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1.
J Neurosci Res ; 102(1): e25251, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37818759

ABSTRACT

3-Fluoroethamphetamine (3-FEA) belongs to the amphetamine class of stimulant drugs and functions as a releasing agent for the monoamine neurotransmitters norepinephrine, dopamine, and serotonin. 3-FEA acts on the central nervous system and elicits physical and mental side effects, such as euphoria, increased heart rate, and excitement. However, little is known about the withdrawal symptoms and behavioral changes induced by 3-FEA administration. This study aimed to evaluate the short-term consequences of 3-FEA administration (twice a day, 7 days, i.p.; 1 and 10 mg/kg) in C57BL/6J mice (male, 7 weeks old) at three behavioral levels following 1-4 days of withdrawal. The evaluation included (1) withdrawal score, (2) hyperactivity (open field [OF], elevated plus maze [EPM], and cliff avoidance [CA] test), and (3) depression-like behavior (forced-swim test). In the withdrawal score test, withdrawal behavior increased in all 3-FEA groups at 16 and 40 h after withdrawal. In the OF, EPM, and CA tests, the 3-FEA administration group showed significant changes in terms of hyperactivity. In addition, in the forced-swim test, both the 1 mg/kg and 10 mg/kg 3-FEA groups showed increased immobility time. These findings indicate that 3-FEA administration may lead to physical dependence, demonstrated by the withdrawal score increase and significant changes in hyperactivity and depression-like behavior following repeated administration and drug cessation. In conclusion, this study reveals the adverse consequences of 3-FEA administration and highlights the need for awareness raising and regulatory action to control the use of this new psychoactive substance.


Subject(s)
Depression , Substance Withdrawal Syndrome , Mice , Male , Animals , Depression/chemically induced , Depression/drug therapy , Mice, Inbred C57BL , Amphetamine/pharmacology , Swimming , Substance Withdrawal Syndrome/drug therapy , Behavior, Animal , Anxiety
2.
Chemistry ; 30(49): e202401733, 2024 Sep 02.
Article in English | MEDLINE | ID: mdl-38934891

ABSTRACT

In several biological processes, H2S is known to function as an endogenous gaseous agent. It is very necessary to monitor H2S and relevant physiological processes in vivo. Herein, a new type of fluorophore with a reliable leaving group allows for excited-state intramolecular transfer characteristics (ESIPT), inspired by mycophenolic acid. A morpholine ring was connected at the maleimide position of the probe to target the lysosome. Subsequently, the dinitrophenyl group known for a photoinduced electron transfer (PET) effect, was connected to allow for an effective "turn-on" probe Lyso-H2S. Lyso-H2S demonstrated strong selectivity towards H2S, a large Stokes shift (111 nm), and an incredibly low detection limit (41.8 nM). The imaging of endogenous and exogenous H2S in living cells (A549 cell line) was successfully achieved because of the specificity and ultra-low toxicity (100 % cell viability at 50 µM concentration of Lyso-H2S.) Additionally, Lyso-H2S was also employed to visualize the activity of H2S in the gallbladder and intestine in a living zebrafish model. This is the first report of a fluorescent probe to track H2S sensing in specific organ systems to our knowledge.


Subject(s)
Fluorescent Dyes , Hydrogen Sulfide , Mycophenolic Acid , Zebrafish , Animals , Mycophenolic Acid/chemistry , Hydrogen Sulfide/analysis , Hydrogen Sulfide/chemistry , Fluorescent Dyes/chemistry , Humans , A549 Cells , Cell Survival/drug effects , Limit of Detection , Optical Imaging , Lysosomes/metabolism , Lysosomes/chemistry , Morpholines/chemistry
3.
Analyst ; 149(17): 4477-4486, 2024 Aug 19.
Article in English | MEDLINE | ID: mdl-39041806

ABSTRACT

Innovative for the scientific community and attracting attention in the extensive biomedical field are novel compact organic chemosensing systems built upon unique core molecular frameworks. These systems may demonstrate customized responses and may be adaptable to analytes, showing promise for potential in vivo applications. Our recent investigation focuses on a precursor of Mycophenolic acid, resulting in the development of LBM (LOD = 13 nM) - a specialized probe selective for H2O2. This paper details the synthesis, characterization, and thorough biological assessments of LBM. Notably, we conducted experiments involving living cells, daphnia, and zebrafish models, utilizing microscopy techniques to determine probe nontoxicity and discern distinct patterns of probe localization. Localization involved the distribution of the probe in the Zebrafish model within the gut, esophagus, and muscles of the antennae.


