Prophylactic nicotinamide mononucleotide (NMN) mitigates CSDS-induced depressive-like behaviors in mice via preserving of ATP level in the mPFC.

Depression is a prevalent psychiatric disorder with accumulating evidence implicating dysregulation of extracellular adenosine triphosphate (ATP) levels in the medial prefrontal cortex (mPFC). It remains unclear whether facilitating endogenous ATP production and subsequently increasing extracellular ATP level in the mPFC can exert a prophylactic effect against chronic social defeat stress (CSDS)-induced depressive-like behaviors and enhance stress resilience. Here, we found that nicotinamide mononucleotide (NMN) treatment effectively elevated nicotinamide adenine dinucleotide (NAD+) biosynthesis and extracellular ATP levels in the mPFC. Moreover, both the 2-week intraperitoneal (i.p.) injection and 3-week oral gavage of NMN prior to exposure to CSDS effectively prevented the development of depressive-like behavior in mice. These protective effects were accompanied with the preservation of both NAD+ biosynthesis and extracellular ATP level in the mPFC. Furthermore, catalyzing ATP hydrolysis by mPFC injection of the ATPase apyrase negated the prophylactic effects of NMN on CSDS-induced depressive-like behaviors. Prophylactic NMN treatment also prevented the reduction in GABAergic inhibition and the increase in excitability in mPFC neurons projecting to the lateral habenula (LHb). Collectively, these findings demonstrate that the prophylactic effects of NMN on depressive-like behaviors are mediated by preventing extracellular ATP loss in the mPFC, which highlights the potential of NMN supplementation as a novel approach for protecting and preventing stress-induced depression in susceptible individuals.

Nifedipine-Influenced Enlargement of the Masticatory Mucosa in an Elderly Edentulous Patient: A Rare Case Report with a Two-Year Follow-Up.

Drug-influenced gingival enlargement is a common side effect associated with certain medications, particularly calcium channel blockers like nifedipine, which has been extensively documented. However, the occurrence of nifedipine-influenced masticatory mucosa overgrowth in edentulous patients is rare. Here, we present a case of nifedipine-influenced mucosal enlargement persisting in a 67-year-old edentulous patient 3 months after the extraction of all his teeth. The patient underwent flap surgery and alveoloplasty to excise the overgrown tissue, followed by complete denture restoration. The antihypertensive medication was replaced with valsartan. A 2-year follow-up revealed no recurrence of overgrowth, indicating the effectiveness of this management strategy for such clinical situation.

Biomimetic nanodecoys deliver cholesterol-modified heteroduplex oligonucleotide to target dopaminergic neurons for the treatment of Parkinson's disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the accumulation of α-synuclein (α-syn) aggregates called Lewy bodies leading to the gradual loss of dopaminergic (DA) neurons in the substantia nigra. Although α-syn expression can be attenuated by antisense oligonucleotides (ASOs) and heteroduplex oligonucleotide (HDO) by intracerebroventricular (ICV) injection, the challenge to peripheral targeted delivery of oligonucleotide safely and effectively into DA neurons remains unresolved. Here, we designed a new DNA/DNA double-stranded (complementary DNA, coDNA) molecule with cholesterol conjugation (Chol-HDO (coDNA)) based on an α-syn-ASO sequence and evaluated its silence efficiency. Further, Chol-HDO@LMNPs, Chol-HDO-loaded, cerebrovascular endothelial cell membrane with DSPE-PEG2000-levodopa modification (L-DOPA-CECm)-coated nanoparticles (NPs), were developed for the targeted treatment of PD by tail intravenous injection. CECm facilitated the blood-brain barrier (BBB) penetration of NPs, together with cholesterol escaped from reticuloendothelial system uptake, as well as L-DOPA was decarboxylated into dopamine which promoted the NPs toward the PD site for DA neuron regeneration. The behavioral tests demonstrated that the nanodecoys improved the efficacy of HDO on PD mice. These findings provide insights into the development of biomimetic nanodecoys loading HDO for precise therapy of PD. STATEMENT OF SIGNIFICANCE: The accumulation of α-synuclein (α-syn) aggregates is a hallmark of PD. Our previous study designed a specific antisense oligonucleotide (ASO) targeting human SNCA, but the traumatic intracerebroventricular (ICV) is not conducive to clinical application. Here, we further optimize the ASO by creating a DNA/DNA double-stranded molecule with cholesterol-conjugated, named Chol-HDO (coDNA), and develop a DA-targeted biomimetic nanodecoy Chol-HDO@LMNPs by engineering cerebrovascular endothelial cells membranes (CECm) with DSPE-PEG2000 and L-DOPA. The in vivo results demonstrated that tail vein injection of Chol-HDO@LMNPs could target DA neurons in the brain and ameliorate motor deficits in a PD mouse model. This investigation provides a promising peripheral delivery platform of L-DOPA-CECm nanodecoy loaded with a new Chol-HDO (coDNA) targeting DA neurons in PD therapy.

