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Kwon SY, Seo G, Jang M, Shin H, Choi W, Lim YB, Shin MS, Kim BN. The Effect of Mobile Neurofeedback Training in Children with Attention Deficit Hyperactivity Disorder: A Randomized Controlled Trial. Clin Psychopharmacol Neurosci 2024; 22:67-78. [PMID: 38247413 PMCID: PMC10811401 DOI: 10.9758/cpn.23.1054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/24/2023] [Accepted: 03/25/2023] [Indexed: 01/23/2024]
Abstract
Objective : To examine the effect of mobile neurofeedback training on the clinical symptoms, attention abilities, and execution functions of children with attention deficit hyperactivity disorder (ADHD). Methods : The participants were 74 children with ADHD aged 8-15 years who visited the Department of Child and Adolescent Psychiatry at Seoul National University Children's Hospital. The participants were randomly assigned to the mobile neurofeedback (n = 35) or control (sham; n = 39) group. Neurofeedback training was administered using a mobile app (equipped with a headset with a 2-channel electroencephalogram [EEG] sensor) for 30 min/day, 3 days/week, for 3 months. Children with ADHD were individually administered various neuropsychological tests, including the continuous performance test, Children's Color Trails Test-1 and 2, and Stroop Color and Word Tests. The effects of mobile neurofeedback were evaluated at baseline and at 3 and 6 months after treatment initiation. Results : Following treatment, both mobile neurofeedback-only and sham-only groups showed significant improvements in attention and response inhibition. In the visual continuous performance test, omission errors decreased to the normal range in the mobile neurofeedback-only group after training, suggesting that mobile neurofeedback effectively reduced inattention in children with ADHD. In the advanced test of attention, auditory response times decreased in the mobile neurofeedback + medication group after training, but increased in the sham+medication group. Overall, there were no significant between-group differences in other performance outcomes. Conclusion : Mobile neurofeedback may have potential as an additional therapeutic option alongside medication for children with ADHD.
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Affiliation(s)
- Seo Young Kwon
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Gyujin Seo
- Biomedical Research Institute, Seoul National University, Seoul, Korea
| | - Mirae Jang
- Biomedical Research Institute, Seoul National University, Seoul, Korea
| | - Hanbyul Shin
- Biomedical Research Institute, Seoul National University, Seoul, Korea
| | - Wooseok Choi
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - You Bin Lim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Min-Sup Shin
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Bung-Nyun Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
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Yang CM, Shin J, Kim JI, Lim YB, Park SH, Kim BN. Classifying Children with ADHD Based on Prefrontal Functional Near-infrared Spectroscopy Using Machine Learning. Clin Psychopharmacol Neurosci 2023; 21:693-700. [PMID: 37859442 PMCID: PMC10591175 DOI: 10.9758/cpn.22.1025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 10/21/2023]
Abstract
Objective : Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in children and adults characterized by cognitive and emotional self-control deficiencies. Previous functional near-infrared spectroscopy (fNIRS) studies found significant group differences between ADHD children and healthy controls during cognitive flexibility tasks in several brain regions. This study aims to apply a machine learning approach to identify medication-naive ADHD patients and healthy control (HC) groups using task-based fNIRS data. Methods : fNIRS signals from 33 ADHD children and 39 HC during the Stroop task were analyzed. In addition, regularized linear discriminant analysis (RLDA) was used to identify ADHD individuals from healthy controls, and classification performance was evaluated. Results : We found that participants can be correctly classified in RLDA leave-one-out cross validation, with a sensitivity of 0.67, specificity of 0.93, and accuracy of 0.82. Conclusion : RLDA using only fNIRS data can effectively discriminate children with ADHD from HC. This study suggests the potential utility of the fNIRS signal as a diagnostic biomarker for ADHD children.