Subject(s)
Daphnia , Fluorescent Dyes , Hydrogen Peroxide , Mycophenolic Acid , Zebrafish , Animals , Hydrogen Peroxide/chemistry , Mycophenolic Acid/chemistry , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Daphnia/chemistry , Humans , Limit of Detection , HeLa Cells , Optical Imaging , Daphnia magna
4.
J Neurochem ; 165(5): 660-681, 2023 06.
Article in English | MEDLINE | ID: mdl-36648143

ABSTRACT

Schwann cells (SCs) are known to produce myelin for saltatory nerve conduction in the peripheral nervous system (PNS). Schwann cell differentiation and myelination processes are controlled by several transcription factors including Sox10, Oct6/Pou3f1, and Krox20/Egr2. Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII/NR2F2) is an orphan receptor that plays a role in the development and differentiation. However, the role of COUP-TFII in the transcriptional regulatory network of SC differentiation has not been fully identified yet. Thus, the objective of this study was to investigate the role and molecular hierarchy of COUP-TFII during cAMP-induced SC differentiation. Our results showed that dibutyryl-cAMP (db-cAMP) increased expression levels of COUP-TFII along with the expressions of Oct6, Krox20, and myelin-related genes known to be related to SC differentiation. Our mechanistic studies showed that COUP-TFII acted downstream of Hsp90/ErbB2/Gab1/ERK-AKT pathway during db-cAMP-induced SC differentiation. In addition, we found that COUP-TFII induced Krox20 expression by directly binding to Krox20-MSE8 as revealed by chromatin immunoprecipitation assay and promoter activity assay. In line with this, the expression of COUP-TFII was increased before up-regulation of Oct6, Krox20, and myelin-related genes in the sciatic nerves during early postnatal myelination period. Finally, COUP-TFII knockdown by COUP-TFII siRNA or via AAV-COUP-TFII shRNA in SCs inhibited db-cAMP-induced SC differentiation and in vitro myelination of sensory axons, respectively. Taken together, these findings indicate that COUP-TFII might be involved in postnatal myelination through induction of Krox20 in SCs. Our results present a new insight into the transcriptional regulatory mechanism in SC differentiation and myelination.


Subject(s)
COUP Transcription Factor II , Early Growth Response Protein 2 , Schwann Cells , Animals , Rats , Cell Differentiation , Cells, Cultured , COUP Transcription Factor II/genetics , COUP Transcription Factor II/metabolism , Cyclic AMP/metabolism , Gene Expression Regulation , Myelin Sheath/metabolism , Schwann Cells/cytology , Schwann Cells/metabolism , Sciatic Nerve/metabolism , Early Growth Response Protein 2/metabolism
5.
J Happiness Stud ; 24(2): 455-476, 2023.
Article in English | MEDLINE | ID: mdl-36471764

ABSTRACT

This study estimates the effects of the COVID-19 pandemic on life satisfaction and stress and examines whether these effects vary across different sociodemographic groups using a nationally representative sample in South Korea. We estimate the causal effects of COVID-19 on psychological well-being by exploiting regional variation in the spread of the pandemic in South Korea. While the number of confirmed cases was very small in other provinces in the first half of 2020, the coronavirus spread rapidly in Daegu after an outbreak in one church. We employ a difference-in-differences approach that compares changes in people's life satisfaction and stress before-and-after the initial surge of COVID-19 cases in Daegu and other provinces. Our results show that the proportion of people who are dissatisfied with life increased by 2.8-6.5 percentage points more in Daegu than in other provinces after the COVID-19 outbreak. During the same period, the proportion of people who reported feeling stressed increased more in Daegu than in other provinces by 5.8-8.9 percentage points. Our results also suggest that the negative impact of the COVID-19 outbreak on psychological well-being is significantly greater for men, young adults, middle-aged adults, self-employed workers, and middle-income individuals. On the other hand, the proportion of people who report feeling stressed among the highest-educated (a master's degree or higher) and high-income individuals decreased after the onset of the COVID-19 outbreak.

