Identification of Key Modules and Genes Associated with Major Depressive Disorder in Adolescents

Inflammation and immune system pathways as biological signatures of adolescent depression-the IDEA-RiSCo study

The biological mechanisms underlying the onset of major depressive disorder (MDD) have predominantly been studied in adult populations from high-income countries, despite the onset of depression typically occurring in adolescence and the majority of the world's adolescents living in low- and middle-income countries (LMIC). Taking advantage of a unique adolescent sample in an LMIC (Brazil), this study aimed to identify biological pathways characterizing the presence and increased risk of depression in adolescence, and sex-specific differences in such biological signatures. We collected blood samples from a risk-stratified cohort of 150 Brazilian adolescents (aged 14-16 years old) comprising 50 adolescents with MDD, 50 adolescents at high risk of developing MDD but without current MDD, and 50 adolescents at low risk of developing MDD and without MDD (25 females and 25 males in each group). We conducted RNA-Seq and pathway analysis on whole blood. Inflammatory-related biological pathways, such as role of hypercytokinemia/hyperchemokinemia in the pathogenesis of influenza (z-score = 3.464, p < 0.001), interferon signaling (z-score = 2.464, p < 0.001), interferon alpha/beta signaling (z-score = 3.873, p < 0.001), and complement signaling (z-score = 2, p = 0.002) were upregulated in adolescents with MDD compared with adolescents without MDD independently from their level of risk. The up-regulation of such inflammation-related pathways was observed in females but not in males. Inflammatory-related pathways involved in the production of cytokines and in interferon and complement signaling were identified as key indicators of adolescent depression, and this effect was present only in females.

[UBE2W overexpression promotes proliferation of intestinal mucosal cells in mice with chemically induced colitis]

OBJECTIVE

To explore the effect of UBE2W overexpression on proliferation of intestinal mucosal cells in a mouse model of dextran sulfate sodium (DSS)-induced colitis.

METHODS

In a mouse model of colitis induced by exposure to DSS in drinking water, UBE2W expression in the colon tissue was detected by RT-PCR and Western blotting. Ten mouse models of colitis were randomized for injection of adenovirus AAV2/9 myc-UBE2W or control AAV2/9 via the tail vein (n=5), and the changes in body weight were recorded and the histological score of the colon were graded using HE staining. Ki67 and BrdU expressions in the colon mucosal cells were detected with immunohistochemistry. The effect of UBE2W overexpression on proliferation of 293T and HCT116 cells was observed using CCK-8 kit.

RESULTS

Compared with normal mice, the mouse models with DSS-induced colitis showed significantly lowered expressions of UBE2W mRNA and protein in the colon tissues. The mouse models with AAV2/9 myc-UBE2W injection had a lower body weight loss than those with control AAV2/9 injection, and the difference was the most distinct on days 9 and 10 (P < 0.05). AAV2/9 myc-UBE2W injection significantly decreased the histological score (P < 0.05) and increased Ki67 and BrdU expressions in the colon mucosal cells in the mouse models (P < 0.05). In both 293T and HCT116 cells, UBE2W overexpression significantly promoted cell proliferation at 72 h and 96 h after plasmid transfection (P < 0.05).

CONCLUSION

UBE2W overexpression provide protection of the colon mucosal cells and promotes recovery of colitis in mice possibly by promoting proliferation of the colon mucosal cells.

[Recent research on the association between depressive disorder and gene polymorphisms in adolescents]

Biogenetics plays an important role in the pathogenesis of depressive disorder in adolescents. Various genetic polymorphism studies have updated the understanding of adolescent depressive disorder. However, due to the influence of gene-environment interaction and age of puberty, the influence of gene polymorphisms on adolescent depressive disorder is complicated to clarify. Investigating and clarifying the relationship between gene polymorphisms and adolescent depressive disorder will promote the research on the pathogenesis of this disorder and provide a reference for the prevention and treatment of this disorder. This article reviews the genetic polymorphisms related to adolescent depressive disorder.

