Effect of Inhibition of DNA Methylation Combined with Task-Specific Training on Chronic Stroke Recovery.

To develop new rehabilitation therapies for chronic stroke, this study examined the effectiveness of task-specific training (TST) and TST combined with DNA methyltransferase inhibitor in chronic stroke recovery. Eight weeks after photothrombotic stroke, 5-Aza-2'-deoxycytidine (5-Aza-dC) infusion was done on the contralesional cortex for four weeks, with and without TST. Functional recovery was assessed using the staircase test, the cylinder test, and the modified neurological severity score (mNSS). Axonal plasticity and expression of brain-derived neurotrophic factor (BDNF) were determined in the contralateral motor cortex. TST and TST combined with 5-Aza-dC significantly improved the skilled reaching ability in the staircase test and ameliorated mNSS scores and cylinder test performance. TST and TST with 5-Aza-dC significantly increased the crossing fibers from the contralesional red nucleus, reticular formation in medullar oblongata, and dorsolateral spinal cord. Mature BDNF was significantly upregulated by TST and TST combined with 5-Azd-dC. Functional recovery after chronic stroke may involve axonal plasticity and increased mature BDNF by modulating DNA methylation in the contralesional cortex. Our results suggest that combined therapy to enhance axonal plasticity based on TST and 5-Aza-dC constitutes a promising approach for promoting the recovery of function in the chronic stage of stroke.

Association between salivary mature brain-derived neurotrophic factor and psychological distress in healthcare workers.

INTRODUCTION: Previous studies have suggested association between brain-derived neurotrophic factor (BDNF) and the stress level of workers. However, no studies have investigated the potential of salivary mature BDNF (mBDNF) level as a noninvasive biomarker for psychological distress. This study aimed to explore the reliability of salivary mBDNF as a biomarker for psychological distress in healthcare workers. Furthermore, we examined the relationship between salivary and plasma mBDNF levels and their correlation with age, sex, body mass index (BMI), and exercise habits. METHODS: Fifty-one healthy healthcare workers (26 men) from the University of Occupational and Environmental Health, Japan, participated in this study. In this cross-sectional study, participants provided demographic information. Psychological distress was assessed using the Kessler 6 (K6). Saliva and blood samples were collected, and mBDNF was measured by ELISA. Spearman's rank correlation coefficient was performed to analyze the relationship between mBDNF (saliva and plasma) and K6. Statistical analyses were conducted using Stata 17.0, and a significance level of p < .05 was applied. RESULTS: The median K6 score was 1 (interquartile range [IQR]: 0-3). The median (IQR) salivary mBDNF was 1.36 (1.12-1.96) pg/mL, whereas the mean (standard deviation) plasma mBDNF was 1261.11 (242.98) pg/mL. No correlation was observed between salivary and plasma mBDNF concentrations or with the K6 score. Additionally, there were no associations between salivary or plasma mBDNF concentrations and age, sex, or exercise habits. Finally, an association between plasma mBDNF concentration and BMI was found only in univariate analysis. CONCLUSION: Our findings indicate that salivary mBDNF can be accurately measured noninvasively in healthcare workers. Within our study sample, salivary mBDNF did not demonstrate any correlation with K6 and plasma mBDNF. Future studies with a larger study sample and a diverse study population consisting of healthy participants and patients with psychiatric disorders are warranted.

Increased serum levels of mBDNF in women with minimal and mild endometriosis have no predictive power for the disease.