A DNA/RNA heteroduplex oligonucleotide coupling asparagine depletion restricts FGFR2 fusion-driven intrahepatic cholangiocarcinoma.

Pemigatinib, a pan-FGFR inhibitor, is approved to treat intrahepatic cholangiocarcinoma (ICC) harboring FGFR2 fusion mutations. Improving its targeting of FGFR2 fusions remains an unmet clinical need due to its pan selectivity and resistance. Here, we report a cholesterol-conjugated DNA/RNA heteroduplex oligonucleotide targeting the chimeric site in FGFR2-AHCYL1 (F-A Cho-HDO) that accumulates in ICC through endocytosis of low-density lipoprotein receptor (LDLR), which is highly expressed in both human and murine ICC. F-A Cho-HDO was determined to be a highly specific, sustainable, and well-tolerated agent for inhibiting ICC progression through posttranscriptional suppression of F-A in ICC patient-derived xenograft mouse models. Moreover, we identified an EGFR-orchestrated bypass signaling axis that partially offset the efficacy of F-A Cho-HDO. Mechanistically, EGFR-induced STAT1 upregulation promoted asparagine (Asn) synthesis through direct transcriptional upregulation of asparagine synthetase (ASNS) and dictated cell survival by preventing p53-dependent cell cycle arrest. Asn restriction with ASNase or ASNS inhibitors reduced the intracellular Asn, thereby reactivating p53 and sensitizing ICC to F-A Cho-HDO. Our findings highlight the application of genetic engineering therapies in ICC harboring FGFR2 fusions and reveal an axis of adaptation to FGFR2 inhibition that presents a rationale for the clinical evaluation of a strategy combining FGFR2 inhibitors with Asn depletion.

Myelin-associated oligodendrocytic basic protein-dependent myelin repair confers the long-lasting antidepressant effect of ketamine.

Ketamine exhibits rapid and sustained antidepressant effects. As decreased myelination has been linked to depression pathology, changes in myelination may be a pivotal mechanism underlying ketamine's long-lasting antidepressant effects. Although ketamine has a long-lasting facilitating effect on myelination, the precise roles of myelination in ketamine's sustained antidepressant effects remain unknown. In this study, we employed spatial transcriptomics (ST) to examine ketamine's lasting effects in the medial prefrontal cortex (mPFC) and hippocampus of mice subjected to chronic social defeat stress and identified several differentially expressed myelin-related genes. Ketamine's ability to restore impaired myelination in the brain by promoting the differentiation of oligodendrocyte precursor cells (OPCs) into mature oligodendrocytes was demonstrated. Moreover, we showed that inhibiting the expression of myelin-associated oligodendrocytic basic protein (Mobp) blocked ketamine's long-lasting antidepressant effects. We also illustrated that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) signaling mediated ketamine's facilitation on myelination. In addition, we found that the (R)-stereoisomer of ketamine showed stronger effects on myelination than (S)-ketamine, which may explain its longer-lasting antidepressant effects. These findings reveal novel mechanisms underlying the sustained antidepressant effects of ketamine and the differences in antidepressant effects between (R)-ketamine and (S)-ketamine, providing new insights into the role of myelination in antidepressant mechanisms.

Vibration Reduction and Explosion Control Investigation for an Ultra-Shallow Buried Tunnel under Crossing Buildings Based on HHT Analysis.