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Affiliation(s)
- Chan-Mo Yang
- Department of Psychiatry, Wonkwang University School of Medicine, Iksan, Korea
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Jaeyoung Shin
- Department of Electronic Engineering, Wonkwang University, Iksan, Korea
| | | | - You Bin Lim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - So Hyun Park
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Bung-Nyun Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
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Do R, Kim S, Lim YB, Kim SJ, Kwon H, Kim JM, Lee S, Kim BN. Korean adolescents' coping strategies on self-harm, ADHD, insomnia during COVID-19: text mining of social media big data. Front Psychiatry 2023; 14:1192123. [PMID: 38034911 PMCID: PMC10686066 DOI: 10.3389/fpsyt.2023.1192123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 10/31/2023] [Indexed: 12/02/2023] Open
Abstract
Introduction Since the Coronavirus disease 2019 (COVID-19), public safety measures, including social distancing and school closures, have been implemented, precipitating psychological difficulties and heightened online activities for adolescents. However, studies examining the impact of the pandemic on adolescent mental health and their coping strategies in Asian countries are limited. Further, most studies have used survey measures to capture mental health challenges so far. Accordingly, this study aimed to examine the psychological challenges South Korean adolescents experienced and their coping strategies during the pandemic using the Natural Language Processing (NLP) and Text mining (TM) technique on adolescents' social media texts/posts. Methods The data were gathered from social media texts/posts such as online communities, Twitter, and personal blogs from January 1, 2019, to October 31, 2021. The 12,520,250 texts containing keywords related to adolescents' common psychological difficulties reported during the pandemic, including self-harm, Attention-Deficit/Hyperactivity Disorders (ADHD), and insomnia, were analyzed by TM, NLP using information extraction, co-occurrence and sentiment analysis. The monthly frequency of the keywords and their associated words was also analyzed to understand the time trend. Results Adolescents used the word "self-harm" in their social media texts more frequently during the second wave of COVID-19 (August to September 2020). "Friends" was the most associated word with "self-harm." While the frequency of texts with "Insomnia" stayed constant throughout the pandemic, the word "ADHD" was increasingly mentioned in social media. ADHD and insomnia were most frequently associated with ADHD medications and sleeping pills, respectively. Friends were generally associated with positive words, while parents were associated with negative words. Conclusion During COVID-19, Korean adolescents often expressed their psychological challenges on social media platforms. However, their coping strategies seemed less efficient to help with their difficulties, warranting strategies to support them in the prolonged pandemic era. For example, Korean adolescents shared psychological challenges such as self-harm with friends rather than their parents. They considered using medicine (e.g., sleeping pills and ADHD medication) as coping strategies for sleep and attention problems.
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Affiliation(s)
- Ryemi Do
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Soyeon Kim
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
- Waypoint Research Institute, Waypoint Centre for Mental Health Care, Penetanguishene, ON, Canada
| | - You Bin Lim
- Division of Child and Adolescent Psychiatry, Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Su-Jin Kim
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hyerim Kwon
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | | | - Sooyeon Lee
- Division of Child and Adolescent Psychiatry, Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Bung-Nyun Kim
- Division of Child and Adolescent Psychiatry, Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
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Choi W, Hong SB, Kim JI, Lee J, Jang S, Ahn YD, Lim YB, Kim S, Oh MR, Kim BN. Association of Pre- and Perinatal Risk Factors With Tourette Syndrome or Chronic Tic Disorders in a Korean School-Age Population. Soa Chongsonyon Chongsin Uihak 2023; 34:37-44. [PMID: 36636494 PMCID: PMC9816007 DOI: 10.5765/jkacap.220024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 01/05/2023] Open
Abstract
Objectives Tic disorders are highly heritable; however, growing evidence suggests that environmental factors play a significant role in their pathogenesis. Studies on these factors have been inconsistent, with conflicting results. Therefore, this study aimed to examine the associations of pre- and perinatal exposure to Tourette syndrome (TS) or chronic tic disorders (CTD) in Korean school-aged children. Methods This case-control study used data from a large prospective cohort study. The primary outcome was TS/CTD diagnosis according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) criteria and Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version-Korean Version. Demographic, pre-, and perinatal information was obtained from the maternal questionnaires. Data between the TS/CTD and control groups were compared using the chi-squared or Student's t-test, as appropriate. Two-step logistic regression analyses were used to test the association between TS/CTD and pre- and perinatal risk factors. Results We included of 223 children (78 with TS/CTD and 145 controls). Significant differences in the demographic data between the two groups were observed. The male sex ratio, mean parental age, parental final education level, and family history of tics were included as confounders. In the final adjusted multivariable model, TS/CTD was significantly associated with antiemetic exposure during pregnancy (odds ratio [OR]=16.61, 95% confidence interval [CI] 1.49-185.22, p=0.02) and medically assisted reproduction (OR=7.89, 95% CI 2.28-27.28, p=0.01). Conclusion Antiemetic exposure and medically assisted reproduction are significantly associated with the risk of TS/CTD. These results should be replicated in future prospective and gene-by-environment studies.
