Assessing risk stratification in long-term outcomes of rectal neuroendocrine tumors following endoscopic resection: a multicenter retrospective study.

OBJECTIVES: While endoscopic resection of rectal neuroendocrine tumors (NETs) has significantly increased, long-term data on risk factors for recurrence are still lacking. Our aim is to analyze the long-term outcomes of patients with rectal NETs after endoscopic resection through risk stratification. METHODS: In this multicenter retrospective study, we included patients who underwent endoscopic resection of rectal NETs from 2009 to 2018 and were followed for ≥12 months at five university hospitals. We classified the patients into three risk groups according to the clinicopathological status of the rectal neuroendocrine tumors: low, indeterminate, and high. The high-risk group was defined if the tumors have any of the followings: size ≥ 10 mm, lymphovascular invasion, muscularis propria or deeper invasion, positive resection margins, or mitotic count ≥2/10. RESULTS: A total of 346 patients were included, with 144 (41.6%), 121 (35.0%), and 81 (23.4%) classified into the low-, indeterminate-, and high-risk groups, respectively. Among the high-risk group, seven patients (8.6%) received salvage treatment 28 (27-67) days after the initial endoscopic resection, with no reported extracolonic recurrence. Throughout the follow-up period, 1.1% (4/346) of patients experienced extracolonic recurrences at 56.5 (54-73) months after the initial endoscopic resection. Three of these patients (75%) were in the high-risk group and did not undergo salvage treatment. The risk of extracolonic recurrence was significantly higher in the high-risk group compared to the other groups (p = 0.039). CONCLUSION: Physicians should be concerned about the possibility of metastasis during long-term follow-up of high-risk patients and consider salvage treatment.

Deep learning in negative small-bowel capsule endoscopy improves small-bowel lesion detection and diagnostic yield.

OBJECTIVES: Although several studies have shown the usefulness of artificial intelligence to identify abnormalities in small-bowel capsule endoscopy (SBCE) images, few studies have proven its actual clinical usefulness. Thus, the aim of this study was to examine whether meaningful findings could be obtained when negative SBCE videos were reanalyzed with a deep convolutional neural network (CNN) model. METHODS: Clinical data of patients who received SBCE for suspected small-bowel bleeding at two academic hospitals between February 2018 and July 2020 were retrospectively collected. All SBCE videos read as negative were reanalyzed with the CNN algorithm developed in our previous study. Meaningful findings such as angioectasias and ulcers were finally decided after reviewing CNN-selected images by two gastroenterologists. RESULTS: Among 202 SBCE videos, 103 (51.0%) were read as negative by humans. Meaningful findings were detected in 63 (61.2%) of these 103 videos after reanalyzing them with the CNN model. There were 79 red spots or angioectasias in 40 videos and 66 erosions or ulcers in 35 videos. After reanalysis, the diagnosis was changed for 10 (10.3%) patients who had initially negative SBCE results. During a mean follow-up of 16.5 months, rebleeding occurred in 19 (18.4%) patients. The rebleeding rate was 23.6% (13/55) for patients with meaningful findings and 16.1% (5/31) for patients without meaningful findings (P = 0.411). CONCLUSION: Our CNN algorithm detected meaningful findings in negative SBCE videos that were missed by humans. The use of deep CNN for SBCE image reading is expected to compensate for human error.

From Pristine to Heteroatom-Doped Graphene Quantum Dots: An Essential Review and Prospects for Future Research.

Graphene quantum dots (GQDs) are carbon-based zero-dimensional materials that have received considerable scientific interest due to their exceptional optical, electrical, and optoelectrical properties. Their unique electronic band structures, influenced by quantum confinement and edge effects, differentiate the physical and optical characteristics of GQDs from other carbon nanostructures. Additionally, GQDs can be synthesized using various top-down and bottom-up approaches, distinguishing them from other carbon nanomaterials. This review discusses recent advancements in GQD research, focusing on their synthesis and functionalization for potential applications. Particularly, various methods for synthesizing functionalized GQDs using different doping routes are comprehensively reviewed. Based on previous reports, current challenges and future directions for GQDs research are discussed in detail herein.

