E-box protein E2-2 is a crucial regulator of plasmacytoid DC development

TCF4 and RBFOX1 as peripheral biomarkers for the differential diagnosis and treatment of major depressive disorder

BACKGROUND

Recent genome-wide association studies on major depressive disorder (MDD) have indicated the involvement of LRFN5 and OLFM4; however, the expression levels and roles of these molecules in MDD remain unclear. The present study aimed to determine the serum levels of TCF4 and RBFOX1 in patients with MDD and to investigate whether these molecules could be used as biomarkers for MDD diagnosis.

METHODS

The study included 99 drug-naïve MDD patients, 90 drug-treated MDD patients, and 81 healthy controls (HCs). Serum TCF4 and RBFOX1 levels were measured by ELISA. Pearson's correlation analysis was conducted to determine the association between TCF4/RBFOX1 and clinical variables. Linear support vector machine classifier was used to evaluate the diagnostic capabilities of TCF4 and RBFOX1.

RESULTS

Serum TCF4 and RBFOX1 levels were substantially higher in MDD patients than in HCs and significantly lower in drug-treated MDD patients than in drug-naïve MDD patients. Moreover, serum TCF4 and RBFOX1 levels were associated with the Hamilton Depression Scale score, duration of illness, serum lipids levels, and hepatic function. Thus, both these molecules showed potential as biomarkers for MDD. TCF4 and RBFOX1 combination exhibited a higher diagnostic performance, with the mean area under the curve values of 0.9861 and 0.9936 in the training and testing sets, respectively.

LIMITATIONS

Small sample size and investigation of only the peripheral nervous system.

CONCLUSIONS

TCF4 and RBFOX1 may be involved in the pathogenesis of MDD, and their combination may serve as a diagnostic biomarker panel for MDD.

Transcriptional dynamics and epigenetic regulation of E and ID protein encoding genes during human T cell development

T cells are generated from hematopoietic stem cells through a highly organized developmental process, in which stage-specific molecular events drive maturation towards αβ and γδ T cells. Although many of the mechanisms that control αβ- and γδ-lineage differentiation are shared between human and mouse, important differences have also been observed. Here, we studied the regulatory dynamics of the E and ID protein encoding genes during pediatric human T cell development by evaluating changes in chromatin accessibility, histone modifications and bulk and single cell gene expression. We profiled patterns of ID/E protein activity and identified up- and downstream regulators and targets, respectively. In addition, we compared transcription of E and ID protein encoding genes in human versus mouse to predict both shared and unique activities in these species, and in prenatal versus pediatric human T cell differentiation to identify regulatory changes during development. This analysis showed a putative involvement of TCF3/E2A in the development of γδ T cells. In contrast, in αβ T cell precursors a pivotal pre-TCR-driven population with high ID gene expression and low predicted E protein activity was identified. Finally, in prenatal but not postnatal thymocytes, high HEB/TCF12 levels were found to counteract high ID levels to sustain thymic development. In summary, we uncovered novel insights in the regulation of E and ID proteins on a cross-species and cross-developmental level.

TRAF5 promotes plasmacytoid dendritic cell development from bone marrow progenitors

The conventional dendritic cells (cDCs) and plasmacytoid DCs (pDCs) originate from the same common dendritic cell precursor cells in the bone marrow. The pDCs produce large amounts of type 1 interferon in response to foreign nucleic acid and crucially contribute to host defense against viral infection. Tumor necrosis factor (TNF) receptor-associated factor 5 (TRAF5) is a pivotal component of various TNF receptor signaling pathways in the immune system. Although the functions of TRAF5 in T and B lymphocytes have been well studied, its roles in pDCs remains to be fully elucidated. In this study, we show that the expression of TRAF5 supports the generation of pDCs in the bone marrow and also critically contributes to the homeostasis of the pDC subset in the periphery in a cell-intrinsic manner. Furthermore, we provide evidence that TRAF5 promotes the commitment of DC precursor cells toward pDC versus cDC subsets, which is regulated by the balance of transcription factors TCF4 and ID2. Together our findings reveal that TRAF5 acts as a positive regulator of pDC differentiation from bone marrow progenitors.

