Publications by authors named "Juhyung Lee"

28 Publications

  • Page 1 of 1

Variable host responses mediate host preference in marine flatworm-snail symbioses.

PLoS One 2021 2;16(3):e0247551. Epub 2021 Mar 2.

Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama.

Host preference of symbionts evolves from fitness trade-offs. However, it is often unclear how interspecific variations in host response traits influence this evolutionary process. Using the association between the polyclad flatworm Paraprostatum echinolittorinae and its intertidal snail hosts on the Pacific Coast of Panama, we assessed how a symbiont's host preference is associated with varying host defenses and post-infestation performances. We first characterized the prevalence and intensity of worm infestation in five snail hosts (Tegula pellisserpentis, Nerita scabricosta, N. funiculata, Planaxis planicostatus, and Cerithium stercusmuscarum). We then used manipulative experiments to test flatworm's host choice, hosts' behavioral rejection of flatworms, and hosts' growth and survival following the infestation. In the field, flatworms were orders of magnitude more prevalent and dense in T. pellisserpentis, N. scabricosta, N. funiculata than P. planicostatus and C. stercusmuscarum, although the three former hosts were not necessarily more abundant. The results from our laboratory host selection trials mirrored these patterns; flatworms were 3 to 14 times more likely to choose T. pellisserpentis, N. scabricosta, N. funiculata over P. planicostatus and C. stercusmuscarum. The less preferred hosts frequently rejected flatworms via mantle contractions and foot withdrawals, which reduced the infestation rate by 39%-67%. These behaviors were less frequent or absent in the preferred hosts. Flatworm infestation variably influenced host performances in the field, negligibly affecting the growth and survival of T. pellisserpentis and N. funiculata but reducing the growth of P. planicostatus. Flatworms thus preferred less defended hosts that can also support higher worm densities without being harmed. Stable isotope analysis further revealed that flatworms are unlikely to feed on snail tissues and may live as a commensal in their preferred hosts. Our study demonstrates that host response traits can modulate a symbiont's host choice and calls for more explicit considerations of host response variability in host preference research.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247551PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7924752PMC
March 2021

Physicians' Awareness of the Breast Cancer Survivors' Unmet Needs in Korea.

J Breast Cancer 2021 Feb;24(1):85-96

Department of Surgery, Research Institute of Clinical Medicine, Jeonbuk National University Hospital, Jeonbuk National University and Biomedical Research Institute, Jeonju, Korea.

Purpose: Physicians' awareness of their cancer patients' unmet needs is an essential element for providing effective treatment. This study investigated the accuracy of physicians' awareness of breast cancer survivors' unmet needs in Korea.

Methods: A cross-sectional interview survey was performed among 106 physicians and 320 Korean breast cancer survivors. The Comprehensive Needs Assessment Tool was administered to physicians and cancer survivors after obtaining their written informed consent to participate. Data were analyzed using -test, analysis of variance, and multiple regression analysis.

Results: The level of unmet needs was highest in the hospital service domain (mean ± standard deviation: 2.19 ± 0.82), and the top-ranked unmet need item was "wished my doctor to be easy, specific, and honest in his/her explanation" (2.44 ± 0.93). Higher unmet needs were correlated with the presence of a genetic counseling clinic. They were not associated with age, sex, marital status, religion, department, working period, type of institution, number of staff, and number of operations. In multiple regression analysis, the presence of a genetic counseling clinic was associated with a higher level of recognition for psychological problems, social support, hospital service, and information and education needs. Physicians overestimated breast cancer survivors' unmet needs in all domains, compared to their self-reported unmet needs. The discordance in the perceived unmet needs was highest in the 'family/personal relationship problems' domain.

Conclusions: Physicians who treat Korean breast cancer survivors rated the level of unmet needs of breast cancer survivors as highest in the hospital service domain. The presence of a genetic counseling clinic in physicians' institutions was associated with a higher perception of survivors' unmet needs. Physicians overestimated the level of unmet needs in Korean breast cancer survivors. Efforts to reduce these discordances are needed to implement optimal survivorship care.
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http://dx.doi.org/10.4048/jbc.2021.24.e3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7920866PMC
February 2021

Effects of steroid therapy in patients with severe fever with Thrombocytopenia syndrome: A multicenter clinical cohort study.

PLoS Negl Trop Dis 2021 Feb 19;15(2):e0009128. Epub 2021 Feb 19.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an acute, febrile, and potentially fatal tick-borne disease caused by the SFTS Phlebovirus. Here, we evaluated the effects of steroid therapy in Korean patients with SFTS.

Methods: A retrospective study was performed in a multicenter SFTS clinical cohort from 13 Korean university hospitals between 2013 and 2017. We performed survival analysis using propensity score matching of 142 patients with SFTS diagnosed by genetic or antibody tests.

Results: Overall fatality rate was 23.2%, with 39.7% among 58 patients who underwent steroid therapy. Complications were observed in 37/58 (63.8%) and 25/83 (30.1%) patients in the steroid and non-steroid groups, respectively (P < .001). Survival analysis after propensity score matching showed a significant difference in mean 30-day survival time between the non-steroid and steroid groups in patients with a mild condition [Acute Physiology and Chronic Health Evaluation II (APACHE II) score <14; 29.2 (95% CI 27.70-30.73] vs. 24.9 (95% CI 21.21-28.53], P = .022]. Survival times for the early steroid (≤5 days from the start of therapy after symptom onset), late steroid (>5 days), and non-steroid groups, were 18.4, 22.4, and 27.3 days, respectively (P = .005).