With the rapid development of underground space utilization, the excavation of new tunnels with ultra-shallow under crossing buildings using the drilling and blasting method is gradually increasing. The blasting vibration will undoubtedly affect the surrounding buildings. Reducing the impact of blasting vibration on ground buildings has become an important technical challenge faced by tunnel blasting technicians. The inlet end of the Xi'an-Chengdu High-Speed Railway Xiannvyan Tunnel passes below a village through an ultra-shallow buried section; as a result, blasting vibration control is a major concern. A design scheme for a 0.6 m footage in tunnel was proposed and verified through field tests. A 0.8 m footage scheme and 1.8 m footage millisecond interference vibration reduction scheme were proposed, respectively. Based on the HHT analysis, by comparing the surface vibration velocities and instantaneous energy obtained from the millisecond delay detonation of cutting holes and the detonation of different charging schemes, we found that the free surface, mass of single dynamite charges, and tunnel burial depth had significant influences on the surface vibration.

Inhibition of abnormal C/EBPß/α-Syn signaling pathway through activation of Nrf2 ameliorates Parkinson's disease-like pathology.

Parkinson's disease (PD) is characterized by the formation of Lewy bodies (LBs) in the brain. These LBs are primarily composed of α-Synuclein (α-Syn), which has aggregated. A recent report proposes that CCAAT/enhancer-binding proteins ß (C/EBPß) may act as an age-dependent transcription factor for α-Syn, thereby initiating PD pathologies by regulating its transcription. Potential therapeutic approaches to address PD could involve targeting the regulation of α-Syn by C/EBPß. This study has revealed that Nrf2, also known as nuclear factor (erythroid-derived 2)-like 2 (NFE2L2), suppresses the transcription of C/EBPß in SH-SY5Y cells when treated with MPP+ . To activate Nrf2, sulforaphane, an Nrf2 activator, was administered. Additionally, C/EBPß was silenced using C/EBPß-DNA/RNA heteroduplex oligonucleotide (HDO). Both approaches successfully reduced abnormal α-Syn expression in primary neurons treated with MPP+ . Furthermore, sustained activation of Nrf2 via its activator or inhibition of C/EBPß using C/EBPß-HDO resulted in a reduction of aberrant α-Syn expression, thus leading to an improvement in the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc) in mouse models induced by 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) and those treated with preformed fibrils (PFFs). The data presented in this study illustrate that the activation of Nrf2 may provide a potential therapeutic strategy for PD by inhibiting the abnormal C/EBPß/α-Syn signaling pathway.

18ß-glycyrrhetinic acid ameliorates MPTP-induced neurotoxicity in mice through activation of microglial anti-inflammatory phenotype.

RATIONALE: 18ß-glycyrrhetinic acid (18ß-GA) has been reported to have anti-inflammatory and neuroprotective effects. However, the therapeutic effect of 18ß-GA in Parkinson's disease (PD) has not been defined. OBJECTIVE: The current study aimed to evaluate the potential therapeutic effects of 18ß-GA in treating PD by mitigating 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity. RESULTS: The study showed that 18ß-GA has anti-inflammatory effects by upregulating TREM2 expression in BV2 cells, which correlates with the presence of NF-E2-related factor-2 (Nrf2). 18ß-GA reduced inflammation in BV2 cells treated with 1-methyl-4- phenylpyridinium (MPP+) by enhancing TREM2 expression, which promotes an anti-inflammatory microglial phenotype. Repeated administration of 18ß-GA in MPTP-treated mice led to therapeutic effects by enhancing TREM2 expression, resulting in the activation of anti-inflammatory microglia. Moreover, 18ß-GA attenuated the decrease in brain-derived neurotrophic factor (BDNF) levels in both MPP+-induced BV2 cells and MPTP-intoxicated mice, indicating the involvement of BDNF in the beneficial effects of 18ß-GA. CONCLUSIONS: It is probable that activating microglial anti-inflammatory response through TREM2 expression might serve as a novel therapeutic strategy for PD. Additionally, 18ß-GA seems to hold potential as a new therapeutic agent for PD.

Serine/threonine kinase TBK1 promotes cholangiocarcinoma progression via direct regulation of ß-catenin.