Quantitative multiplex real-time polymerase chain reaction assay for the detection of Helicobacter pylori and clarithromycin resistance.

BACKGROUND: Identifying clarithromycin resistance is essential for eradicating Helicobacter pylori (HP). Therefore, we evaluated the performance of Allplex™ H.pylori & ClariR Assay (Allplex™) for diagnosing and detecting clarithromycin resistance in HP. METHODS: Subjects who underwent esophagogastroduodenoscopy between April 2020 and August 2021 at Incheon St. Mary's hospital were enrolled in this study. The diagnostic performances of Allplex™ and dual priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) were compared with sequencing as the gold standard. RESULTS: A total of 142 gastric biopsy samples were analyzed. Gene sequencing revealed 124 HP infections, 42 A2143G mutations, 2 A2142G mutations, one dual mutation, and no A2142C mutation. DPO-PCR showed 96.0% sensitivity and 100.0% specificity for HP detection; the corresponding rates for Allplex™ were 99.2% and 100.0%. DPO-PCR showed 88.3% sensitivity and 82.0% specificity for A2143G mutation, and Allplex™ showed 97.6% and 96.0%. The Cohen's Kappa coefficient for overall test results was 0.56 for DPO-PCR and 0.95 for Allplex™. CONCLUSION: Allplex™ showed comparable diagnostic performance with direct gene sequencing and non-inferior diagnostic performance to DPO-PCR. Further research is required to confirm whether Allplex™ is an effective diagnostic tool for the eradication of HP.

A natural variation in the RNA polymerase of severe fever with thrombocytopenia syndrome virus enhances viral replication and in vivo virulence.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease with high mortality in Eastern Asia. The disease is caused by the SFTS virus (SFTSV), also known as Dabie bandavirus, which has a segmented RNA genome consisting of L, M, and S segments. Previous studies have suggested differential viral virulence depending on the genotypes of SFTSV; however, the critical viral factor involved in the differential viral virulence is unknown. Here, we found a significant difference in viral replication in vitro and virulence in vivo between two Korean isolates belonging to the F and B genotypes, respectively. By generating viral reassortants using the two viral strains, we demonstrated that the L segment, which encodes viral RNA-dependent RNA polymerase (RdRp), is responsible for the enhanced viral replication and virulence. Comparison of amino acid sequences and viral replication rates revealed a point variation, E251K, on the surface of RdRp to be the most significant determinant for the enhanced viral replication rate and in vivo virulence. The effect of the variation was further confirmed using recombinant SFTSV generated by reverse genetic engineering. Therefore, our results indicate that natural variations affecting the viral replicase activity could significantly contribute to the viral virulence of SFTSV.

Glycosylation generates an efficacious and immunogenic vaccine against H7N9 influenza virus.

Zoonotic avian influenza viruses pose severe health threats to humans. Of several viral subtypes reported, the low pathogenic avian influenza H7N9 virus has since February 2013 caused more than 1,500 cases of human infection with an almost 40% case-fatality rate. Vaccination of poultry appears to reduce human infections. However, the emergence of highly pathogenic strains has increased concerns about H7N9 pandemics. To develop an efficacious H7N9 human vaccine, we designed vaccine viruses by changing the patterns of N-linked glycosylation (NLG) on the viral hemagglutinin (HA) protein based on evolutionary patterns of H7 HA NLG changes. Notably, a virus in which 2 NLG modifications were added to HA showed higher growth rates in cell culture and elicited more cross-reactive antibodies than did other vaccine viruses with no change in the viral antigenicity. Developed into an inactivated vaccine formulation, the vaccine virus with 2 HA NLG additions exhibited much better protective efficacy against lethal viral challenge in mice than did a vaccine candidate with wild-type (WT) HA by reducing viral replication in the lungs. In a ferret model, the 2 NLG-added vaccine viruses also induced hemagglutination-inhibiting antibodies and significantly suppressed viral replication in the upper and lower respiratory tracts compared with the WT HA vaccines. In a mode of action study, the HA NLG modification appeared to increase HA protein contents incorporated into viral particles, which would be successfully translated to improve vaccine efficacy. These results suggest the strong potential of HA NLG modifications in designing avian influenza vaccines.