Conclusions: After steroid therapy, an increase in complications was observed among patients with SFTS. Steroid therapy should be used with caution, considering the possible negative effects of steroid therapy within 5 days of symptom onset or in patients with mild disease (APACHE II score <14).
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http://dx.doi.org/10.1371/journal.pntd.0009128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928499PMC
February 2021

Heparan sulfate assists SARS-CoV-2 in cell entry and can be targeted by approved drugs in vitro.

Cell Discov 2020 Nov 4;6(1):80. Epub 2020 Nov 4.

Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.

The cell entry of SARS-CoV-2 has emerged as an attractive drug repurposing target for COVID-19. Here we combine genetics and chemical perturbation to demonstrate that ACE2-mediated entry of SARS-Cov and CoV-2 requires the cell surface heparan sulfate (HS) as an assisting cofactor: ablation of genes involved in HS biosynthesis or incubating cells with a HS mimetic both inhibit Spike-mediated viral entry. We show that heparin/HS binds to Spike directly, and facilitates the attachment of Spike-bearing viral particles to the cell surface to promote viral entry. We screened approved drugs and identified two classes of inhibitors that act via distinct mechanisms to target this entry pathway. Among the drugs characterized, Mitoxantrone is a potent HS inhibitor, while Sunitinib and BNTX disrupt the actin network to indirectly abrogate HS-assisted viral entry. We further show that drugs of the two classes can be combined to generate a synergized activity against SARS-CoV-2-induced cytopathic effect. Altogether, our study establishes HS as an attachment factor that assists SARS coronavirus cell entry and reveals drugs capable of targeting this important step in the viral life cycle.
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http://dx.doi.org/10.1038/s41421-020-00222-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7610239PMC
November 2020

Targeting heparan sulfate proteoglycan-assisted endocytosis as a COVID-19 therapeutic option.

bioRxiv 2020 Jul 14. Epub 2020 Jul 14.

Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.

Drugs capable of blocking the infectious cycle of the coronavirus SARS-CoV-2 are urgently needed to tackle the ongoing COVID-19 pandemic. To this end, the cell entry of SARS-CoV-2, initiated by the binding of the viral Spike (S) protein to human ACE2, has emerged as an attractive drug repurposing target. Here we use murine leukemia viruses pseudotyped with Spike from SARS-CoV or SARS-CoV-2 to demonstrate that ACE2-mediated coronavirus entry can be mitigated by heparin, a heparan sulfate-related glycan, or by genetic ablation of biosynthetic enzymes for the cell surface heparan sulfate proteoglycans (HSPGs). A drug repurposing screen targeting HSPG-dependent endocytosis identifies pharmacologically active endocytosis inhibitors that also abrogate coronavirus cell entry. Among them, Mitoxantrone (EC =~10 nM) targets HSPGs directly, whereas Sunitinib and BNTX disrupt the actin network to impair HSPG-assisted viral entry. Gene expression profiling suggests potential combination regimens that optimally target HSPG-dependent viral entry. Altogether, our study establishes HSPGs as an assisting factor for ACE2 in endocytosis-mediated coronavirus entry and identifies drugs that can be repurposed to target this important stage in the viral life cycle.
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http://dx.doi.org/10.1101/2020.07.14.202549DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7373127PMC
July 2020

Nanometer-Scale Vibration Measurement Using an Optical Quadrature Interferometer based on 3 × 3 Fiber-Optic Coupler.

Sensors (Basel) 2020 May 7;20(9). Epub 2020 May 7.

School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Korea.

We propose a nanometer-scale displacement or vibration measurement system, using an optical quadrature interferometer and the post-processing technique that extracts the parameters necessary for characterizing the interferometric system. Using a 3 × 3 fiber-optic coupler, the entire complex interference signal could be reconstructed with two interference signals measured at two return ports of the coupler. The intrinsic phase difference between the return ports was utilized to obtain the quadratic part of the interference signal, which allowed one to reconstruct the entire complex interference signal. However, the two measured signals were appreciably affected by the unequal detector gains and non-uniform intrinsic phases of the coupler. Fortunately, we could find that the Lissajous curve plotted by the two signals of the interferometric system would form an ellipse. Therefore, by fitting the measured Lissajous curve to an ellipse, we could extract the parameters characterizing the actual system, which allowed the nanometer-scale measurement. Experimental results showed that a 20 kHz sinusoidal vibration with an amplitude of 1.5 nm could be measured with a standard deviation of 0.4 nm.
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http://dx.doi.org/10.3390/s20092665DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7249211PMC
May 2020

A myosin-7B-dependent endocytosis pathway mediates cellular entry of α-synuclein fibrils and polycation-bearing cargos.

Proc Natl Acad Sci U S A 2020 05 4;117(20):10865-10875. Epub 2020 May 4.

Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892;

Cell-to-cell transmission of misfolding-prone α-synuclein (α-Syn) has emerged as a key pathological event in Parkinson's disease. This process is initiated when α-Syn-bearing fibrils enter cells via clathrin-mediated endocytosis, but the underlying mechanisms are unclear. Using a CRISPR-mediated knockout screen, we identify SLC35B2 and myosin-7B (MYO7B) as critical endocytosis regulators for α-Syn preformed fibrils (PFFs). We show that SLC35B2, as a key regulator of heparan sulfate proteoglycan (HSPG) biosynthesis, is essential for recruiting α-Syn PFFs to the cell surface because this process is mediated by interactions between negatively charged sugar moieties of HSPGs and clustered K-T-K motifs in α-Syn PFFs. By contrast, MYO7B regulates α-Syn PFF cell entry by maintaining a plasma membrane-associated actin network that controls membrane dynamics. Without MYO7B or actin filaments, many clathrin-coated pits fail to be severed from the membrane, causing accumulation of large clathrin-containing "scars" on the cell surface. Intriguingly, the requirement for MYO7B in endocytosis is restricted to α-Syn PFFs and other polycation-bearing cargos that enter cells via HSPGs. Thus, our study not only defines regulatory factors for α-Syn PFF endocytosis, but also reveals a previously unknown endocytosis mechanism for HSPG-binding cargos in general, which requires forces generated by MYO7B and actin filaments.
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http://dx.doi.org/10.1073/pnas.1918617117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245082PMC
May 2020

Risk of cerebro- and cardiovascular disease in patients with scrub typhus.

Eur J Clin Microbiol Infect Dis 2020 Mar 27;39(3):451-454. Epub 2019 Nov 27.

Department of Internal Medicine, Chonbuk National University, Jeonju, Republic of Korea.

We analyzed the National Health Insurance Service-National Sample Cohort (NHIS-NSC) data to evaluate whether scrub typhus infection is associated with increased risk of subsequent cardio- and cerebrovascular disease. Compared with the control group, the scrub typhus group showed a greater incidence rate of cardiovascular disease (14.5 vs. 9.0 cases per 1000 person-years). In contrast, the scrub typhus group showed no difference in incidence rate of cerebrovascular disease (12.0 vs. 13.3 cases per 1000 person-years). Based on the NHIS-NSC data, patients with scrub typhus are at greater risk of developing cardiovascular disease long term compared with that of the general population.
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http://dx.doi.org/10.1007/s10096-019-03743-4DOI Listing
March 2020

Altered Resting-State Functional Connectivity in Wernicke's Encephalopathy With Vestibular Impairment.

Front Neurol 2019 27;10:1035. Epub 2019 Sep 27.

Department of Neurology, Ludwig-Maximilians-University, Munich, Germany.

To reveal the neural basis of Wernicke's encephalopathy (WE) with impaired vestibulo-ocular reflex (VOR), we evaluated resting-state functional connectivity (rs-fc) in the vestibular processing brain regions. Rs-fc between the vestibular regions and the rest of the brain were compared with neurotological features including the head-impulse tests (vHIT) and caloric responses in patients with WE ( = 5, mean age 53.4 ± 10 years) and healthy controls ( = 20, mean age 55.0 ± 9.2 years). Rs-fc analyses employed a region of interest (ROI)-based approach using regions selected a priori that participate in vestibular processing including the cerebellar vermis, insula, parietal operculum, and calcarine cortex. The main neurologic findings for patients with WE were mental changes; gait ataxia; spontaneous and gaze-evoked nystagmus (GEN); and bilaterally positive HIT for the horizontal canals. Video HIT documented bilateral horizontal canal dysfunction with decreased gain and corrective saccades. Caloric irrigation and rotation chair testing revealed prominent bilateral horizontal canal paresis. Patients with WE also had decreased spatial memory, which substantially recovered after treatments. Functional connections at the predefined seed regions, including the insular cortex and parietal operculum, were attenuated in the WE group compared to healthy controls. WE is related to impaired VOR and visuospatial dysfunction, and fMRI documented changes in the rs-fc of multisensory vestibular processing regions including the insula, parietal operculum, and superior temporal gyrus, which participate in integration of vestibular perception.
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http://dx.doi.org/10.3389/fneur.2019.01035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6776602PMC
September 2019

Unmet needs and related factors of Korean breast cancer survivors: a multicenter, cross-sectional study.

BMC Cancer 2019 Aug 27;19(1):839. Epub 2019 Aug 27.

Department of Surgery, Research Institute of Clinical Medicine, Chonbuk National University Hospital, Chonbuk National University and Biomedical Research Institute, 20, Geonji-ro, Deokjin-gu, Jeonju-si, Jeollabuk-do, Korea.

Background: Identification of specific needs in patients with cancer is very important for the provision of patient-centered medical service. The aim of this study was to investigate the unmet needs and related factors of Korean breast cancer survivors.

Methods: A multicenter, cross-sectional, interview survey was performed among 332 Korean breast cancer survivors. The Comprehensive Needs Assessment Tool for cancer patients was administered to survivors who gave written informed consent to participate. Data were analyzed using t-test, ANOVA and multiple regression analysis.

Results: The level of unmet needs was highest in the domain 'Information and education' (mean ± SD; 1.70 ± 1.14) and the item with the highest level of unmet needs was 'Needed help in coping with fear of recurrence' (2.04 ± 1.09). Unmet needs were correlated with age, stage, multiplicity, HER2, treatment state, marital status, employment, psychosocial status, and problems in EQ-5D dimensions. In multiple regression analysis, the 50-59 age group showed a higher level of recognition for physical symptom needs and the unemployed group expressed greater needs for information and education. Survivors with multiplicity had greater needs in the domains of healthcare staff and physical symptom. The stress group showed high levels of needs in all domains except religious support. The group with thoughts of suicide showed higher levels of unmet needs for physical symptom.