Cholangiocarcinoma (CCA) is a highly heterogeneous and metastatic malignancy with a poor prognosis even after curative hepatectomy. Studies exploring its pathogenesis and identifying effective therapeutic targets are urgently needed. In this study, we found that TANK-binding kinase 1 (TBK1), a serine/threonine-protein kinase, showed a dynamic increase during the different stages of murine spontaneous CCA carcinogenesis (hyperplasia, dysplasia, and CCA). TBK1 was upregulated in human tissues, including intrahepatic (n = 182) and extrahepatic (n = 40) CCA tissues, compared with nontumor tissues, and the elevated expression of TBK1 was positively correlated with larger tumour diameter, lymph node metastasis, and advanced TNM stage. Functional studies indicated that TBK1 promoted CCA growth and metastasis both in vitro and in vivo. TBK1 directly interacts with ß-catenin, promoting its phosphorylation at the S552 site and its nuclear translocation, which further activates EMT-related transcriptional reprogramming. GSK-8612, a TBK1 inhibitor or a kinase-inactivating mutation, effectively suppresses the above processes. In addition, we found that low-density lipoprotein receptor (LDLR), which mediates the endocytosis of cholesterol, was upregulated in CCA. Therefore, we designed a cholesterol-conjugated DNA/RNA heteroduplex oligonucleotide targeting TBK1 (Cho-TBK1-HDO), which could accumulate in CCA cells via LDLR, reduce the TBK1 mRNA level and inhibit intrahepatic metastasis of CCA. Besides, in the experimental group of 182 ICC patients, high TBK1 expression combined with high nuclear ß-catenin expression predicted a worse prognosis. In summary, TBK1 might serve as a potential prognostic biomarker and therapeutic target for patients with CCA.

Lipopolysaccharide-induced endotoxaemia during adolescence promotes stress vulnerability in adult mice via deregulation of nuclear factor erythroid 2-related factor 2 in the medial prefrontal cortex.

RATIONALE: Sepsis is a severe inflammatory response to infection that leads to long-lasting cognitive impairment and depression after resolution. The lipopolysaccharide (LPS)-induced endotoxaemia model is a well-established model of gram-negative bacterial infection and recapitulates the clinical characteristics of sepsis. However, whether LPS-induced endotoxaemia during adolescence can modulate depressive and anxiety-like behaviours in adulthood remains unclear. OBJECTIVES: To determine whether LPS-induced endotoxaemia in adolescence can modulate the stress vulnerability to depressive and anxiety-like behaviours in adulthood and explore the underlying molecular mechanisms. METHODS: Quantitative real-time PCR was used to measure inflammatory cytokine expression in the brain. A stress vulnerability model was established by exposure to subthreshold social defeat stress (SSDS), and depressive- and anxiety-like behaviours were evaluated by the social interaction test (SIT), sucrose preference test (SPT), tail suspension test (TST), force swimming test (FST), elevated plus-maze (EPM) test, and open field test (OFT). Western blotting was used to measure Nrf2 and BDNF expression levels in the brain. RESULTS: Our results showed that inflammation occurred in the brain 24 h after the induction of LPS-induced endotoxaemia at P21 but resolved in adulthood. Furthermore, LPS-induced endotoxaemia during adolescence promoted the inflammatory response and the stress vulnerability after SSDS during adulthood. Notably, the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and BDNF in the mPFC were decreased after SSDS exposure in mice treated with LPS during adolescence. Activation of the Nrf2-BDNF signalling pathway by sulforaphane (SFN), an Nrf2 activator, ameliorated the effect of LPS-induced endotoxaemia during adolescence on stress vulnerability after SSDS during adulthood. CONCLUSIONS: Our study identified adolescence as a critical period during which LPS-induced endotoxaemia can promote stress vulnerability during adulthood and showed that this effect is mediated by impairment of Nrf2-BDNF signalling in the mPFC.

Feruloylated oligosaccharides ameliorate MPTP-induced neurotoxicity in mice by activating ERK/CREB/BDNF/TrkB signalling pathway.

BACKGROUND: Feruloylated oligosaccharides (FOs) are natural esterification products of ferulic acid and oligosaccharides. STUDY DESIGN: In this study, we examined whether FOs contribute to the ensured survival of nigrostriatal dopamine neurons and inhibition of neuroinflammation in Parkinson's disease (PD). METHODS: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg) was injected intraperitoneally into mice to establish a Parkinson's disease (PD) mouse model. FOs (15 and 30 mg/kg) were orally administered daily to the MPTP-treated mice. The rotarod test, balance beam test, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), quantitative PCR (qPCR), and western blot analyses were performed to examine the neuroprotective effects of FOs on MPTP-treated mice. RESULTS: Our study indicated that FOs increased the survival of dopamine neurons in the substantia nigra pars compacta (SNc) of the MPTP-treated mice. The neuroprotective effects of FOs were accompanied by inhibited glial activation and reduced inflammatory cytokine production. The mechanistic experiments revealed that the neuroprotective effects of FOs might be mediated through the activation of the ERK/CREB/BDNF/TrkB signalling pathway. CONCLUSION: This study provides new insights into the mechanism underlying the anti-neuroinflammatory effect of phytochemicals and may facilitate the development of dietary supplements for PD patients. Our results indicate that FOs can be used as potential modulators for the prevention and treatment of PD.