Evaluation of Inflammatory Response System (IRS) and Compensatory Immune Response System (CIRS) in Adolescent Major Depression

Purpose

Nowadays, the role of two tightly interconnected systems, the inflammatory response system (IRS) and the compensatory immune response system (CIRS) in depression, is increasingly discussed. Various studies indicate pro-inflammatory activity in adolescent depression; however, there is an almost complete lack of findings about IRS and CIRS balance. Thus, we aimed to assess different IRS and CIRS indices, profiles, and IRS/CIRS ratios in drug-naïve MDD patients at adolescent age, with respect to sex.

Patients and Methods

One hundred MDD adolescents (40 boys, average age: 15.4±1.2 yrs.) and 60 controls (28 boys, average age: 15.3±1.5 yrs.) were examined. Evaluated parameters were 1. plasma levels of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, interferon gamma, tumor necrosis factor alpha (TNF-α), soluble receptor of IL-6 (sIL-6R), soluble receptors of TNF-α (sTNF-R1, sTNF-R2); 2. profiles: IL-6 trans-signaling, M1 macrophage signaling, helper T lymphocytes (Th) 1 profile, regulatory T lymphocytes (Treg)+Th2, allIRS, and allCIRS; 3. IRS vs CIRS activity ratios: TNF-α/TNF-R1, TNF-α/TNF-R2, TNF-α/sTNF-Rs (ie sTNF-R1+sTNF-R2), Th1/Th2, Th1/Treg, Th1/Th2+Treg, M1/Th2, M1/Treg, M1/Treg+Th2, allIRS/allCIRS.

Results

MDD patients showed increased IL-4, IL-10, TNF-α, sIL-6R, Treg+Th2, allIRS, allCIRS, and TNF-α/sTNF-Rs, and decreased Th1/Th2+Treg. MDD females showed increased IL-10 and TNF-α compared to control females. MDD males showed increased IL-4, IL-10, sIL-6R, Treg+Th2, and TNF-α/TNF-R1 compared to control males. Increased sTNF-R1 was found in MDD males compared to MDD females. Positive correlations were found between CDI score and sIL-6R and IL-10 in the total group and between CDI score and IL-10 in adolescent males.

Conclusion

Our study for the first time extensively evaluated IRS and CIRS interactions revealing enhanced pro-inflammatory TNF-α signaling and IL-6 trans-signaling in association with increased IL-10- and IL-4-mediated anti-inflammatory activity in first-episode depression at the adolescent age. Moreover, results reflect the sex-specific simultaneous activation of IRS and CIRS pathways in adolescent depression.

RPS6KA5 methylation predict response to 6-week treatment for adolescent MDD patients

OBJECTIVE

We aimed to investigate the effect of differentially methylated genes and chronic childhood stress on the development of depressive symptoms in Chinese adolescents, as well as to test whether methylation at baseline can be used as a predictor of remission at follow-up after six weeks of treatment.

METHODS

After recruiting 87 MDD patients and 53 healthy controls, we compared demographic and baseline clinical characteristics. The Childhood Chronic Stress Questionnaire was used to assess stress caused by early-life events. MDD patients underwent six weeks of treatment, and response to treatment was assessed using the Beck Depression Inventory-II. In addition, four MDD patients and five controls were randomly chosen for genome-wide methylation analysis.

RESULTS

The gene RPS6KA5 showed significant methylation differences between the two groups. Severity of chronic childhood stress was significantly associated with increased risk of depression in adolescents, but not with treatment response. Baseline RPS6KA5 methylation can predict remission after six weeks of treatment. We did not observe any interaction between RPS6KA5 methylation and chronic childhood stress.

CONCLUSIONS

Our results suggest that RPS6KA5 methylation can be used as a predictor of response to treatment in adolescent MDD patients. Here we offer new evidence for the role of epigenetics in early response to treatment of depression.

TRIAL REGISTRATION

ChiCTR, ChiCTR2000033402, 31/05/2020, http://www.chictr.org.cn/index.aspx.