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Affiliation(s)
- Wooseok Choi
- Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Soon-beom Hong
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | | | - Jung Lee
- Integrative Care Hub, Children’s Hospital, Seoul National University Hospital, Seoul, Korea
| | - Soomin Jang
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Yebin D Ahn
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - You Bin Lim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Sumin Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Mee Rim Oh
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea
| | - Bung-Nyun Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, Seoul, Korea,Address for correspondence: Bung-Nyun Kim, Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea Tel: +82-2-2072-3647, Fax: +82-2-747-2471, E-mail:
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Lim YB, Kweon K, Kim BN. Effects of Adversities during Childhood on Anxiety Symptoms in Children and Adolescents: Comparison of Typically Developing Children and Attention-Deficit/ Hyperactivity Disorder Group. Soa Chongsonyon Chongsin Uihak 2021; 32:118-125. [PMID: 34285637 PMCID: PMC8262970 DOI: 10.5765/jkacap.210003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/05/2021] [Accepted: 05/07/2021] [Indexed: 11/20/2022] Open
Abstract
Objectives Childhood adversity is a risk factor for anxiety symptoms, but it affects anxiety symptoms in attention-deficit/hyperactivity disorder (ADHD). The current study aimed to examine the association between childhood adversity and anxiety symptoms in participants with and without ADHD. Methods Data were obtained from a school-based epidemiological study of 1017 randomly selected children and adolescents. The ADHD and non-ADHD groups were divided using the Diagnostic Interview Schedule for Children Predictive Scale (DPS). The DPS was also used to assess comorbidities such as anxiety and mood disorders. The childhood adversities were assessed using the Early Trauma Inventory Self Report-Short Form, and the anxiety symptoms were assessed using the Screen for Child Anxiety Related Disorders. Linear and logistic regression models were used to investigate the association between childhood adversity and anxiety in the ADHD and non-ADHD groups with adjustments for age and sex. Results This study found that the ADHD group did not show any significant association between anxiety symptoms and childhood adversities, whereas the non-ADHD group always showed a significant association. In a subgroup analysis of the non-ADHD group, the normal group without any psychiatric disorders assessed with DPS demonstrated a statistically significant association between childhood adversities and anxiety symptoms. These results were consistent with the association between childhood adversities and anxiety disorders assessed using DPS, as shown by logistic regression. Conclusion The association between anxiety symptoms and childhood adversities statistically disappears in ADHD; ADHD may mask or block the association. Further longitudinal research is necessary to investigate this relationship.
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Affiliation(s)
- You Bin Lim
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea
| | - Kukju Kweon
- Department of Psychiatry, School of Medicine and Institute of Brain Research, Chungnam National University, Daejeon, Korea
| | - Bung-Nyun Kim
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea.,Division of Child and Adolescent Psychiatry, Department of Neuropsychiatry, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea
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Lim YB, Kim JW, Hong SB, Kim JW. Association between BDNF and Antidepressant Effects of Exercise in Youth: A Preliminary Study. Soa Chongsonyon Chongsin Uihak 2016. [DOI: 10.5765/jkacap.2016.27.1.72] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- You Bin Lim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Jun Won Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Soon-Beom Hong
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Jae-Won Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
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Abstract
RATIONALE Modulators of the ρ1 GABAA receptor may be useful in the treatment of visual, sleep, and cognitive disorders. Neuroactive steroids and analogues have been shown to modulate ρ1 receptor function, but the molecular mechanisms are poorly understood. OBJECTIVES We employed electrophysiology and voltage-clamp fluorometry to compare the actions of several neuroactive steroids and analogues on the human ρ1 GABAA receptor. RESULTS Results confirmed that P294S and T298F mutations affect modulation by steroids. The P294S mutation abolished inhibition by (3α,5β)-3-hydroxypregnan-20-one (3α5βP) while the T298F mutation eliminated inhibition by 17β-estradiol. Voltage-clamp fluorometry demonstrated that steroids differing in the presence of a charged group on C3 or nature of substituent on C17 uniquely modified fluorescence changes elicited by GABA in the extracellular domain. The I307Q mutation reversed the inhibitory effect of 3α5βP but was without effect on modulation by (3α,5β)-3-hydroxypregnan-20-one sulfate or 17β-estradiol. The effect of 3α5βP on the fluorescence change generated at Y241C was dependent on whether the steroid acted as an inhibitor or a potentiator. Further, the effect was limited to uncharged 5β-reduced steroids containing an acetyl group on C17. CONCLUSIONS The data demonstrate that steroids and analogues differ with respect to conformational changes elicited by these drugs as well as sensitivity to the effects of mutations. Steroids and analogues could be provisionally divided into three major groups based on their actions on the ρ1 GABAA receptor: 5β-reduced uncharged steroids, sulfated and carboxylated steroids, and 17β-estradiol. Further division among 5β-reduced uncharged steroids was based on substituent at position C17.