Conclusion: Most prevalent unmet needs in Korean breast cancer survivors were found in the 'information and education' domain. The 50-59 age group, unemployment, multiplicity, stress and suicidal thoughts were associated with higher levels of unmet needs among Korean breast cancer survivors. Our findings revealed more vulnerable breast cancer survivors with unmet needs and physicians should take a precision approach to satisfy unmet needs of these survivors.
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http://dx.doi.org/10.1186/s12885-019-6064-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6712787PMC
August 2019

Site-specific phosphorylation of Fbxw7 by Cdk5/p25 and its resulting decreased stability are linked to glutamate-induced excitotoxicity.

Cell Death Dis 2019 08 2;10(8):579. Epub 2019 Aug 2.

Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul, 03722, Korea.

Cyclin-dependent kinase 5 (Cdk5) is a serine/threonine protein kinase that regulates brain development and neurodegeneration. Cdk5 is activated by p25 that is generated from calpain-dependent cleavage of p35. The generation of p25 is responsible for the aberrant hyper-activation of Cdk5, which causes neurodegeneration. Using in vitro assays, we discovered that F-box/WD repeat-containing protein 7 (Fbxw7) is a new substrate of Cdk5. Additionally, Cdk5-dependent phosphorylation of Fbxw7 was detected in the presence of p25, and two amino acid residues (S349 and S372) were determined to be major phosphorylation sites. This phosphorylation was eventually linked to decreased stability of Fbxw7. Using a culture model of cortical neurons challenged with glutamate, we confirmed that decreased stability of Fbxw7 was indeed Cdk5-dependent. Furthermore, diminished levels of Fbxw7 led to increased levels of transcription factor AP-1 (c-Jun), a known substrate of Fbxw7. Given that previous reports demonstrate that c-Jun plays a role in accelerating neuronal apoptosis in these pathological models, our data support the concepts of a molecular cascade in which Cdk5-mediated phosphorylation of Fbxw7 negatively regulates Fbxw7 expression, thereby contributing to neuronal cell death following glutamate-mediated excitotoxicity.
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http://dx.doi.org/10.1038/s41419-019-1818-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6675790PMC
August 2019

Protein kinase A-induced phosphorylation at the Thr154 affects stability of DJ-1.

Parkinsonism Relat Disord 2019 09 23;66:143-150. Epub 2019 Jul 23.

Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul, 03722, South Korea. Electronic address:

Introduction: Most cases of Parkinson's disease (PD) are sporadic, but genetic variations have been discovered in PD patients. PARK7/DJ-1 is a known cause of early-onset autosomal-recessive PD and is implicated in neuroprotection against oxidative stress. Although several post-translational modifications of DJ-1 have been proposed, phospho-modification of DJ-1 and its functional consequences have been less studied.

Methods: Putative phosphorylation sites of DJ-1 were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS analysis). Subsequently, phosphorylation site of DJ-1 was confirmed by in vitro kinase assay and cell-based pull-down assay. Impaired dimer formation of phospho-null mutant was measured using DSS crosslinking assay and immunoprecipitation assay. To evaluate physiological consequences of this event, protein stability of DJ-1 WT and DJ-1 phospho-null mutant were compared using cycloheximide chase assay and ubiquitination assay.

Results: Here, we showed that DJ-1 directly bound to the catalytic subunit of protein kinase A (PKAcα). We found that PKAcα is responsible for phosphorylation of DJ-1 at the T154 residue. Interestingly, dimerization of DJ-1 was not detected in a DJ-1 T154A mutant. Furthermore, stability of the DJ-1 T154A mutant was dramatically reduced compared with that of wild-type DJ-1. We found that DJ-1 T154A was prone to degradation by the ubiquitin proteasome system (UPS).

Conclusion: We identified a novel phosphorylation site of DJ-1. Furthermore, we determined protein kinase A that is responsible for this posttranslational modification. Finally, we demonstrated physiological consequences of this event focusing on dimerization and protein stability of DJ-1.
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http://dx.doi.org/10.1016/j.parkreldis.2019.07.029DOI Listing
September 2019

Dysregulated autophagy contributes to caspase-dependent neuronal apoptosis.

Cell Death Dis 2018 12 11;9(12):1189. Epub 2018 Dec 11.

Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul, 120-749, South Korea.

Autophagy is a regulated, intracellular degradation process that delivers unnecessary or dysfunctional cargo to the lysosome. Autophagy has been viewed as an adaptive survival response to various stresses, whereas in other cases, it promotes cell death. Therefore, both deficient and excessive autophagy may lead to cell death. In this study, we specifically attempted to explore whether and how dysregulated autophagy contributes to caspase-dependent neuronal cell death induced by the neurotoxin 6-hydroxydopamine (6-OHDA). Ultrastructural and biochemical analyses indicated that MN9D neuronal cells and primary cultures of cortical neurons challenged with 6-OHDA displayed typical features of autophagy. Cotreatment with chloroquine and monitoring autophagic flux by a tandem mRFP-EGFP-tagged LC3 probe indicated that the autophagic phenomena were primarily caused by dysregulated autophagic flux. Consequently, cotreatment with an antioxidant but not with a pan-caspase inhibitor significantly blocked 6-OHDA-stimulated dysregulated autophagy. These results indicated that 6-OHDA-induced generation of reactive oxygen species (ROS) played a critical role in triggering neuronal death by causing dysregulated autophagy and subsequent caspase-dependent apoptosis. The results of the MTT reduction, caspase-3 activation, and TUNEL assays indicated that pharmacological inhibition of autophagy using 3-methyladenine or deletion of the autophagy-related gene Atg5 significantly inhibited 6-OHDA-induced cell death. Taken together, our results suggest that abnormal induction of autophagic flux promotes apoptotic neuronal cell death, and that the treatments limiting dysregulated autophagy may have a strong neuroprotective potential.
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http://dx.doi.org/10.1038/s41419-018-1229-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6289995PMC
December 2018

The Roles of Endo-Lysosomes in Unconventional Protein Secretion.