6.
Health Expect ; 25(2): 732-743, 2022 04.
Article in English | MEDLINE | ID: mdl-34989087

ABSTRACT

INTRODUCTION: Multistakeholder engagement is crucial for conducting health services research. Delphi-based methodologies combining iterative rounds of questions with feedback on and discussion of group results are a well-documented approach to multistakeholder engagement. This study develops hypotheses about the impact of panel composition and topic on the propensity and meaningfulness of response changes in multistakeholder modified-Delphi panels. METHODS: We conducted three online modified-Delphi (OMD) multistakeholder panels using the same protocol. We assigned 60 maternal and child health professionals to a homogeneous (professionals only) panel, 60 pregnant or postpartum women (patients) to a homogeneous panel, and 30 professionals and 30 patients to a mixed panel. In Round 1, participants rated the seriousness of 11 maternal and child health outcomes using a 0-100 scale and explained their ratings. In Round 2, participants saw their own and their panel's Round 1 results and discussed them using asynchronous, anonymous discussion boards moderated by the study investigators. In Round 3, participants revised their original ratings. Our outcome measures included binary indicators of response changes to ratings of the low, medium and high severity maternal and child health outcomes and their meaningfulness, measured by a change of 10 or more points. RESULTS: Participants changed 818 of 1491 (55%) of responses; the majority of response changes were meaningful. Patterns of response changes were different for patients and professionals and for different levels of outcome seriousness. Using study results and the literature, we developed three hypotheses. First, OMD participants, regardless of their stakeholder group, are more likely to change their responses on preference-sensitive topics where there is a range of viable alternatives or perspectives. Second, patients are more likely to change their responses and to do so meaningfully in mixed panels, whereas professionals are more likely to do so in homogeneous panels. Third, the association between panel composition and response change varies according to the topic (e.g., the level of outcome seriousness). CONCLUSIONS: Results of our work not only helped generate empirically derived hypotheses to be tested in future research but also offer practical recommendations for designing multistakeholder OMD panels. PATIENT OR PUBLIC CONTRIBUTION: Pregnant or postpartum women were involved in this study.


Subject(s)
Child Health , Health Services Research , Child , Delphi Technique , Family , Female , Health Personnel , Humans , Pregnancy
7.
BMC Biol ; 19(1): 44, 2021 04 01.
Article in English | MEDLINE | ID: mdl-33789631

ABSTRACT

BACKGROUND: IK is a splicing factor that promotes spliceosome activation and contributes to pre-mRNA splicing. Although the molecular mechanism of IK has been previously reported in vitro, the physiological role of IK has not been fully understood in any animal model. Here, we generate an ik knock-out (KO) zebrafish using the CRISPR/Cas9 system to investigate the physiological roles of IK in vivo. RESULTS: The ik KO embryos display severe pleiotropic phenotypes, implying an essential role of IK in embryonic development in vertebrates. RNA-seq analysis reveals downregulation of genes involved in skeletal muscle differentiation in ik KO embryos, and there exist genes having improper pre-mRNA splicing among downregulated genes. The ik KO embryos display impaired neuromuscular junction (NMJ) and fast-twitch muscle development. Depletion of ik reduces myod1 expression and upregulates pax7a, preventing normal fast muscle development in a non-cell-autonomous manner. Moreover, when differentiation is induced in IK-depleted C2C12 myoblasts, myoblasts show a reduced ability to form myotubes. However, inhibition of IK does not influence either muscle cell proliferation or apoptosis in zebrafish and C2C12 cells. CONCLUSION: This study provides that the splicing factor IK contributes to normal skeletal muscle development in vivo and myogenic differentiation in vitro.


Subject(s)
Cytokines/genetics , Muscle, Skeletal/embryology , RNA Splicing Factors/genetics , Zebrafish Proteins/genetics , Zebrafish/genetics , Animals , Animals, Genetically Modified , Cytokines/metabolism , Embryo, Nonmammalian/embryology , Embryo, Nonmammalian/metabolism , Embryonic Development , RNA Splicing Factors/metabolism , Zebrafish/embryology , Zebrafish/metabolism , Zebrafish Proteins/metabolism
8.
Biochem Biophys Res Commun ; 509(3): 674-679, 2019 02 12.
Article in English | MEDLINE | ID: mdl-30612732

ABSTRACT

Adult hippocampal neural (HCN) stem cells promptly undergo irreversible autophagic cell death (ACD) if deprived of insulin in culture. Small, non-coding microRNAs (miRNA) play an important role in regulating biological processes, including proliferation and cell death. However, there have been no reports thus far regarding miRNA involvement in the induction of adult HCN stem cell death under insulin-deprived conditions, for which we performed a microarray-based analysis to examine the expression signature of miRNAs in adult rat HCN stem cells. Three independent specimens per culture condition either with or without insulin were prepared and a miRNA microarray analysis carried out. A total of 12 exhibited significantly altered expression levels upon cell death due to the absence of insulin when compared to HCN stem cells cultured with insulin present (cut-off limit; p < 0.05 and fold-change >1.3) The resulting volcano plot showed that, among these miRNAs, seven were upregulated and five were downregulated. The upregulated miRNAs were capable of modulating HCN stem cell death. Caspase-3 activity analysis, LC3 conversion, and TEM of autophagosome formation consistently suggested that ACD, not apoptosis, was most likely the mechanism affecting HCN cell death. As such, we have come to term these miRNAs, "HCN stem cell-specific autophagic cell death regulators." Taken together, our data suggest that the miRNA expression profile of HCN stem cells is altered during ACD occurring due to insulin deprivation and that differentially expressed miRNAs are involved in HCN stem cell viability. Detailed explorations of the underlying mechanisms regarding HCN stem cell viability modulation by these miRNAs would be beneficial in further understanding the physiological features of adult HCN stem cells and are currently being investigated.