Association between regular physical activity and lower incidence of colorectal cancer in patients with diabetes mellitus: a nationwide cohort study.

AIM: The aim of this work was to investigate the association between changes in physical activity (PA) status and the development of colorectal cancer (CRC) in patients with diabetes. METHOD: This nationwide population study included 1 439 152 patients with diabetes who underwent a health screening provided by the Korean National Health Insurance Service between January 2009 and December 2012 and a follow-up screening after 2 years. Based on changes in PA status, participants were categorized into four groups: remained inactive, remained active, active-to-inactive and inactive-to-active. RESULTS: During the median follow-up period of 5.2 years, 38 244 new cases of CRC were diagnosed. Compared with the remained inactive group, among the three other groups, the remained active group had the lowest risk of CRC [adjusted hazard ratio (aHR) 0.93; 95% CI 0.90-0.96], followed by the inactive-to-active group (aHR 0.97; 95% CI 0.94-1.00) and active-to-inactive group (aHR 0.99; 95% CI 0.96-1.02), after adjusting for confounding variables (p = 0.0007). This reduction in cancer incidence in the remained active group was observed for both rectal cancer (aHR 0.87, 95% CI 0.79-0.95) and colon cancer (aHR 0.93, 95% CI 0.90-0.97), irrespective of sex. In terms of the intensity and amount of PA, moderate intensity PA was the most effective, and a positive correlation was found between the amount of PA and the reduction in CRC incidence. CONCLUSION: Regular PA was independently associated with a decreased risk of CRC in patients with diabetes. The intensity and amount of physical activity both play a role in reducing the risk.

Molecular Detection of Parvovirus in Manchurian Chipmunks (Tamias sibiricus asiaticus) Captured in Korea.

Cross-species transmission of viral diseases alarms our global community for its potential of novel pandemic events. Of various viral pathogens noted recently, parvoviruses have posed public health threats not only to humans but also to wild animals. To investigate the prevalence of parvoviruses in wild Manchurian chipmunks, here we detected genetic fragments of the nonstructural protein of parvovirus by polymerase chain reaction in wild Manchurian chipmunk specimens captured in the central and southern regions of South Korea and compared their sequence homology with references. Of a total of 348 specimens examined, chipmunk parvovirus (ChpPV)-specific gene fragments were detected with a 31.32% rate (109 chipmunks of 348) in their kidney, liver, lung, and spleen samples, and the chipmunks captured in Gangwon Province exhibited the highest positive rate (45.37%), followed by Gyeongsang (35.29%), Gyeonggi (31.03%), Chungcheong (20.00%), and Jeolla (19.70%). When compared with the reference sequences, a partial ChpPV sequence showed 97.70% identity to the previously reported Korean strain at the nucleic acid level. In the phylogenetic analysis, ChpPV exhibited closer relationship to primate parvoviruses, erythroviruses, and bovine parvovirus than to adeno-associated viruses. Despite limited sample size and genetic sequences examined in this study, our results underline the prevalence of ChpPV in Korea and emphasize the need of close surveillance of parvoviruses in wild animals.

Consistency of Helicobacter pylori eradication rates of first-line concomitant and sequential therapies in Korea: A nationwide multicenter retrospective study for the last 10 years.