The objective of our pilot clinical, prospective study was to determine the serum levels of mature brain-derived neurotrophic factor, in of women with endometriosis and controls and explore whether mature brain-derived neurotrophic factor is a potential biomarker for the disease. The patients were selected from the Endometriosis Marker Austria prospective cohort study conducted at the tertiary referral certified Endometriosis Center of the Medical University of Vienna. All women underwent laparoscopic surgery because there was a suspicion of endometriosis, or the women had pelvic pain, adnexal cysts, unexplained infertility, or uterine fibroids. Our main outcome parameter was total levels of mature brain-derived neurotrophic factor in serum, measured using ELISA. Our results show that serum levels of mature brain-derived neurotrophic factor are significantly higher in women with endometriosis compared to women without endometriosis. The mean serum protein levels are significantly higher in women with rAFS stage I and II endometriosis, whereas no difference was found in women with stage III and IV endometriosis and controls. Postoperative follow-up at 6-10 weeks revealed that surgical intervention leads to equilibration of the levels of secreted mature brain-derived neurotrophic factor between women with and without endometriosis. The difference between serum mature brain-derived neurotrophic factor levels of women with endometriosis compared to women without endometriosis is independent of menstrual cycle phase and overall self-reported pelvic pain. ROC-curve analysis showed that, the mature brain-derived neurotrophic factor is not a useful biomarker for endometriosis. In conclusion, although women with stage I and II endometriosis have increased levels of mature brain-derived neurotrophic factor in serum compared to controls, the difference is not predictive for the disease. Impact statement Endometriosis is a disease that can have a significant impact on the quality of life of affected women. The gold standard for diagnosis to this day remains visualization through laparoscopic surgery with histological verification. Current studies are attempting to find a biomarker with high sensitivity and specificity, which would bypass the surgery-associated risks and would significantly reduce costs. In an attempt to elucidate whether mature serum BDNF can serve as diagnostic marker for the disease, we compared the levels of the protein in women with endometriosis to endometriosis-free controls. While our results showed that serum concentrations of the mature protein were significantly higher in women with endometriosis, we did not find this marker to have the sensitivity or specificity needed in order to allow a reliable diagnosis.

Recent advance in role and treatment of brain-derived neurotrophic factor imbalance in neurodegenerative diseases / 中华神经医学杂志

The two forms of brain-derived neurotrophic factor (BDNF), mature BDNF (mBDNF) and BDNF precursor (proBDNF), bind to corresponding receptors and mediate a series of biological signals, which play important roles in proliferation, survival and apoptosis. More and more studies have focused on the role of unbalanced transformation from proBDNF to mBDNF in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, as well as their potential as biomarkers and treatment targets. This article reviews the mechanism and therapeutic application of BDNF and proBDNF/mBDNF imbalance in the above-mentioned neurodegenerative diseases to provide new perspective and approach for the pathogenesis, early diagnosis and treatment of neurodegenerative diseases such as AD and PD.

Dopamine D3 receptor deletion increases tissue plasminogen activator (tPA) activity in prefrontal cortex and hippocampus.

Considerable evidence indicates that dopamine (DA) influences tissue plasminogen activator (tPA)-mediated proteolytic processing of the precursor of brain-derived neurotrophic factor (proBDNF) into mature BDNF (mBDNF). However, specific roles in this process for the dopamine D3 receptor (D3R) and the underlying molecular mechanisms are yet to be fully characterized. In the present study, we hypothesized that D3R deletion could influence tPA activity in the prefrontal cortex and hippocampus. Using D3R knockout (D3(-/-)) mice, we show that receptor inactivation is associated with increased tPA expression/activity both in the prefrontal cortex and, to a greater extent, in the hippocampus. Augmented tPA expression in D3(-/-) mice correlated with increased BDNF mRNA levels, plasmin/plasminogen protein ratio and the conversion of proBDNF into mBDNF, as well as enhanced tPA and mBDNF immunoreactivity, as determined by quantitative real time polymerase chain reaction (qRT-PCR), immunoblot and immunohistochemistry. In addition, when compared to wild-type controls, D3(-/-) mice exhibited increased basal activation of the canonical cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)-driven Akt/cAMP-response element-binding protein (CREB) signaling cascade, as determined by the increased Akt phosphorylation both at Thr304 and Ser473 residues, of DA and cAMP-regulated protein of 32kDa (DARPP-32) at Thr34 and a phosphorylation state-dependent inhibition of glycogen synthetase kinase-3ß (GSK-3ß) at Ser9, a substrate of Akt whose constitutive function impairs normal CREB transcriptional activity through phosphorylation at its Ser129 residue. Accordingly, CREB phosphorylation at Ser133 was significantly increased in D3(-/-) mice, whereas the GSK-3ß-dependent phosphorylation at Ser129 was diminished. Altogether, our finding reveals that mice lacking D3Rs show enhanced tPA proteolytic activity on BDNF which may involve, at least in part, a potentiated Akt/CREB signaling, possibly due to hindered GSK-3ß activity.