Subject(s)
Adult Stem Cells/cytology , Autophagy , Hippocampus/cytology , MicroRNAs/genetics , Neural Stem Cells/cytology , Transcriptome , Adult Stem Cells/metabolism , Animals , Cell Death , Cell Line , Gene Expression Profiling , Hippocampus/metabolism , Insulin/metabolism , Neural Stem Cells/metabolism , Rats
9.
Prev Med ; 129: 105846, 2019 12.
Article in English | MEDLINE | ID: mdl-31518627

ABSTRACT

Women use parks less for physical activity than men, and explanations include gendered concerns regarding personal safety and access to walking paths. This study conducted mediation analyses to examine the effects of gender and presence of park walking path on park use, participation in park programs, and park-based physical activity through the hypothesized mediator (perception of crime). The sample included 3213 park users from 48 parks in high poverty neighborhoods in Los Angeles surveyed between 2013 and 2015; park-level factors were assessed through systematic observations of study parks. Women reported fewer park visits than men in the last 7 days (ß = -0.17, p = 0.02) and had significantly higher perceived crime (ß = 0.12, p < 0.0001) and perceived crime partially mediated the gender association with park visits (ßgender, direct = -0.09, p = 0.19; ßgender, indirect = -0.07, p < 0.0001). Similarly, the existence of a walking path in the park was significantly related to increased park use (ß = 0.27, p = 0.006) and a lower level of perceived crime (ß = -0.25, p = 0.0034) and perceived crime partially mediated the association of walking path with park visits (ßwalking path, direct = 0.18, p = 0.10; ßwalking path, indirect = 0.15, p = 0.005). The associations between gender, walking path, and park-based exercise and program participation were not meaningfully mediated by perceived crime. Among park users in majority Latino, high poverty neighborhoods, addressing crime concerns are likely necessary to increase park use among women and adults whose parks do not have a walking path. For park-based exercise and participation in park programs, gendered preferences regarding park-based physical activity should be explored.


Subject(s)
Built Environment , Crime/statistics & numerical data , Ethnicity , Exercise/physiology , Parks, Recreational/statistics & numerical data , Adult , Ethnicity/psychology , Ethnicity/statistics & numerical data , Female , Humans , Los Angeles , Male , Poverty , Residence Characteristics , Safety , Sex Factors , Urban Population , Walking/statistics & numerical data
10.
J Aging Phys Act ; 27(3): 334-342, 2019 06 01.
Article in English | MEDLINE | ID: mdl-30160585

ABSTRACT

Routine physical activity is important for everyone, and most urban areas have an infrastructure of neighborhood parks that are intended to serve as a setting for recreation and leisure. However, parks are not used proportionally by all age groups, genders, and socioeconomic groups. This paper explores factors associated with park use by different age and gender groups in low-income neighborhoods in Los Angeles, CA. We found that women's visits to parks generally centered around children, whereas men's visits were more likely to be associated with their own physical activity. Barriers for seniors are associated with limited facilities and programming that meet their needs. Park managers should consider park renovations that include social meeting places, comfortable sitting areas, and walking paths to better serve women and seniors.


Subject(s)
Environment Design , Exercise , Motor Activity , Parks, Recreational/statistics & numerical data , Poverty Areas , Public Facilities , Recreation , Urban Population , Adolescent , Adult , Age Distribution , Aged , Female , Humans , Los Angeles , Male , Middle Aged , Residence Characteristics , Sex Distribution , Social Class , Young Adult
11.
J Urban Health ; 95(6): 881-887, 2018 12.
Article in English | MEDLINE | ID: mdl-30324357