BACKGROUND: Eradication rate of standard triple therapy for H. pylori has declined to unacceptable level, and alternative regimens such as concomitant and sequential therapy have been introduced. We aimed to assess the consistency of eradication rates of concomitant and sequential therapies as for the first-line H. pylori eradication in Korea. METHODS: A nationwide multicenter retrospective study was conducted including 18 medical centers from January 2008 to December 2017. We included 3,800 adults who had test to confirm H. pylori eradication within 1 year after concomitant or sequential therapy. RESULTS: Concomitant and sequential therapy were prescribed for 2508 and 1292 patients, respectively. The overall eradication rate of concomitant therapy was significantly higher than that of sequential therapy (91.8% vs. 86.1%, p < .001). In time trend analysis, the eradication rates of concomitant therapy were 90.2%, 88.2%, 92.1%, 94.3%, 91.1%, and 93.4% for each year from 2012 to 2017 with an increasing trend (p = .0146), while those of ST showed no significant trend (p = .0873). Among 263 patients with second-line therapy, bismuth quadruple therapy showed significantly higher eradication rate than quinolone-based triple therapy (73.9% vs. 51.5% in ITT analysis, p = .001; 82.7% vs. 63.0% in PP analysis, p = .002). CONCLUSION: Concomitant therapy is the best regimen for the first-line H. pylori eradication showing consistently higher eradication rate with an increasing trend for the last 10 years in Korea. Bismuth quadruple therapy should be considered for second-line therapy after eradication failure using non-bismuth quadruple therapy.

Convolutional neural network-based object detection model to identify gastrointestinal stromal tumors in endoscopic ultrasound images.

BACKGROUND AND AIM: We aimed to develop a convolutional neural network (CNN)-based object detection model for the discrimination of gastric subepithelial tumors, such as gastrointestinal stromal tumors (GISTs), and leiomyomas, in endoscopic ultrasound (EUS) images. METHODS: We used 376 images from 114 patients with histologically confirmed gastric GIST or leiomyoma to train the EUS-CNN. We constructed the EUS-CNN using an EfficientNet CNN model for feature extraction and a weighted bi-directional feature pyramid network for object detection. We assessed the performance of our EUS-CNN by calculating its accuracy, sensitivity, specificity, and area under receiver operating characteristic curve (AUC) using a validation set of 170 images from 54 patients. Four EUS experts and 15 EUS trainees were asked to judge the same validation dataset, and the diagnostic yields were compared between the EUS-CNN and human assessments. RESULTS: In the per-image analysis, the sensitivity, specificity, accuracy, and AUC of our EUS-CNN were 95.6%, 82.1%, 91.2%, and 0.9234, respectively. In the per-patient analysis, the sensitivity, specificity, accuracy, and AUC for our object detection model were 100.0%, 85.7%, 96.3%, and 0.9929, respectively. The EUS-CNN outperformed human assessment in terms of accuracy, sensitivity, and negative predictive value. CONCLUSIONS: We developed the EUS-CNN system, which demonstrated high diagnostic ability for gastric GIST prediction. This EUS-CNN system can be helpful not only for less-experienced endoscopists but also for experienced ones. Additional EUS image accumulation and prospective studies are required alongside validation in a large multicenter trial.

Novel Small Molecule Targeting the Hemagglutinin Stalk of Influenza Viruses.

Combating influenza is one of the perennial global public health issues to be managed. Antiviral drugs are useful for the treatment of influenza in the absence of an appropriate vaccine. However, the appearance of resistant strains necessitates a constant search for new drugs. In this study, we investigated novel anti-influenza drug candidates using in vitro and in vivo assays. We identified anti-influenza hit compounds using a high-throughput screening method with a green fluorescent protein-tagged recombinant influenza virus. Through subsequent analyses of their cytotoxicity and pharmacokinetic properties, one candidate (IY7640) was selected for further evaluation. In a replication kinetics analysis, IY7640 showed greater inhibitory effects during the early phase of viral infection than the viral neuraminidase inhibitor oseltamivir. In addition, we observed that hemagglutinin (HA)-mediated membrane fusion was inhibited by IY7640 treatment, indicating that the HA stalk region, which is highly conserved across various (sub)types of influenza viruses, may be the molecular target of IY7640. In an escape mutant analysis in cells, amino acid mutations were identified at the HA stalk region of the 2009 pandemic H1N1 (pH1N1) virus. Even though the in vivo efficacy of IY7640 did not reach complete protection in a lethal challenge study in mice, these results suggest that IY7640 has potential to be developed as a new type of anti-influenza drug.IMPORTANCE Anti-influenza drugs with broad-spectrum efficacy against antigenically diverse influenza viruses can be highly useful when no vaccines are available. To develop new anti-influenza drugs, we screened a number of small molecules and identified a strong candidate, IY7640. When added at the time of or after influenza virus infection, IY7640 was observed to successfully inhibit or reduce viral replication in cells. We subsequently discovered that IY7640 targets the stalk region of the influenza HA protein, which exhibits a relatively high degree of amino acid sequence conservation across various (sub)types of influenza viruses. Furthermore, IY7640 was observed to block HA-mediated membrane fusion of H1N1, H3N2, and influenza B viruses in cells. Although it appears less effective against strains other than H1N1 subtype viruses in a challenge study in mice, we suggest that the small molecule IY7640 has potential to be optimized as a new anti-influenza drug.