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Affiliation(s)
- Megan M Eaton
- Department of Anesthesiology, Washington University School of Medicine, Campus Box 8054, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
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Kim HW, Hwang KE, Song DH, Kim YJ, Lim YB, Choi JH, Choi YS, Kim HY, Kim CJ. Effects of soy sauce on physicochemical and textural properties of tumbled chicken breast. Poult Sci 2014; 93:680-6. [PMID: 24604862 DOI: 10.3382/ps.2012-02930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to evaluate the effects of soy sauce on the physicochemical and textural properties of tumbled chicken breasts. Chicken breasts marinated with distilled water (Con), 4% NaCl solution, 4% NaCl and lactic acid solution (pH 4.9), and soy sauce solution (4% salt concentration and pH 4.9) were vacuum tumbled at 3°C for 60 min. The chicken breast marinated with soy sauce solution showed lower lightness and higher redness and yellowness due to the color of the soy sauce. The acidic marinades led to a decrease in pH value of tumbled chicken breast. The acidic marinades increased collagen solubility of sample compared with 4% NaCl solution, resulting in decreased shear force. Water-holding capacity, marination and cooking yields, and solubility of myofibrillar proteins were mainly affected by the presence of salt in the marinade, rather than by pH alternation. Our results suggested that soy sauce marination can improve the tenderness of tumbled chicken breast.
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Affiliation(s)
- H W Kim
- Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 143-701, Republic of Korea
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Eaton MM, Lim YB, Bracamontes J, Steinbach JH, Akk G. Agonist-specific conformational changes in the α1-γ2 subunit interface of the GABA A receptor. Mol Pharmacol 2012; 82:255-63. [PMID: 22572883 DOI: 10.1124/mol.112.077875] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The GABA(A) receptor undergoes conformational changes upon the binding of agonist that lead to the opening of the channel gate and a flow of small anions across the cell membrane. Besides the transmitter GABA, allosteric ligands such as the general anesthetics pentobarbital and etomidate can activate the receptor. Here, we have investigated the agonist specificity of structural changes in the extracellular domain of the receptor. We used the substituted cysteine accessibility method and focused on the γ2(S195C) site (loop F). We show that modification of the site with (2-sulfonatoethyl)methanethiosulfonate (MTSES) results in an enhanced response to GABA, indicating accessibility of the resting receptor to the modifying agent. Coapplication of GABA or muscimol, but not of gabazine, with MTSES prevented the effect, suggesting that GABA and muscimol elicit a conformational change that reduces access to the γ2(S195C) site. Exposure of the receptors to MTSES in the presence of the allosteric activators pentobarbital and etomidate resulted in an enhanced current response indicating accessibility and labeling of the γ2(S195C) site. However, comparison of the rates of modification indicated that labeling in the presence of etomidate was significantly faster than that in the presence of pentobarbital or gabazine or in resting receptors. We infer from the data that the structure of the α1-γ2 subunit interface undergoes agonist-specific conformational changes.