The role of BDNF transcription in the antidepressant-like effects of 18ß-glycyrrhetinic acid in a chronic social defeat stress model.

BACKGROUND: Xiaoyaosan (XYS), a traditional Chinese medicine formulation, has been used in the treatment of depression. However, no studies have yet identified the active compounds responsible for its antidepressant effects in the brain. STUDY DESIGN: We investigated the antidepressants effects of XYS and identified 18ß-glycyrrhetinic acid (18ß-GA) as the primary compound present in the brain following XYS injection. Furthermore, we explored the molecular mechanisms underlying the antidepressant-like effects of both XYS and 18ß-GA. METHODS: To investigate the antidepressant-like effects of XYS and elucidate the associated molecular mechanisms, we employed various methodologies, including cell cultures, the chronic social defeat stress (CSDS) model, behavioral tests, immunoprecipitation, quantitative PCR (qPCR) assays, Western blotting assays, luciferase assays, chromatin immunoprecipitation (ChIP) assays, immunofluorescence staining, and dendritic spine analysis. RESULTS: We identified 18ß-GA as the primary compound in the brain following XYS injection. In vitro, 18ß-GA was found to bind with ERK (extracellular signal-regulated kinase), subsequently activating ERK kinase activity toward both c-Jun and cAMP response element binding protein (CREB). Moreover, 18ß-GA activated brain-derived neurotrophic factor (BDNF) transcription by stimulating nuclear factor-erythroid factor 2-related factor 2 (Nrf2), c-Jun, and CREB, while also inhibiting methyl CpG binding protein 2 (MeCP2) both in vitro and in vivo. Chronic intraperitoneal (i.p.) administration of 18ß-GA exhibited prophylactic antidepressant-like effects in a CSDS model, primarily by activating BDNF transcription in the medial prefrontal cortex (mPFC). Interestingly, a single i.p. injection of 18ß-GA produced rapid and sustained antidepressant-like effects in CSDS-susceptible mice by engaging the BDNF-tropomyosin receptor kinase B (TrkB) signaling pathway in the mPFC. CONCLUSION: These findings suggest that the activation of BDNF transcription in the mPFC underlies the antidepressant-like effects of 18ß-GA, a key component of XYS in the brain.

Nrf2 regulates the arginase 1+ microglia phenotype through the initiation of TREM2 transcription, ameliorating depression-like behavior in mice.

The expression of the triggering receptor on myeloid cell-2 (TREM2) knockdown in microglia from the lateral habenula (LHb) reportedly induces depression-like behaviors in mice. However, the key molecular mechanism that mediates major depressive disorder (MDD) pathogenesis remains elusive. We herein show that Nrf2 regulates TREM2 transcription and effects TREM2 mRNA and protein expression. The activation of Nrf2 by sulforaphane (Nrf2 activator) increases the microglial arginase 1+ phenotype by initiating TREM2 transcription in the medial prefrontal cortex (mPFC) and ameliorates depression-like behavior in CSDS mice. The knockout of Nrf2 decreases TREM2 and the microglial arginase 1+ phenotype in the mPFC of Nrf2 KO mice with depression-like behavior. Downregulating TREM2 expression decreases the microglial arginase 1+ phenotype in the mPFC, resulting in depression-like behavior in SFN-treated CSDS mice. Finally, the knockout of Nrf2 and downregulation of TREM2 expression decreases the microglial arginase 1+ phenotype in the mPFC of Nrf2 KO mice and SFN-treated CSDS mice were associated with the brain-derived neurotrophic factor (BDNF)-tropomyosin receptor kinase B (TrkB) signaling pathway. These data indicate that alterations in the interaction between Nrf2 and TREM2 may play a role in the pathophysiology of depression-like behavior in mice.

Fucosylated Chondroitin Sulfate against Parkinson's Disease through Inhibiting Inflammation Induced by Gut Dysbiosis.