Sino-Cutaneous Fistula After Using Medpor Implant in Orbital Blowout Fracture.

In surgical repair of orbital fracture, implant materials play an important role in restoring the functional and anatomic structure of the orbit. Alloplastic implant materials are widely used for this surgery, but they have the risk of complications such as infections, pain, and extrusion. Because they are artificial implants, infection can occur more than autologous implants and is the most challenging problem to manage. Sino-cutaneous fistula is a rare complication of chronic sinusitis and it can be caused by this implant materials. The authors report a case of formation of sino-cutaneous fistula after using Medpor (Stryker Co, MI) implant in orbital blowout fracture repair.

Omega-3 Fatty Acid-Type Docosahexaenoic Acid Protects against Aß-Mediated Mitochondrial Deficits and Pathomechanisms in Alzheimer's Disease-Related Animal Model.

It has been reported that damage to the mitochondria affects the progression of Alzheimer's disease (AD), and that mitochondrial dysfunction is improved by omega-3. However, no animal or cell model studies have confirmed whether omega-3 inhibits AD pathology related to mitochondria deficits. In this study, we aimed to (1) identify mitigating effects of endogenous omega-3 on mitochondrial deficits and AD pathology induced by amyloid beta (Aß) in fat-1 mice, a transgenic omega-3 polyunsaturated fatty acids (PUFAs)-producing animal; (2) identify if docosahexaenoic acid (DHA) improves mitochondrial deficits induced by Aß in HT22 cells; and (3) verify improvement effects of DHA administration on mitochondrial deficits and AD pathology in B6SJL-Tg(APPSwFlLon,PSEN1*M146L*L286V)6799Vas/Mmjax (5XFAD), a transgenic Aß-overexpressing model. We found that omega-3 PUFAs significantly improved Aß-induced mitochondrial pathology in fat-1 mice. In addition, our in vitro and in vivo findings demonstrate that DHA attenuated AD-associated pathologies, such as mitochondrial impairment, Aß accumulation, neuroinflammation, neuronal loss, and impairment of adult hippocampal neurogenesis.

A Single Amino Acid in the Polymerase Acidic Protein Determines the Pathogenicity of Influenza B Viruses.

Influenza B virus (IBV) is one of the human respiratory viruses and one of the targets of seasonal vaccination. However, the bifurcation of two antigenically distinct lineages of IBVs makes it difficult to arrange proper medical countermeasures. Moreover, compared with pathogenicity-related molecular markers known for influenza A virus, little has been known for IBVs. To understand pathogenicity caused by IBVs, we investigated the molecular determinants of IBV pathogenicity in animal models. After serial lung-to-lung passages of Victoria lineage B/Brisbane/60/2008 (Vc_BR60) and Yamagata lineage B/Wisconsin/01/2010 (Ym_WI01) viruses in BALB/c mice, we identified the mouse-adapted Vc_BR60 (maVc_BR60) and Ym_WI01 (maYm_WI01) viruses, respectively. To find a molecular clue(s) to the increased pathogenicity of maVc_BR60 and maYm_WI01, we determined their genetic sequences. Several amino acid mutations were identified in the PB2, PB1, PA, BM2, and/or NS1 protein-coding regions, and one concurrent lysine (K)-to-arginine (R) mutation in PA residue 338 (PA K338R) was found in both maVc_BR60 and maYm_WI01 viruses. When analyzed using viruses rescued through reverse genetics, it was shown that PA K338R alone could increase the pathogenicity of both IBVs in mice and viral replication in the respiratory tracts of ferrets. In a subsequent minireplicon assay, the effect of PA K338R was highlighted by the enhancement of viral polymerase complex activity of both Vc_BR60 and Ym_WI01 viruses. These results suggest that the PA K338R mutation may be a molecular determinant of IBV pathogenicity via modulating the viral polymerase function of IBVs.IMPORTANCE To investigate molecular pathogenic determinants of IBVs, which are one of the targets of seasonal influenza vaccines, we adapted both Victoria and Yamagata lineage IBVs independently in mice. The recovered mouse-adapted viruses exhibited increased virulence, and of the various mutations identified from both mouse-adapted viruses, a concurrent amino acid mutation was found in the PA protein-coding region. When analyzed using viruses rescued through reverse genetics, the PA mutation alone appeared to contribute to viral pathogenicity in mice within the compatible genetic constellation between the IBV lineages and to the replication of IBVs in ferrets. Regarding the potential mechanism of increased viral pathogenicity, it was shown that the PA mutation could upregulate the viral polymerase complex activity of both IBV lineages. These results indicate that the PA mutation could be a newly defined molecular pathogenic determinant of IBVs that substantiates our understanding of the viral pathogenicity and public health risks of IBVs.

