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.

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.

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.

Short DNA/RNA heteroduplex oligonucleotide interacting proteins are key regulators of target gene silencing.

Antisense oligonucleotide (ASO)-based therapy is one of the next-generation therapy, especially targeting neurological disorders. Many cases of ASO-dependent gene expression suppression have been reported. Recently, we developed a tocopherol conjugated DNA/RNA heteroduplex oligonucleotide (Toc-HDO) as a new type of drug. Toc-HDO is more potent, stable, and efficiently taken up by the target tissues compared to the parental ASO. However, the detailed mechanisms of Toc-HDO, including its binding proteins, are unknown. Here, we developed native gel shift assays with fluorescence-labeled nucleic acids samples extracted from mice livers. These assays revealed two Toc-HDO binding proteins, annexin A5 (ANXA5) and carbonic anhydrase 8 (CA8). Later, we identified two more proteins, apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) and flap structure-specific endonuclease 1 (FEN1) by data mining. shRNA knockdown studies demonstrated that all four proteins regulated Toc-HDO activity in Hepa1-6, mouse hepatocellular cells. In vitro binding assays and fluorescence polarization assays with purified recombinant proteins characterized the identified proteins and pull-down assays with cell lysates demonstrated the protein binding to the Toc-HDO and ASO in a biological environment. Taken together, our findings provide a brand new molecular biological insight as well as future directions for HDO-based disease therapy.

Increased EphA4-ephexin1 signaling in the medial prefrontal cortex plays a role in depression-like phenotype.

Accumulating evidence suggests a role of the ephrin receptor EphA4 and the downstream protein ephexin1 in synaptic plasticity, which is implicated in depression. We examined whether EphA4-ephexin1 signaling plays a role in the pathophysiology of depression, and the antidepressant-like effect of EphA4 inhibitor rhynchophylline. We found increased ratios of p-EphA4/EphA4 and p-ephexin1/ephexin1 in the prefrontal cortex (PFC) and hippocampus but not in the nucleus accumbens (NAc), of susceptible mice after social defeat stress. Furthermore, the p-EphA4/EphA4 ratio was higher in the parietal cortex of depressed patients compared with controls. Systemic administration of rhynchophylline, produced a rapid antidepressant-like effect in a social defeat stress model by inhibiting EphA4-ephexin1 signaling and activating brain-derived neurotrophic factor-TrkB signaling in the PFC and hippocampus. Pretreatment with rhynchophylline before each social defeat stress could prevent the onset of the depression-like phenotype after repeated social defeat stress. Overexpression of EphA4 in the medial PFC owing to infection with an EphA4 adeno-associated virus caused the depression-like phenotype 3 weeks later and rhynchophylline had a rapid antidepressant-like effect in these mice. These findings suggest that increased EphA4-ephexin1 signaling in the PFC plays a role in the pathophysiology of depression.

Prophylactic effects of sulforaphane on depression-like behavior and dendritic changes in mice after inflammation.

Inflammation plays a role in the pathophysiology of depression. Sulforaphane (SFN), an isothiocyanate compound derived from broccoli, is a potent activator of the NF-E2-related factor-2 (Nrf2), which plays a role in inflammation. In this study, we examined whether the prevention effects of SFN in lipopolysaccharide (LPS) induced depression-like behavior in mice. Pretreatment with SFN significantly blocked an increase in the serum tumor necrosis factor-α (TNF-α) level and an increase in microglial activation of brain regions after a single administration of LPS (0.5 mg/kg). Furthermore, SFN significantly potentiated increased serum levels of IL-10 after LPS administration. In the tail-suspension test and forced swimming test, SFN significantly attenuated an increase of the immobility time after LPS administration. In addition, SFN significantly recovered to control levels for LPS-induced alterations in the proteins such as brain-derived neurotrophic factor, postsynaptic density protein 95 and AMPA receptor 1 (GluA1) and dendritic spine density in the brain regions. Finally, dietary intake of 0.1% glucoraphanin (a glucosinolate precursor of SFN) food during the juvenile and adolescence could prevent the onset of LPS-induced depression-like behaviors and dendritic spine changes in the brain regions at adulthood. In conclusion, these findings suggest that dietary intake of SFN-rich broccoli sprout has prophylactic effects on inflammation-related depressive symptoms. Therefore, supplementation of SFN-rich broccoli sprout could be prophylactic vegetable to prevent or minimize the relapse by inflammation in the remission state of depressed patients.

