NADPH-oxidase 4 gene over-expression in peripheral blood lymphocytes of the schizophrenia patients

Abstract

Introduction Increased systemic oxidative stress is common in schizophrenia (SZ) patients. NADPH-oxidase 4 (NOX4) is the cell oxidoreductase, catalyzing the hydrogen peroxide formation. Presumably, NOX4 is the main oxidative stress factor in a number of diseases such as cardiovascular diseases and cancer. We hypothesized that NOX4 may be involved in the oxidative stress development caused by the disease in the schizophrenic patients’ peripheral blood lymphocytes (PBL). Materials and methods The SZ group included 100 patients (68 men and 32 women aged 28 ± 11 years). The control group included 60 volunteers (35 men and 25 women aged 25 ± 12 years). Flow cytometry analysis (FCA) was used for DNA damage markers (8-oxodG, ɣH2AX), pro- and antiapoptotic proteins (BAX1 and BCL2) and the master-regulator of anti-oxidant response NRF2 detection in the lymphocytes of the untreated SZ patients (N = 100) and the healthy control (HC, N = 60). FCA and RT-qPCR were used for NOX4 and RNANOX4 detection in the lymphocytes. RT-qPCR was used for mtDNA quantitation in peripheral blood mononuclear cells. Cell-free DNA concentration was determined in blood plasma fluorimetrically. Results 8-oxodG, NOX4, and BCL2 levels in the PBL in the SZ group were higher than those in the HC group (p < 0.001). ɣH2AX protein level was increased in the subgroup with high 8-oxodG (p<0.02) levels and decreased in the subgroup with low 8-oxodG (p <0.0001) levels. A positive correlation was found between 8-oxodG, ɣH2AX and BAX1 levels in the SZ group (p <10−6). NOX4 level in lymphocytes did not depend on the DNA damage markers values and BAX1 and BCL2 proteins levels. In 15% of PBL of the HC group a small cellular subfraction was found (5–12% of the total lymphocyte pool) with high DNA damage level and elevated BAX1 protein level. The number of such cells was maximal in PBL samples with low NOX4 protein levels. Conclusion Significant NOX4 gene expression was found a in SZ patients’ lymphocytes, but the corresponding protein is probably not a cause of the DNA damage.

Circulating Cell-Free DNA Levels in Psychiatric Diseases: A Systematic Review and Meta-Analysis

“…For the same reason, one report on cf-gDNA was excluded from the DDs group [ 36 ], as the remaining studies analyzed cf-mtDNA. Ultimately, the following numbers of reports were included in the meta-analysis: schizophrenia, 8 [ 24 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ]; BD, 4 [ 25 , 35 , 43 , 44 ]; DDs, 5 [ 35 , 45 , 46 , 47 , 48 ]. The total number of individual studies included in the meta-analysis was sixteen because some reports considered several diseases simultaneously.…”

“…Therefore, we divided all reports depending on the type of analyzed cfDNA. As a result, the total cfDNA was investigated in 6 studies [ 37 , 38 , 39 , 40 , 41 , 42 ] and cf-gDNA in three reports in the case of schizophrenia [ 24 , 36 , 42 ]. There were insufficient data for a meta-analysis of cf-mtDNA in schizophrenia (only two studies) [ 34 , 35 ].…”

“…The column method for cfDNA isolation was used in all reports for BD and DDs. In the case of schizophrenia, three of the eight studies used the column method [ 24 , 36 , 38 ], four used organic solvents [ 37 , 39 , 40 , 41 ], and one used magnetic particles [ 42 ] for DNA extraction. The fluorescent detection method was primarily used to analyze the total cfDNA in schizophrenia (only one report used fluorescence correlation spectroscopy) [ 38 ].…”

“…The cfDNA concentration was presented in various units of measurement. Eight studies reported cfDNA concentrations as ng/mL (or pg/mL) [ 24 , 36 , 37 , 39 , 40 , 41 , 42 , 48 ], five as copies/µL [ 35 , 43 , 44 , 46 , 47 ], two as GE/mL (or U/mL) [ 25 , 45 ], and one as nM [ 38 ]. All selected studies were published between 2015 and 2022.…”

In Vitro Analysis of Biological Activity of Circulating Cell-Free DNA Isolated from Blood Plasma of Schizophrenic Patients and Healthy Controls—Part 2: Adaptive Response

“…It is the major factor of oxidative stress in a number of disorders [ 38 ]. Significant expression of NOX4 gene was found in the lymphocytes obtained from SZ patients [ 39 ].…”