Distinct molecular evolution of influenza H3N2 strains in the 2016/17 season and its implications for vaccine effectiveness.

Influenza virus is a respiratory pathogen that causes seasonal epidemics by resulting in a considerable number of influenza-like illness (ILI) patients. During the 2016/17 season, ILI rates increased unusually earlier and higher than previous seasons in Korea, and most viral isolates were subtyped as H3N2 strains. Notably, the hemagglutinin (HA) of most Korean H3N2 strains retained newly introduced lysine signatures in HA antigenic sites A and D, compared with that of clade 3C.2a vaccine virus, which affected antigenic distances to the standard vaccine antisera in a hemagglutination inhibition assay. The neuraminidase (NA) of Korean H3N2 strains also harbored amino acid mutations. However, neither consistent amino acid mutations nor common phylogenetic clustering patterns were observed. These suggest that Korean H3N2 strains of the 2016/17 season might be distantly related with the vaccine virus both in genotypic and phenotypic classifications, which would adversely affect vaccine effectiveness.

One-step multiplex real-time RT-PCR for detection and typing of dengue virus.

Previous studies reported that severity of dengue is associated with multiple factors, including secondary infection, age, viral load and infecting serotype and genotype. In addition, other studies have reported that a dengue virus-2 (DENV-2) infection is associated with a prognosis of more severe clinical manifestations than DENV-1 and DENV-4 infections. For these reasons, the ability to identify the DENV serotypes is critical for optimal patient diagnosis and epidemiological studies. In this study, we developed a TaqMan probe-based, one-step real-time reverse transcriptase-polymerase chain reaction (RT-PCR) system for detection and serotyping DENV. Our linear dynamic range (101 to 107 copies/reaction) showed the R2 values of DENV-1, 2, 3 and 4 as 0.998, 0.998, 0.994, and 0.998, respectively. The detection limits of DENV-1, 2, 3, and 4, were 10 copies/reaction, 100 copies/reaction, 10 copies/reaction, and 100 copies/reaction, respectively. Specificity test results indicated that this system is specific for DENV-1, 2, 3, and 4 and does not react with other viruses. Finally, we validated our results with five different real-time PCR instruments. Our results showed that the Ct values of the four serotype templates were similar in five real-time PCR instruments. Thus, this system provides an accurate method for detection and serotyping of DENV, which can be applied in diagnostics, surveillance, and epidemiology. Dengue can be found in many nations with varying socioeconomic and monetary resources. The results of our validation analyses using five different real-time PCR instruments suggest that this method can easily and confidently be used world-wide.

Vitamin D-binding protein-loaded PLGA nanoparticles suppress Alzheimer's disease-related pathology in 5XFAD mice.