Cells 2018 Nov 3;7(11). Epub 2018 Nov 3.

Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

Protein secretion in general depends on signal sequence (also named leader sequence), a hydrophobic segment located at or close to the NH2-terminus of a secretory or membrane protein. This sequence guides the entry of nascent polypeptides into the lumen or membranes of the endoplasmic reticulum (ER) for folding, assembly, and export. However, evidence accumulated in recent years has suggested the existence of a collection of unconventional protein secretion (UPS) mechanisms that are independent of the canonical vesicular trafficking route between the ER and the plasma membrane (PM). These UPS mechanisms export soluble proteins bearing no signal sequence. The list of UPS cargos is rapidly expanding, along with the implicated biological functions, but molecular mechanisms accountable for the secretion of leaderless proteins are still poorly defined. This review summarizes our current understanding of UPS mechanisms with an emphasis on the emerging role of endo-lysosomes in this process.
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http://dx.doi.org/10.3390/cells7110198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6262434PMC
November 2018

NK1.1 Expression Defines a Population of CD4 Effector T Cells Displaying Th1 and Tfh Cell Properties That Support Early Antibody Production During Infection.

Front Immunol 2018 15;9:2277. Epub 2018 Oct 15.

Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.

Early plasmablast induction is a hallmark of infection and is thought to contribute to the control of acute parasite burden. Although long understood to be a T-cell dependent phenomenon, regulation of early plasmablast differentiation, however, is poorly understood. Here, we identify a population of CD4 T cells that express the innate NK cell marker NK1.1 as an important source of T cell help for early plasmablast and parasite-specific Ab production. Interestingly, NK1.1 CD4 T cells arise from conventional, naive NK1.1 CD4 T cells, and their generation is independent of CD1d but critically reliant on MHC-II. CD4 T cells that express NK1.1 early after activation produce IFN-γ and IL-21, and express the follicular helper T (Tfh) cell markers ICOS, PD-1 and CXCR5 more frequently than NK1.1 CD4 T cells. Further analysis of this population revealed that NK1.1 Tfh-like cells were more regularly complexed with plasmablasts than NK1.1 Tfh-like cells. Ultimately, depletion of NK1.1 cells impaired class-switched parasite-specific antibody production during early infection. Together, these data suggest that expression of NK1.1 defines a population of rapidly expanding effector CD4 T cells that specifically promote plasmablast induction during infection and represent a subset of T cells whose modulation could promote effective vaccine design.
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http://dx.doi.org/10.3389/fimmu.2018.02277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6196288PMC
September 2019

The comparison of two different intraarticular injections using a sonographic anterolateral approach in patients with osteoarthritic knee.

Korean J Pain 2018 Oct 1;31(4):289-295. Epub 2018 Oct 1.

Department of Anesthesiology and Pain Medicine, Chonbuk National University Medical School and Hospital, Jeonju, Korea.

Background: The intraarticular (IA) injection has become popular for the management of the osteoarthritic knee without an effusion. The success rate of IA injection would be better if it was able to be visually confirmed. We hypothesized that an anterolateral approach, which targets the synovial membrane of the lateral condyle using ultrasound, would provide an equivalent alternative to the anterolateral approach, targeting the synovial membrane of the medial condyle for IA injection of the knee.

Methods: A total of 96 knees with osteoarthritis were randomized placed into the two groups, which were group I (anterolateral approach to the medial condyle) and group II (anterolateral approach to the lateral condyle). The primary outcome was to compare the success rate of the two methods of IA injection. The required length of the needle for injection was also measured and compared. Pain intensity was assessed using the Numeric Rating Scale in order to evaluate the success of injection.

Results: There were no significant differences in the success rate between both groups. The success rate of group I and group II were 87.8% (95%, CI 78.7-97.0) and 91.5% (95%, CI 83.6-99.5), respectively ( = 0.549). The needle depth was 5.0 ± 0.8 (3.0 to 6.1 cm) in group I, and 3.0 ± 0.8 (1.5 to 5 cm) in group II ( < 0.001).

Conclusions: The anterolateral approach to the lateral femoral condyle, using ultrasound, is an alternative method to the approach targeting the medial femoral condyle, using shorter needle.
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http://dx.doi.org/10.3344/kjp.2018.31.4.289DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6177542PMC
October 2018

The acetylation of cyclin-dependent kinase 5 at lysine 33 regulates kinase activity and neurite length in hippocampal neurons.

Sci Rep 2018 09 12;8(1):13676. Epub 2018 Sep 12.

Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul, 03722, Republic of Korea.