Growing evidence for the importance of the gut-brain axis in Parkinson's disease (PD) has attracted researchers' interest in the possible application of microbiota-based treatment approaches. Using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model, we looked into the prospect of treating PD with fucosylated chondroitin sulfate obtained from sea cucumbers Isostichopus badionotus (fCS-Ib). We showed that giving fCS-Ib polysaccharide orally greatly reduced the motor deficits, dopamine depletion, and alpha-synuclein increase caused by MPTP in the substantia nigra (SN). It appears that the anti-PD action of fCS-Ib polysaccharide could be attained by squelching inflammation. Glial cell hyperactivation in SN and overproduction of proinflammatory substances in serum could both be suppressed by fCS-Ib polysaccharide injection. The bacterial DNA in fresh colonic feces was submitted to 16S rRNA and untargeted metabolic analyses to confirm the participation of the microbiota-gut-brain axis in the aforementioned interpretation. The findings showed that the MPTP treatment-induced decrease in norank_f_Muribaculaceae and the increase in Staphylococcus were reversed by the administration of fCS-Ib polysaccharide. The NF-κB signaling pathway was shown to be involved in the fCS-Ib polysaccharide-induced anti-inflammation. In conclusion, our research demonstrated for the first time how fCS-Ib polysaccharide combats PD by reducing inflammation caused by gut microbial dysbiosis.

Arketamine, a new rapid-acting antidepressant: A historical review and future directions.

The N-methyl-d-aspartate receptor (NMDAR) antagonist (R,S)-ketamine causes rapid onset and sustained antidepressant actions in treatment-resistant patients with major depressive disorder (MDD) and other psychiatric disorders, such as bipolar disorder and post-traumatic stress disorder. (R,S)-ketamine is a racemic mixture consisting of (R)-ketamine (or arketamine) and (S)-ketamine (or esketamine), with (S)-enantiomer having greater affinity for the NMDAR. In 2019, an esketamine nasal spray by Johnson & Johnson was approved in the USA and Europe for treatment-resistant depression. In contrast, an increasing number of preclinical studies show that arketamine has greater potency and longer-lasting antidepressant-like effects than esketamine in rodents, despite the lower binding affinity of arketamine for the NMDAR. Importantly, the side effects, i.e., psychotomimetic and dissociative effects and abuse liability, of arketamine are less than those of (R,S)-ketamine and esketamine in animals and humans. An open-label study demonstrated the rapid and sustained antidepressant effects of arketamine in treatment-resistant patients with MDD. A phase 2 clinical trial of arketamine in treatment-resistant patients with MDD is underway. This study was designed to review the brief history of the novel antidepressant arketamine, the molecular mechanisms underlying its antidepressant actions, and future directions.

Suppression of abnormal α-synuclein expression by activation of BDNF transcription ameliorates Parkinson's disease-like pathology.

Parkinson's disease (PD) is characterized by the formation of Lewy bodies (LBs) in the brain. LBs are mainly composed of phosphorylated and aggregated α-synuclein (α-Syn). Thus, strategies to reduce the expression of α-Syn offer promising therapeutic avenues for PD. DNA/RNA heteroduplex oligonucleotides (HDOs) are a novel technology for gene silencing. Using an α-Syn-HDO that specifically targets α-Syn, we examined whether α-Syn-HDO attenuates pathological changes in the brain of mouse models of PD. Overexpression of α-Syn induced dopaminergic neuron degeneration through inhibition of cyclic AMP-responsive-element-binding protein (CREB) and activation of methyl CpG binding protein 2 (MeCP2), resulting in brain-derived neurotrophic factor (BDNF) downregulation. α-Syn-HDO exerted a more potent silencing effect on α-Syn than α-Syn-antisense oligonucleotides (ASOs). α-Syn-HDO attenuated abnormal α-Syn expression and ameliorated dopaminergic neuron degeneration via BDNF upregulation by activation of CREB and inhibition of MeCP2. These findings demonstrated that inhibition of α-Syn by α-Syn-HDO protected against dopaminergic neuron degeneration via activation of BDNF transcription. Therefore, α-Syn-HDO may serve as a new therapeutic agent for PD.

The role of MeCP2 and the BDNF/TrkB signaling pathway in the stress resilience of mice subjected to CSDS.