The aggregation and accumulation of amyloid beta (Aß) peptide is believed to be the primary cause of Alzheimer's disease (AD) pathogenesis. Vitamin D-binding protein (DBP) can attenuate Aß aggregation and accumulation. A biocompatible polymer poly (D,L-lactic acid-co-glycolic acid) (PLGA) can be loaded with therapeutic agents and control the rate of their release. In the present study, a PLGA-based drug delivery system was used to examine the therapeutic effects of DBP-PLGA nanoparticles in Aß-overexpressing (5XFAD) mice. DBP was loaded into PLGA nanoparticles and the characteristics of the DBP-PLGA nanoparticles were analyzed. Using a thioflavin-T assay, we observed that DBP-PLGA nanoparticles significantly inhibited Aß aggregation in vitro. In addition, we found that intravenous injection of DBP-PLGA nanoparticles significantly attenuated the Aß accumulation, neuroinflammation, neuronal loss and cognitive dysfunction in the 5XFAD mice. Collectively, our results suggest that DBP-PLGA nanoparticles could be a promising therapeutic candidate for the treatment of AD.

Pharmacological Stimulation of Nurr1 Promotes Cell Cycle Progression in Adult Hippocampal Neural Stem Cells.

Nuclear receptor related-1 (Nurr1) protein performs a crucial role in hippocampal neural stem cell (hNSC) development as well as cognitive functions. We previously demonstrated that the pharmacological stimulation of Nurr1 by amodiaquine (AQ) promotes spatial memory by enhancing adult hippocampal neurogenesis. However, the role of Nurr1 in the cell cycle regulation of the adult hippocampus has not been investigated. This study aimed to examine changes in the cell cycle-related molecules involved in adult hippocampal neurogenesis induced by Nurr1 pharmacological stimulation. Fluorescence-activated cell sorting (FACS) analysis showed that AQ improved the progression of cell cycle from G0/G1 to S phase in a dose-dependent manner, and MEK1 or PI3K inhibitors attenuated this progression. In addition, AQ treatment increased the expression of cell proliferation markers MCM5 and PCNA, and transcription factor E2F1. Furthermore, pharmacological stimulation of Nurr1 by AQ increased the expression levels of positive cell cycle regulators such as cyclin A and cyclin-dependent kinases (CDK) 2. In contrast, levels of CDK inhibitors p27KIP1 and p57KIP2 were reduced upon treatment with AQ. Similar to the in vitro results, RT-qPCR analysis of AQ-administered mice brains revealed an increase in the levels of markers of cell cycle progression, PCNA, MCM5, and Cdc25a. Finally, AQ administration resulted in decreased p27KIP1 and increased CDK2 levels in the dentate gyrus of the mouse hippocampus, as quantified immunohistochemically. Our results demonstrate that the pharmacological stimulation of Nurr1 in adult hNSCs by AQ promotes the cell cycle by modulating cell cycle-related molecules.

Red Ginseng Attenuates Aß-Induced Mitochondrial Dysfunction and Aß-mediated Pathology in an Animal Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disease and is characterized by neurodegeneration and cognitive deficits. Amyloid beta (Aß) peptide is known to be a major cause of AD pathogenesis. However, recent studies have clarified that mitochondrial deficiency is also a mediator or trigger for AD development. Interestingly, red ginseng (RG) has been demonstrated to have beneficial effects on AD pathology. However, there is no evidence showing whether RG extract (RGE) can inhibit the mitochondrial deficit-mediated pathology in the experimental models of AD. The effects of RGE on Aß-mediated mitochondrial deficiency were investigated in both HT22 mouse hippocampal neuronal cells and the brains of 5XFAD Aß-overexpressing transgenic mice. To examine whether RGE can affect mitochondria-related pathology, we used immunohistostaining to study the effects of RGE on Aß accumulation, neuroinflammation, neurodegeneration, and impaired adult hippocampal neurogenesis in hippocampal formation of 5XFAD mice. In vitro and in vivo findings indicated that RGE significantly improves Aß-induced mitochondrial pathology. In addition, RGE significantly ameliorated AD-related pathology, such as Aß deposition, gliosis, and neuronal loss, and deficits in adult hippocampal neurogenesis in brains with AD. Our results suggest that RGE may be a mitochondria-targeting agent for the treatment of AD.