Plasmacytoid dendritic cell in immunity and cancer

Plasmacytoid dendritic cells (pDCs) comprise a subset of dendritic cells characterized by their ability to produce large amount of type I interferon (IFN-I/α). Originally recognized for their role in modulating immune responses to viral stimulation, growing interest has been directed toward their contribution to tumorigenesis. Under normal conditions, Toll-like receptor (TLR)-activated pDCs exhibit robust IFN-α production and promote both innate and adaptive immune responses. In cancer, however, pDCs demonstrate an impaired response to TLR7/9 activation, decreased or absent IFN-α production and contribute to the establishment of an immunosuppressive tumor microenvironment. In addition to IFN-α production, pDCs can also act as antigen presenting cells (APCs) and regulate immune responses to various antigens. The significant role played by pDCs in regulating both the innate and adaptive components of the immune system makes them a critical player in cancer immunology. In this review, we discuss the development and function of pDCs as well as their role in innate and adaptive immunity. Finally, we summarize pDC contribution to cancer pathogenesis, with a special focus on primary malignant brain tumor, their significance in the era of immunotherapy and suggest potential strategies for pDC-targeted therapy.

The importance of TCF4 gene in the etiology of recurrent depressive disorders

BACKGROUND

A recurrent depressive disorder is one of the most commonly diagnosed disease entities among psychiatric disorders. The prevalence and morbidity of depression are constantly increasing. Numerous studies have demonstrated the role of genetic factors in the etiology of depressive disorders. Many studies are being conducted to identify genes that predispose to depression. The purpose of this study was to investigate the role of TCF4 gene in the etiology of recurrent depressive disorders and, in particular, to assess expression of the TCF4 gene at the mRNA and protein level in patients with recurrent depressive disorders versus healthy individuals.

MATERIAL AND METHODS

The examined population consisted of 170 individuals suffering from depression and 90 healthy individuals. The expressions of the TCF4 gene at the mRNA and protein level were assessed.

RESULTS

Decreased TCF4 expression at the mRNA and protein level was found in patients with depressive disorder versus healthy individuals. Expression of the studied gene was not affected by the patients' sex and age. The statistical analysis also showed no correlation between the expression of TCF4 at the mRNA and protein level and the number of episodes or the severity of symptoms. Among the clinical manifestations of depression, only the duration of the illness correlated with the expression of TCF4 at the mRNA level.

CONCLUSIONS

Expression of TCF4 at the mRNA and protein level may be significant in the pathomechanism of recurrent depressive disorder and it is not dependent on sex and age.

HEB in the spotlight: Transcriptional regulation of T-cell specification, commitment, and developmental plasticity

The development of T cells from multipotent progenitors in the thymus occurs by cascades of interactions between signaling molecules and transcription factors, resulting in the loss of alternative lineage potential and the acquisition of the T-cell functional identity. These processes require Notch signaling and the activity of GATA3, TCF1, Bcl11b, and the E-proteins HEB and E2A. We have shown that HEB factors are required to inhibit the thymic NK cell fate and that HEBAlt allows the passage of T-cell precursors from the DN to DP stage but is insufficient for suppression of the NK cell lineage choice. HEB factors are also required to enforce the death of cells that have not rearranged their TCR genes. The synergistic interactions between Notch1, HEBAlt, HEBCan, GATA3, and TCF1 are presented in a gene network model, and the influence of thymic stromal architecture on lineage choice in the thymus is discussed.

Plasmacytoid dendritic cells in antiviral immunity and autoimmunity

Plasmacytoid dendritic cells (pDCs) represent a unique and crucial immune cell population capable of producing large amounts of type I interferons (IFNs) in response to viral infection. The function of pDCs as the professional type I IFN-producing cells is linked to their selective expression of Toll-like receptor 7 (TLR7) and TLR9, which sense viral nucleic acids within the endosomal compartments. Type I IFNs produced by pDCs not only directly inhibit viral replication but also play an essential role in linking the innate and adaptive immune system. The aberrant activation of pDCs by self nucleic acids through TLR signaling and the ongoing production of type I IFNs do occur in some autoimmune diseases. Therefore, pDC may serve as an attractive target for therapeutic manipulations of the immune system to treat viral infectious diseases and autoimmune diseases.