Cyclin-dependent kinase 5 (CDK5) plays a pivotal role in neural development and neurodegeneration. CDK5 activity can be regulated by posttranslational modifications, including phosphorylation and S-nitrosylation. In this study, we demonstrate a novel mechanism by which the acetylation of CDK5 at K33 (Ac-CDK5) results in the loss of ATP binding and impaired kinase activity. We identify GCN5 and SIRT1 as critical factor controlling Ac-CDK5 levels. Ac-CDK5 achieved its lowest levels in rat fetal brains but was dramatically increased during postnatal periods. Intriguingly, nuclear Ac-CDK5 levels negatively correlated with neurite length in embryonic hippocampal neurons. Either treatment with the SIRT1 activator SRT1720 or overexpression of SIRT1 leads to increases in neurite length, whereas SIRT1 inhibitor EX527 or ectopic expression of acetyl-mimetic (K33Q) CDK5 induced the opposite effect. Furthermore, the expression of nuclear-targeted CDK5 K33Q abolished the SRT1720-induced neurite outgrowth, showing that SIRT1 positively regulates neurite outgrowth via deacetylation of nuclear CDK5. The CDK5 activity-dependent increase of neurite length was mediated by enhanced transcriptional regulation of BDNF via unknown mechanism(s). Our findings identify a novel mechanism by which acetylation-mediated regulation of nuclear CDK5 activity plays a critical role in determining neurite length in embryonic neurons.
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http://dx.doi.org/10.1038/s41598-018-31785-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6135752PMC
September 2018

Secretion of misfolded cytosolic proteins from mammalian cells is independent of chaperone-mediated autophagy.

J Biol Chem 2018 09 2;293(37):14359-14370. Epub 2018 Aug 2.

From the Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892,

In eukaryotic cells, elimination of misfolded proteins is essential for maintaining protein homeostasis and cell viability. Misfolding-associated protein secretion (MAPS) is a protein quality-control mechanism that exports misfolded cytosolic proteins via a compartment characteristic of late endosomes, but how cytosolic proteins enter this compartment is unclear. Because chaperone-mediated autophagy (CMA) is a known mechanism that imports cytosolic proteins bearing a specific CMA motif to lysosomes for degradation and because late endosomes and lysosomes overlap significantly in mammalian cells, we determined here whether CMA is involved in targeting protein cargoes to the lumen of late endosomes in MAPS. Using HEK293T and COS-7 cells and immunoblotting and -staining and coimmunoprecipitation methods, we show that, unlike CMA, the secretion of misfolded proteins in MAPS does not require cargo unfolding, is inhibited by serum starvation, and is not dependent on the CMA motif in cargo. Intriguingly, knockdown of lysosome-associated membrane protein 2 (LAMP2), which consists of three isoforms, including a variant proposed to form a protein channel on lysosomes for CMA, attenuated MAPS. However, this could not be attributed to the proposed channel function of the LAMP2a isoform because overexpression of a cytosolic MAPS stimulator, DnaJ heat shock protein family (Hsp40) member C5 (DNAJC5), fully rescued the secretion defect associated with LAMP2 deficiency. We conclude that, in MAPS, cargoes use a CMA-independent mechanism to enter a nondegradative prelysosomal compartment.
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http://dx.doi.org/10.1074/jbc.RA118.003660DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6139554PMC
September 2018

Identifying labile DOM components in a coastal ocean through depleted bacterial transcripts and chemical signals.

Environ Microbiol 2018 08 30;20(8):3012-3030. Epub 2018 Jul 30.

Department of Marine Sciences, University of Georgia, Athens, GA, USA.

Understanding which compounds comprising the complex and dynamic marine dissolved organic matter (DOM) pool are important in supporting heterotrophic bacterial production remains a major challenge. We eliminated sources of labile phytoplankton products, advected terrestrial material and photodegradation products to coastal microbial communities by enclosing water samples in situ for 24 h in the dark. Bacterial genes for which expression decreased between the beginning and end of the incubation and chemical formulae that were depleted over this same time frame were used as indicators of bioavailable compounds, an approach that avoids augmenting or modifying the natural DOM pool. Transport- and metabolism-related genes whose relative expression decreased implicated osmolytes, carboxylic acids, fatty acids, sugars and organic sulfur compounds as candidate bioreactive molecules. FT-ICR MS analysis of depleted molecular formulae implicated functional groups ~ 30-40 Da in size cleaved from semi-polar components of DOM as bioreactive components. Both gene expression and FT-ICR MS analyses indicated higher lability of compounds with sulfur and nitrogen heteroatoms. Untargeted methodologies able to integrate biological and chemical perspectives can be effective strategies for characterizing the labile microbial metabolites participating in carbon flux.
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http://dx.doi.org/10.1111/1462-2920.14344DOI Listing
August 2018

DNAJC5 facilitates USP19-dependent unconventional secretion of misfolded cytosolic proteins.

Cell Discov 2018 6;4:11. Epub 2018 Mar 6.

Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 USA.

Cell-to-cell transmission of misfolded proteins propagates proteotoxic stress in multicellular organisms when transmitted polypeptides serve as a seeding template to cause protein misfolding in recipient cells, but how misfolded proteins are released from cells to initiate this process is unclear. Misfolding-associated protein secretion (MAPS) is an unconventional protein-disposing mechanism that specifically exports misfolded cytosolic proteins including various neurodegenerative disease-causing proteins. Here we establish the HSC70 co-chaperone DNAJC5 as an essential mediator of MAPS. USP19, a previously uncovered MAPS regulator binds HSC70 and acts upstream of HSC70 and DNAJC5. We further show that as a membrane-associated protein localized preferentially to late endosomes and lysosomes, DNAJC5 can chaperone MAPS client proteins to the cell exterior. Intriguingly, upon secretion, misfolded proteins can be taken up through endocytosis and eventually degraded in the lysosome. Collectively, these findings suggest a transcellular protein quality control regulatory pathway in which a deubiquitinase-chaperone axis forms a "triaging hub", transferring aberrant polypeptides from stressed cells to healthy ones for disposal.
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http://dx.doi.org/10.1038/s41421-018-0012-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5838229PMC
March 2018

Cyclin-dependent kinase 5-mediated phosphorylation of CHIP promotes the tAIF-dependent death pathway in rotenone-treated cortical neurons.

