervous system to nerve injury, infection, toxin stimulation, or autoimmunity and is implicated in a wide range of neurological disorders. Viruses play a pivotal role as extrinsic biological drivers in neuroinflammation; however, numerous aspects remain unexplored. In this study, we employed bibliometric analysis to assess the current status of viral research in neuroinflammation and anticipate future research directions and emerging trends.

Methods

Conduct a comprehensive search for scholarly publications within the Web of Science Core Collection database, with search terms on neuroinflammation and virus. Apply Microsoft Excel Office, Hiplot, R (version 4.3.1), VOSviewer (version 1.6.20) and CiteSpace (6.2.R6, advanced) software for the bibliometric analysis and visualization.

Results

A total of 4230 articles and reviews on virus and neuroinflammation were identified, demonstrating a consistent upward trend over time. The United States was the country that contributed the most publications. Approximately 22274 authors from 4474 institutions contributed to the research. Johns Hopkins University leads with the highest number of publications and citations. The top three authors with the most published articles on this field are Power, C., Lane, T. E., and Buch, S. The Journal of Neuroinflammation is the most authoritative choice for researchers. The main research focuses in this field include multiple sclerosis, Parkinson's disease, blood-brain barrier, COVID-19, Alzheimer's disease, gene therapy. In recent years, stress have emerged as hot keywords, particularly depression, human immunodeficiency virus-associated neurocognitive disorders, blood-brain barrier, gut microbiota related directions, indicating a potential shift in research focus.

Conclusion

Research on the virus and neuroinflammation has attracted increasing attention in the past decade. European and American countries have been pivotal in conducting research on virus and neuroinflammation, while China has produced a significant number of publications, its impact is still limited. Stress is likely to emerge as the next area of focus in this field. The association and regulation between viral infection and psychiatric disorders are not fully understood, and further research is needed to explore the role of neuroinflammation caused by different types of viral infection and psychiatric disorders.

Human Cytomegalovirus Infection and Neurocognitive and Neuropsychiatric Health

A common infection, human cytomegalovirus (HCMV) has been associated with a variety of human diseases, including cardiovascular disease and possibly certain cancers. HCMV has also been associated with cognitive, psychiatric, and neurological conditions. Children with congenital or early-life HCMV are at risk for microcephaly, cerebral palsy, and sensorineural hearing loss, although in many cases sensorineural loss may resolve. In addition, HCMV can be associated with neurodevelopmental impairment, which may improve with time. In young, middle-aged, and older adults, HCMV has been adversely associated with cognitive function in some but not in all studies. Research has linked HCMV to Alzheimer's and vascular dementia, but again not all findings consistently support these associations. In addition, HCMV has been associated with depressive disorder, bipolar disorder, anxiety, and autism-spectrum disorder, although the available findings are likewise inconsistent. Given associations between HCMV and a variety of neurocognitive and neuropsychiatric disorders, additional research investigating reasons for the considerable inconsistencies in the currently available findings is needed. Additional meta-analyses and more longitudinal studies are needed as well. Research into the effects of antiviral medication on cognitive and neurological outcomes and continued efforts in vaccine development have potential to lower the neurocognitive, neuropsychiatric, and neurological burden of HCMV infection.

Exo-miR-144-3p as a promising diagnostic biomarker for depressive symptoms in heart failure

AIMS

The prevalence of depression is higher in heart failure (HF) patients. Early screening of depressive symptoms in HF patients and timely intervention can help to improve patients' quality of life and prognosis. This study aims to explore diagnostic biomarkers by examining the expression profile of serum exosomal miRNAs in HF patients with depressive symptoms.

METHODS

Serum exosomal RNA was isolated and extracted from 6 HF patients with depressive symptoms (HF-DS) and 6 HF patients without depressive symptoms (HF-NDS). High-throughput sequencing was performed to obtain miRNA expression profiles and target genes were predicted for the screened differentially expressed miRNAs. Biological functions of the target genes were analyzed through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, we collected serum exosomal RNAs from HF-DS (n = 20) and HF-NDS (n = 20). The differentially expressed miRNAs selected from the sequencing results were validated using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Finally, the diagnostic efficacy of the differentially expressed exosomal miRNAs for HF-DS was evaluated by using receiver operating characteristic (ROC) curves.

RESULTS

A total of 19 significantly differentially expressed exosomal miRNAs were screened by high-throughput sequencing, consisting of 12 up-regulated and 7 down-regulated exosomal miRNAs. RT-qPCR validation demonstrated that the expression level of exo-miR-144-3p was significantly down-regulated in the HF-DS group, and the expression levels of exo-miR-625-3p and exo-miR-7856-5p were significantly up-regulated. In addition, the expression level of exo-miR-144-3p was negatively correlated with the severity of depressive symptoms in HF patients, and that the area under the curve (AUC) of exo-miR-144-3p for diagnosing HF-DS was 0.763.

CONCLUSIONS

In this study, we examined the serum exosomal miRNA expression profiles of HF patients with depressive symptoms and found that lower level of exo-miR-144-3p was associated with more severe depressive symptoms. Exo-miR-144-3p is a potential biomarker for the diagnosis of HF-DS.

Increased expression of ER stress, inflammasome activation, and mitochondrial biogenesis-related genes in peripheral blood mononuclear cells in major depressive disorder

A subset of major depressive disorder (MDD) is characterized by immune system dysfunction, but the intracellular origin of these immune changes remains unclear. Here we tested the hypothesis that abnormalities in the endoplasmic reticulum (ER) stress, inflammasome activity and mitochondrial biogenesis contribute to the development of systemic inflammation in MDD. RT-qPCR was used to measure mRNA expression of key organellar genes from peripheral blood mononuclear cells (PBMCs) isolated from 186 MDD and 67 healthy control (HC) subjects. The comparative CT (2-ΔΔCT) method was applied to quantify mRNA expression using GAPDH as the reference gene. After controlling for age, sex, BMI, and medication status using linear regression models, expression of the inflammasome (NLRC4 and NLRP3) and the ER stress (XBP1u, XBP1s, and ATF4) genes was found to be significantly increased in the MDD versus the HC group. After excluding outliers, expression of the inflammasome genes was no longer statistically significant but expression of the ER stress genes (XBP1u, XBP1s, and ATF4) and the mitochondrial biogenesis gene, MFN2, was significantly increased in the MDD group. ASC and MFN2 were positively correlated with serum C-reactive protein concentrations. The altered expression of inflammasome activation, ER stress, and mitochondrial biogenesis pathway components suggest that dysfunction of these organelles may play a role in the pathogenesis of MDD.