Depression-like phenotype by deletion of α7 nicotinic acetylcholine receptor: Role of BDNF-TrkB in nucleus accumbens.

The α7 subtype of nicotinic acetylcholine receptor (nAChR) plays a role in the inflammation which is implicated in depression. This study was undertaken to examine the role of α7 nAChR in depression using α7 nAChR knock-out (KO) mice. Serum levels of tumor necrosis factor-α and interlukin-1ß in KO mice were higher than wild-type mice, suggesting an inflammatory process in KO mice. α7 nAChR KO mice showed depression-like phenotype. Furthermore, KO mice showed increased brain-derived neurotrophic factor (BDNF) and its receptor TrkB signaling, as well as increased synaptogenesis and spine density in the nucleus accumbens (NAc), although BDNF-TrkB signaling and synaptogenesis were not altered in the prefrontal cortex and hippocampus. Systemic administration of the TrkB antagonist ANA-12, but not the TrkB agonist 7,8-dihydroxyflavone and the selective serotonin reuptake inhibitor fluoxetine, showed a rapid antidepressant effect in KO mice by normalizing increased synaptogenesis in the NAc. In addition, bilateral infusion of ANA-12 into NAc promoted a rapid antidepressant effect in KO mice by normalizing increased synaptogenesis in the NAc. These findings suggest that increased BDNF-TrkB signaling and synaptogenesis in the NAc by deletion of α7 nAChR plays a key role in depression.

Antidepressant effects of TBE-31 and MCE-1, the novel Nrf2 activators, in an inflammation model of depression.

The Nuclear factor (erythroid 2-derived)-like 2 (Nrf2) plays a key role in inflammation which is implicated in the pathophysiology of depression. The Nrf2 activators have antidepressant effects in animal models of depression. The present study was undertaken to examine whether TBE-31 [(±)-(4bS,8aR,10aS)-10a-ethynyl-4b,8,8-trimethyl-3,7-dioxo-3,4b,7,8,8a,9,10,10a-octahydrophenanthrene-2,6-dicarbonitrile] and MCE-1 [(±)-3-ethynyl-3-methyl-6-oxocyclohexa-1,4-dienecarbonitrile], the novel Nrf2 activators, could show antidepressant effects in inflammation model of depression. We found that TBE-31 and MCE-1 significantly potentiated nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells, in a concentration dependent manner. The Nrf2 siRNA, but not negative control of siRNA, significantly blocked the potentiating effects of TBE-31 and MCE-1 on neurite outgrowth in PC12 cells. Furthermore, oral administration of TBE-31 or MCE-1 significantly attenuated an increase in serum levels of tumor necrosis factor-α (TNF-α) after administration of lipopolysaccharide (LPS: 0.5mg/kg). In the tail-suspension test and forced swimming test, oral administration of TBE-31 or MCE-1 significantly attenuated an increase in the immobility time after LPS (0.5mg/kg) administration. These findings suggest that the novel Nrf2 activators such as TBE-31 and MCE-1 might be potential therapeutic drugs for inflammation-related depression.

Effects of escitalopram, R-citalopram, and reboxetine on serum levels of tumor necrosis factor-α, interleukin-10, and depression-like behavior in mice after lipopolysaccharide administration.