Neurosci Lett 2018 Jan 27;662:295-301. Epub 2017 Oct 27.

Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul 120-749, Republic of Korea. Electronic address:

Cyclin-dependent kinase 5 (Cdk5) is a proline-directed serine/threonine kinase. Its dysregulation has been implicated in various neurodegenerative diseases. We previously reported that phosphorylation of the C-terminus of the Hsc70-interacting protein (CHIP) by Cdk5 promotes truncated apoptosis-inducing factor (tAIF)-mediated neuronal death induced by oxidative stress. Here, we determined whether this Cdk5-dependent cell death signaling pathway is present in experimental models of Parkinson's disease. First, we showed that rotenone activates Cdk5 in primary cultures of cortical neurons and causes tAIF-dependent neuronal cell death. This event was attenuated by negative regulation of endogenous Cdk5 activity by the pharmacological Cdk5 inhibitor, roscovitine, or by lentiviral knockdown of Cdk5. Cdk5 phosphorylates CHIP at Ser20 in rotenone-treated neurons. Consequently, overexpression of CHIP, but not CHIP, attenuates tAIF-induced cell death in rotenone-treated cortical neurons. Taken together, these results indicate that phosphorylation of CHIP at Ser20 by Cdk5 activation inhibits CHIP-mediated tAIF degradation, thereby contributing to tAIF-induced neuronal cell death following rotenone treatment.
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http://dx.doi.org/10.1016/j.neulet.2017.10.053DOI Listing
January 2018

Assembly of polymer micelles through the sol-gel transition for effective cancer therapy.

J Control Release 2017 06 26;255:258-269. Epub 2017 Apr 26.

College of Pharmacy, Korea University, 2511 Sejongro, Sejong 30019, Republic of Korea; Biomedical Research Center, Korea University Guro Hospital, Guro-gu, Seoul 08308, Republic of Korea. Electronic address:

Photo-induced apoptosis-targeted chemotherapy (PIATC) was designed and characterized to propose a new protocol for improved chemotherapy. Intratumoral injection was selected as the mode of administration of the anticancer drug, doxorubicin (DOX). To extend the retention time of DOX at the tumor parenchyma, in-situ gel formation was induced through the sol-gel transition of the Pluronic NPs containing a prodrug of DOX or a photosensitizer. The prodrug (DEVD-S-DOX) was designed to be inactive with a peptide moiety (Aspartic acid-Glutamic acid-Valine-Aspartic acid: DEVD) linked to DOX and to be cleaved into free DOX by caspase-3 expressed with apoptosis. For reactive oxygen species (ROS)-mediated apoptosis, photo-irradiation with methylene blue (MB, photosensitizer) was utilized. The sol-gel transition of the Pluronic NPs containing reactive species, DEVD-S-DOX or MB, was examined by measuring the cloud point and the gel strength in response to temperature change. ROS-mediated apoptosis was observed by measuring the ROS and membrane integrity with induced apoptosis. The in vivo antitumor efficacy of PIATC was measured with a cardiotoxicity assay in tumor-bearing mice.
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http://dx.doi.org/10.1016/j.jconrel.2017.04.039DOI Listing
June 2017

Factors associated with abnormal pulmonary function test among subjects with normal chest radiography: The Korean National Health and Nutrition Examination Survey.

Respirology 2016 10 20;21(7):1330-2. Epub 2016 Jun 20.

Department of Preventive Medicine, Chonbuk National University Medical School, Jeonju, Korea.

Determinants of abnormal lung function among subjects with normal chest radiography have not been widely evaluated. We investigated 12 109 participants with normal chest radiographs from the Korean National Health and Nutrition Examination Survey. Factors associated with abnormal pulmonary function were male gender, age ≥50, smoking history and a clinical history of cough or sputum production. Pulmonary function tests should be considered in population-based screening, especially in men over 50 years old with a smoking history.
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http://dx.doi.org/10.1111/resp.12833DOI Listing
October 2016

Enhanced M2 macrophage polarization in high n-3 polyunsaturated fatty acid transgenic mice fed a high-fat diet.

Mol Nutr Food Res 2016 11 12;60(11):2481-2492. Epub 2016 Jul 12.

Department of Biochemistry Preventive Medicine, Chonbuk National University Medical School, Jeonju, Jeonbuk, Republic of Korea.

Scope: Diet-induced obesity and consequent insulin resistance are caused, in part, by macrophage polarization and accumulation in peripheral tissues. Here, we examined the effects of endogenously synthesized n-3 PUFAs on macrophage chemotaxis and polarization.

Methods And Results: Fat-1 mice and wild-type (WT) littermates were fed a 60% calorie high-fat diet (HFD) for 10 weeks. Bone marrow macrophages (BMMs) from fat-1 and WT mice were used in in vitro chemotaxis assays and macrophage polarization studies. WT mice fed a HFD exhibited glucose intolerance, insulin resistance, and lipid accumulation and macrophage infiltration in liver and adipose tissue. However, these metabolic and inflammatory phenotypes were not observed in HFD-fed fat-1 mice. In flow cytometric analysis, M1 macrophage infiltration into adipose tissue was markedly attenuated in fat-1 mice. Consistently, results from in vitro experiments indicated that n-3 PUFAs prevented adipocyte conditioned medium-mediated macrophage chemotaxis, stimulated M2 polarization, and suppressed M1 polarization. The inhibition of macrophage migration by n-3 PUFAs was associated with suppression of multiple kinases, such as IκB kinase, AKT, and focal adhesion kinase.