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Affiliation(s)
- Megan M Eaton
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
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Shin HT, Baig SY, Lee SW, Suh DS, Kwon ST, Lim YB, Lee JH. Production of fructo-oligosaccharides from molasses by Aureobasidium pullulans cells. Bioresour Technol 2004; 93:59-62. [PMID: 14987721 DOI: 10.1016/j.biortech.2003.10.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2003] [Revised: 06/30/2003] [Accepted: 10/02/2003] [Indexed: 05/24/2023]
Abstract
Three different strains of Aureobasidium pullulans were grown in batch cultures to compare their abilities for the production of fructo-oligosaccharides. Specific intracellular enzyme activity was the highest with strain KCCM 12017 and enzyme production was closely coupled to growth. Using A. pullulans cells, 166 g/l fructo-oligosaccharides was produced from 360 g/l molasses sugar as sucrose equivalent at 55 degrees C and pH 5.5 after 24 h incubation.
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Affiliation(s)
- H T Shin
- Department of Food and Life Science, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon 440-746, South Korea
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Lim YB, Kang SS, Park TK, Lee YS, Chun JS, Sonn JK. Disruption of actin cytoskeleton induces chondrogenesis of mesenchymal cells by activating protein kinase C-alpha signaling. Biochem Biophys Res Commun 2000; 273:609-13. [PMID: 10873653 DOI: 10.1006/bbrc.2000.2987] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Disruption of actin cytoskeleton with cytochalasin D has been known to induce chondrogenic differentiation of chick embryo limb bud mesenchymal cells. However, the mechanism(s) for the induction of chondrogenesis by cytochalasin D is not yet clearly known. In the present study, we examined possible involvement of protein kinase C (PKC) and extracellular signal-regulated protein kinase (Erk-1) in chondrogenesis of mesenchymal cells induced by disruption of actin cytoskeleton. Disruption of actin cytoskeleton with cytochalasin D or latrunculin B induced chondrogenesis of mesenchymal cells cultured at subconfluent cell density, as determined by type II collagen expression. Among the expressed PKC isoforms, cytochalasin D dramatically increased expression and activation of PKCalpha in a dose-dependent manner, and inhibition or downregulation of PKCalpha blocked cytochalasin D-induced chondrogenesis. Cytochalasin D also downregulated Erk-1 phosphorylation that is associated with chondrogenesis. Our results, therefore, suggest that disruption of actin cytoskeleton induces chondrogenesis of mesenchymal cells by activating PKCalpha and by inhibiting Erk-1 signaling.
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Affiliation(s)
- Y B Lim
- Department of Biology, Teacher's College, Taegu, 702-701, Korea
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Lim YB, Han SO, Kong HU, Lee Y, Park JS, Jeong B, Kim SW. Biodegradable polyester, poly[alpha-(4-aminobutyl)-L-glycolic acid], as a non-toxic gene carrier. Pharm Res 2000; 17:811-6. [PMID: 10990199 DOI: 10.1023/a:1007552007765] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The aim of this study was to develop a non-toxic polymeric gene carrier. For this purpose, biodegradable cationic polymer, poly[alpha-(4-aminobutyl)-L-glycolic acid] (PAGA) was synthesized. PAGA was designed to have ester linkage because polyesters usually show biodegradability. METHODS Degradation of PAGA in an aqueous solution was followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). PAGA/DNA complexes were characterized by gel electrophoresis, atomic force microscopy (AFM), dynamic light scattering (DLS). The transfection was measured by using the beta-galactosidase reporter gene. RESULTS PAGA was degraded in aqueous solution very quickly and the final degradation product was a monomer (L-oxylysine). Formation of self-assembling biodegradable complexes between PAGA and DNA at a charge ratio 1:1 (+/-) was confirmed by gel band shift assay and AFM. In these studies, controlled release of DNA from the complexes could be seen. The complexes showed about 2-fold higher transfection efficiency than DNA complexes of poly-L-lysine (PLL), a structural analogue of PAGA, which is the most commonly used poly-cation for gene delivery. The polymer did not show cytotoxicity, possibly because of its degradability and the biocompatibility of the monomer. CONCLUSIONS The use of the biodegradable poly-cation, PAGA, as a DNA condensing agent will be useful in safe gene delivery.
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Affiliation(s)
- Y B Lim
- School of Chemistry & Molecular Engineering, Seoul National University, Korea
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