RATIONALE: There is accumulating evidence to support the idea that brain-derived neurotrophic factor (BDNF) is involved in stress resilience. However, the precise molecular mechanisms underlying resilience in major depressive disorder (MDD) remain unknown. OBJECTIVE: The objective of this study was to explore the role of methyl CpG binding protein 2 (MeCP2) and the BDNF/tropomyosin-receptor-kinase B (TrkB) signaling pathway in the stress resilience to chronic social defeat stress (CSDS) in mice. RESULTS: We found that the overexpression of MeCP2 inhibited BDNF transcription, resulting in BDNF mRNA and protein downregulation in neuro-2a cells. The overexpression of MeCP2 increased S80-MeCP2 and decreased S421-MeCP2, BDNF, the ratio of S133-cyclic AMP response element binding protein (CREB)/CREB and p-TrkB/TrkB expression in neuro-2a cells. In addition, using the CSDS mouse model, we found that MeCP2 mRNA levels were decreased in the medial prefrontal cortex (mPFC) of resilient mice and increased in the hippocampus of susceptible mice. BDNF exon IV promoter and BDNF mRNA levels were decreased in the mPFC and hippocampus of susceptible mice. Finally, MeCP2 and S80-MeCP2 protein levels were increased in the mPFC and hippocampus of susceptible mice, whereas the protein expression of S421-MeCP2 and BDNF, the ratio of S133-CREB/CREB, and the levels of p-TrkB/TrkB were decreased in susceptible mice. CONCLUSIONS: These data suggest that the overexpression of MeCP2 inhibits BDNF transcription in neuro-2a cells. The inhibition of MeCP2 expression and activation of the BDNF/TrkB signaling pathway may confer stress resilience in CSDS mice.

Regulation of BDNF transcription by Nrf2 and MeCP2 ameliorates MPTP-induced neurotoxicity.

Mounting evidence suggests the key role of brain-derived neurotrophic factor (BDNF) in the dopaminergic neurotoxicity of Parkinson's disease (PD). Activation of NF-E2-related factor-2 (Nrf2) and inhibition of methyl CpG-binding protein 2 (MeCP2) can regulate BDNF upregulation. However, the regulation of BDNF by Nrf2 and MeCP2 in the PD pathogenesis has not been reported. Here, we revealed that Nrf2/MeCP2 coordinately regulated BDNF transcription, reversing the decreased levels of BDNF expression in 1-methyl-4-phenylpyridinium (MPP+)-treated SH-SY5Y cells and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice. Repeated administration of sulforaphane (SFN, an Nrf2 activator) attenuated dopaminergic neurotoxicity in MPTP-treated mice through activation of BDNF and suppression of MeCP2 expression. Furthermore, intracerebroventricular injection of MeCP2-HDO, a DNA/RNA heteroduplex oligonucleotide (HDO) silencing MeCP2 expression, ameliorated dopaminergic neurotoxicity in MPTP-treated mice via activation of Nrf2 and BDNF expression. Moreover, we found decreased levels of Nrf2 and BDNF, and increased levels of MeCP2 protein expression in the striatum of patients with dementia with Lewy bodies (DLB). Interesting, there were correlations between BDNF and Nrf2 (or MeCP2) expression in the striatum from DLB patients. Therefore, it is likely that the activation of BDNF transcription by activation of Nrf2 and/or suppression of MeCP2 could be a new therapeutic approach for PD.

Expression of Human Uncoupling Protein-1 in Escherichia coli Decreases its Survival Under Extremely Acidic Conditions.

Uncoupling protein-1 (UCP1), located at the inner membrane of mitochondria, is expressed primarily in brown adipose tissue and mediates the permeability of protons through the inner mitochondrial membrane. This research examines whether human UCP1 can uncouple oxidative phosphorylation in E. coli. Recombinant human UCP1 that includes an N terminus signal peptide for the bacterial inner membrane was expressed in E. coli. Our testing showed that UCP1 functions as a proton transporter in the bacterial membrane, increasing its permeability, decrease ATP synthesis at neutral pH and reducing the viability of E. coli in markedly acidic environments. These results suggest that UCP1 can uncouple oxidative phosphorylation in E. coli. The decreased acid resistance (AR) of E. coli with UCP1 expressed in the membranes confirmed that oxidative phosphorylation plays a role in AR through the pumping of protons to regulate the intracellular pH, and demonstrate that UCP1 can be used as an uncoupler protein for bacterial metabolic research.