Inflammation plays a role in the pathophysiology of depression. The purpose of this study is to examine whether the selective serotonin reuptake inhibitor (SSRI) escitalopram, its inactive enantiomer R-citalopram, and selective noradrenaline reuptake inhibitor (NRI) reboxetine, show anti-inflammatory and antidepressant effects in an inflammation-induced model of depression. Pretreatment with escitalopram (1, 3, or 10mg/kg, i.p.) markedly blocked an increase in the serum levels of pro-inflammatory cytokine, tumor necrosis factor-α (TNF-α), after a single administration of lipopolysaccharide (LPS; 0.5mg/kg). Furthermore, escitalopram (3 or 10mg/kg) significantly increased the serum levels of the anti-inflammatory cytokine interleukin-10 (IL-10) by a single administration of LPS. In contrast, pretreatment with R-citalopram (10mg/kg, i.p.) or reboxetine (10mg/kg, i.p.) did not affect the alterations in serum levels of TNF-α and IL-10 after LPS administration. Co-administration of reboxetine with escitalopram did not show anti-inflammatory effects. Pretreatment with escitalopram (10mg/kg) significantly attenuated LPS-induced increase of the immobility time in the tail-suspension test (TST) and forced swimming test (FST). In contrast, pretreatment with R-citalopram (10mg/kg), or reboxetine (10mg/kg) did not alter LPS-induced increase of immobility time of TST and FST. Interestingly, co-administration of reboxetine with escitalopram did not show antidepressant effect in this model. These findings suggest that escitalopram, but not R-citalopram and reboxetine, has anti-inflammatory and antidepressant effects in LPS-treated model of depression, and that reboxetine can antagonize the effects of escitalopram in the inflammation model. Therefore, it is likely that serotonergic system plays a key role in the pathophysiology of inflammation-induced depression.

Effects of amycenone on serum levels of tumor necrosis factor-α, interleukin-10, and depression-like behavior in mice after lipopolysaccharide administration.

Accumulating evidence suggests that inflammation plays a role in the pathophysiology of depression and that anti-inflammatory substances have antidepressant effects. Amycenone is obtained from extracts of the Yamabushitake (Hericium erinaceum). The purpose of this study is to examine whether amycenone shows anti-inflammatory and antidepressant effects in an inflammation-induced mouse model of depression. First, we examined the effects of amycenone on the serum levels of the pro-inflammatory cytokine, tumor necrosis factor-α (TNF-α), and the anti-inflammatory cytokine, interleukin-10 (IL-10), after intraperitoneal administration of the bacterial endotoxin lipopolysaccharide (LPS). Oral administration of amycenone (50, 100, or 200mg/kg) markedly blocked an increase in the serum TNF-α levels after a single administration of LPS (0.5mg/kg). Furthermore, amycenone (200mg/kg) markedly increased the serum IL-10 levels by a single administration of LPS (0.5mg/kg). Next, we examined the effects of amycenone on depression-like behaviors in the tail-suspension test (TST) and forced swimming test (FST). Pretreatment with amycenone (200mg/kg) significantly attenuated LPS (0.5mg/kg)-induced increase of the immobility time by the TST and FST, indicating antidepressant effects of amycenone. In addition, oral administration of paroxetine (30mg/kg) showed anti-inflammatory and antidepressant effects in the same model. These findings suggest that amycenone has antidepressant effects in LPS-induced inflammation model of depression. Therefore, amycenone could represent a potential supplement to prevent inflammation-related depression.

In vivo tracking of human placenta derived mesenchymal stem cells in nude mice via ¹4C-TdR labeling.