Conclusion: Our results indicate that n-3 PUFAs play a crucial role in macrophage polarization and chemotaxis, and thus regulate the development of HFD-induced tissue inflammation and metabolic derangements.
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http://dx.doi.org/10.1002/mnfr.201600014DOI Listing
November 2016

The reality in the follow-up of breast cancer survivors: survey of Korean Breast Cancer Society.

Ann Surg Treat Res 2015 Mar 27;88(3):133-9. Epub 2015 Feb 27.

Department of Surgery, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.

Purpose: Follow-up after primary treatment for breast cancer is an important component of survivor care and various international guidelines exist for the surveillance. However, little is known about current actual practice patterns of physicians whether they adhere to or deviate from recommended guidelines. The aim of this study was to determine how physicians follow-up their patients after primary treatment for breast cancer in Korea.

Methods: A questionnaire survey with 34 questions in 4 categories was e-mailed to the members of Korean Breast Cancer Society from November to December 2013. Respondents were asked how they use follow-up modalities after primary treatment of breast cancer and we compared the survey results with present guidelines.

Results: Of the 129 respondents, 123 (95.3%) were breast surgeons. The most important consideration in follow-up was tumor stage. History taking, physical examinations, and mammography were conducted in similar frequency recommended by other guidelines while breast ultrasonography was performed more often. The advanced imaging studies such as CT, MRI, and bone scan, which had been recommended to be conducted only if necessary, were also examined more frequently. Regular screenings for secondary malignancy were performed in 38 respondents (29.5%). Five years later after primary treatment, almost the whole respondents (94.6%) themselves monitored their patients.

Conclusion: A majority of respondents have been performed more intensive follow-up modalities in comparison with present guidelines and less frequently screenings for secondary malignancy. For optimal follow-up of breast cancer survivors, tailored delivery system should be considered.
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http://dx.doi.org/10.4174/astr.2015.88.3.133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4347047PMC
March 2015

Acetylation of cyclin-dependent kinase 5 is mediated by GCN5.

Biochem Biophys Res Commun 2014 Apr 1;447(1):121-7. Epub 2014 Apr 1.

Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul 120-749, Republic of Korea. Electronic address:

Cyclin-dependent kinase 5 (CDK5), a member of atypical serine/threonine cyclin-dependent kinase family, plays a crucial role in pathophysiology of neurodegenerative disorders. Its kinase activity and substrate specificity are regulated by several independent pathways including binding with its activator, phosphorylation and S-nitrosylation. In the present study, we report that acetylation of CDK5 comprises an additional posttranslational modification within the cells. Among many candidates, we confirmed that its acetylation is enhanced by GCN5, a member of the GCN5-related N-acetyl-transferase family of histone acetyltransferase. Co-immunoprecipitation assay and fluorescent localization study indicated that GCN5 physically interacts with CDK5 and they are co-localized at the specific nuclear foci. Furthermore, liquid chromatography in conjunction with a mass spectrometry indicated that CDK5 is acetylated at Lys33 residue of ATP binding domain. Considering this lysine site is conserved among a wide range of species and other related cyclin-dependent kinases, therefore, we speculate that acetylation may alter the kinase activity of CDK5 via affecting efficacy of ATP coordination.
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http://dx.doi.org/10.1016/j.bbrc.2014.03.118DOI Listing
April 2014

Spectroscopic and functional characterization of human beta-synuclein.

Protein Pept Lett 2007 ;14(10):1021-6

Department of Molecular Science and Technology, Graduate School of Interdisciplinary Program, Ajou University, Suwon, South Korea.

To elucidate potential biological roles of human beta-synuclein, we studied its conformational changes under various conditions. The structural and functional properties of beta-synuclein were characterized using biochemical and bio-physical methods including: a functional assay, mass spectrometry, size exclusion chromatography, circular dichroism (CD), and fluorescence spectroscopy. The results showed beta-synuclein has a high proportion of random coil in solution.
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http://dx.doi.org/10.2174/092986607782541132DOI Listing
March 2008

New and known symmetrical curcumin derivatives inhibit the formation of Fos-Jun-DNA complex.

Cancer Lett 2002 Oct;184(1):89-96

Division of Chemistry and Molecular Engineering, Seoul National University, San 56-1, Shillim-dong, Kwanak-gu, South Korea.

We previously reported that curcumin, the yellow pigment of turmeric, inhibited the formation of the Fos-Jun-DNA complex. Thus, we have synthesized 12 symmetrical curcuminoids. We used a slightly modified version of Pabon's method to search for an inhibitor more potent than curcumin. Of the synthesized curcuminoids, BJC005, CHC011, and CHC007 exhibited a remarkably high inhibitory activity. Their IC(50) values are 5.4 microM, 0.30 mM, and 0.38 mM, respectively. These IC(50) data indicated that BJC005 is nearly 90 times more effective than curcumin. The BJC005 has shown a more powerful profile than momordin, which, until now, has been reported as a potent Fos-Jun inhibitor. Also BJC005 and CHC007 have not been synthesized before. We report for the first time that the novel BJC005 and CHC007 exhibit highly inhibitory activity against transcription activity.
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http://dx.doi.org/10.1016/s0304-3835(02)00170-2DOI Listing
October 2002