BACKGROUND: In order to shed light on the regenerative mechanism of mesenchymal stem cells (MSCs) in vivo, the bio-distribution profile of implanted cells using a stable and long-term tracking method is needed. We herein investigated the bio-distribution of human placental deciduas basalis derived MSCs (termed as PDB-MSCs) in nude mice after intravenous injection by carbon radioisotope labeling thymidine ((14)C-TdR), which is able to incorporate into new DNA strands during cell replication. RESULTS: The proliferation rate and radioactive emission of human PDB-MSCs after labeled with different concentrations of (14)C-TdR were measured. PDB-MSCs labeled with 1 µCi possessed high radioactivity, and the biological characteristics (i.e. morphology, colony forming ability, differentiation capabilities, karyotype and cell cycle) showed no significant changes after labeling. Thus, 1 µCi was the optimal concentration in this experimental design. In nude mice, 1 × 10(6) (14)C-TdR-labeled PDB-MSCs were injected intravenously and the organs were collected at days 1, 2, 3, 5, 30 and 180 after injection, respectively. Radiolabeled PDB-MSCs were found mainly in the lung, liver, spleen, stomach and left femur of the recipient nude mice at the whole observation period. CONCLUSIONS: This work provided solid evidence that (14)C-TdR labeling did not alter the biological characteristics of human placental MSCs, and that this labeling method has potential to decrease the signal from non-infused or dead cells for cell tracking. Therefore, this labeling technique can be utilized to quantify the infused cells after long-term follow-up in pre-clinical studies.

Peripheral interleukin-6 promotes resilience versus susceptibility to inescapable electric stress.

OBJECTIVE: Accumulating evidences suggest that pro-inflammatory cytokines such as interleukin-6 (IL-6) play a role in the pathophysiology of depression. In the learned helplessness (LH) paradigm, ~35% rats are resilient to inescapable stress. METHODS: Levels of IL-6 in the serum and medial prefrontal cortex (mPFC) of LH rats (susceptible) and non-LH rats (resilience) were measured using enzyme-linked immunosorbent assay and western blot analysis, respectively. RESULTS: Serum levels of IL-6 in the LH rats were significantly higher than those of control and non-LH rats. In contrast, tissue levels of IL-6 in the mPFC were not different among three groups. CONCLUSION: The results suggest that peripheral IL-6 may contribute to resilience versus susceptibility to inescapable stress.

Effects of Brilliant Blue G on Serum Tumor Necrosis Factor-α Levels and Depression-like Behavior in Mice after Lipopolysaccharide Administration.

OBJECTIVE: Accumulating evidence suggests that inflammation plays a role in the pathophysiology of major depression. The adenosine triphosphate (ATP)-sensitive P2X7 receptor (P2X7R) plays a crucial role in microglial activation caused by inflammation. The dye brilliant blue G (BBG) is a P2X7R antagonist. This study examined whether BBG shows antidepressant effects in an inflammation-induced model of depression. METHODS: We examined the effects of BBG (12.5, 25, or 50 mg/kg) on serum tumor necrosis factor-α (TNF-α) levels after administering the bacterial endotoxin lipopolysaccharide (LPS; 0.5 mg/kg) and the effects of BBG (50 mg/kg) on depression-like behavior in the tail-suspension test (TST) and forced swimming test (FST). RESULTS: Pretreatment with BBG (12.5, 25, or 50 mg/kg) significantly blocked the increase in serum TNF-α levels after a single dose of LPS (0.5 mg/kg). Furthermore, BBG (50 mg/kg) significantly attenuated the increase in immobility time in the TST and FST after LPS (0.5 mg/kg) administration. CONCLUSION: The results suggest that BBG has anti-inflammatory and antidepressant effects in mice after LPS administration. Therefore, P2X7R antagonists are potential therapeutic drugs for inflammation-related major depression.

[Reconstruction of forefoot skin defect with island flap pedicled with lateral tarsal artery].

OBJECTIVE: To investigate the therapeutic effect of island flap pedicled with lateral tarsal artery for forefoot skin defect. METHODS: From March 2007 to January 2009, 12 cases with forefoot skin defects were treated by reversed island flap pedicled with lateral tarsal artery. RESULTS: All the flaps survived completely with a followed-up period of 8-22 months, 13 months in average. The flaps and skin grafts had soft texture and a similar color as the surrounding skin. The flaps had a suitable thickness with deep pain sensation. Shallow touch and pain sensation recovered in the skin graft and within 1-2 cm of the flap edge, which was graded as S1-S2. There was no problem in shoes-wearing and walking. No flap ulcer happened. CONCLUSION: Island flap pedicled with lateral tarsal artery is suitable for forefoot skin defect, leaving less morbidity to donor site.