ABSTRACT

Neighborhood parks are important venues for the urban population to do moderate-to-vigorous physical activity in leisure time. Parks can be particularly important for low-income neighborhoods, whose residents suffer from high rates of chronic diseases and may have less access to fee-based fitness exercise facilities. This study assessed the contribution of parks to local populations' physical activity in 48 high-poverty neighborhoods in the city of Los Angeles, using systematic observation of park use and surveys of park users and residents conducted between 2013 and 2015. We found that parks accounted for approximately 2.1% (between-park SD = 1.4%) of moderate physical activity time and 3.1% (between-park SD = 2.1%) of vigorous physical activity time of the local population, both of which were notably lower than the city-level average previously reported. Parks' contribution to physical activity was positively associated with park size (ß = 0.13, p < 0.0001) and negatively associated with poverty (ß = - 0.10, p < 0.0001) and local population density (ß = - 0.25, p = 0.005). Parks in high-poverty neighborhoods in Los Angeles are underutilized, and more efforts are needed to fully realize their potential for population health.


Subject(s)
Environment Design/statistics & numerical data , Exercise , Parks, Recreational/statistics & numerical data , Poverty/statistics & numerical data , Residence Characteristics/statistics & numerical data , Urban Population/statistics & numerical data , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Child , Female , Humans , Los Angeles , Male , Middle Aged , Population Density , Sex Factors , Socioeconomic Factors , Surveys and Questionnaires , Young Adult
12.
Cell Biochem Funct ; 36(7): 366-376, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30264402

ABSTRACT

Even though increasing evidence indicates the importance of peroxisomal lipid metabolism in regulating biological and pathological events, its involvement in cartilage development has not been well studied. Here, we identified the importance of peroxisomal function, particularly the functional integrity of ABCD2, in the pathogenesis of osteoarthritis (OA). Knockdown of ABCD2 in OA chondrocytes induced the accumulation of very long chain fatty acids (VLCFAs) and apoptotic cell death. Moreover, knockdown of ABCD2 altered profiles of miRNAs that affect the expression level of ACSL4, a known direct regulator of lipid metabolism. Suppression of ACSL4 in human chondrocytes-induced VLCFA accumulation, MMP-13 expression, and apoptotic cell death. In vivo morph-down of the ACSL4 homologue in zebrafish resulted in significant defects in cartilage development and in vivo knockdown of ACSL4 in cartilage tissue of an OA model mice promoted severe cartilage degradation. In summary, to the best of our knowledge, this is the first report suggesting that the regulatory network among peroxisomal ABCD2:ACSL4:VLCFA serves as a novel regulator of cartilage homeostasis, and these data may provide novel insights into the role of peroxisomal fatty acid metabolism in pathogenesis of human OA. SIGNIFICANCE OF THE STUDY: Our study indicates that peroxisomal dysfunction is closely related to OA pathogenesis. Particularly, the functional integrity of ABCD2 may play an important role in OA pathogenesis via the accumulation of VLCFAs and stimulation of apoptotic death through altering profiles of miRNAs that target ACSL4. Our findings suggest that targeting the regulatory network among the peroxisomal ABCD2:ACSL4:VLCFA axis may provide a new potential therapeutic strategy for OA pathogenesis.


Subject(s)
ATP Binding Cassette Transporter, Subfamily D/metabolism , Coenzyme A Ligases/metabolism , Lipid Metabolism , MicroRNAs/metabolism , Osteoarthritis/metabolism , ATP Binding Cassette Transporter, Subfamily D/genetics , Adult , Animals , Apoptosis , Chondrocytes/metabolism , Chondrocytes/pathology , Coenzyme A Ligases/genetics , Disease Models, Animal , Fatty Acids/metabolism , Female , Gene Expression Profiling , Humans , Male , Mice , MicroRNAs/genetics , Middle Aged , Osteoarthritis/genetics , Osteoarthritis/pathology , Peroxisomes/metabolism , Zebrafish
14.
Soc Sci Med ; 341: 116544, 2024 01.
Article in English | MEDLINE | ID: mdl-38169181

ABSTRACT

RATIONALE: Despite the existing body of research on the impact of child bereavement, little is known about whether time to the death of an adult child is longitudinally associated with changes in depressive symptoms among older parents. OBJECTIVE: This study examines (a) trajectories of depressive symptoms before and after the loss of an adult child and (b) whether these trajectories differ across parent-child gender dyads (father-son, father-daughter, mother-son, and mother-daughter). METHODS: Using eight waves of the Korean Longitudinal Study of Ageing (KLoSA), this study employs fixed effects models to mitigate potential bias due to unobserved individual-level heterogeneity. Gender-stratified fixed effects models were estimated to investigate potential heterogeneity in the trajectories of depressive symptoms by parent-child gender dyads. RESULTS: The result of this study revealed that depressive symptoms increased within the first year following the loss of an adult child among bereaved parents. Within a year of the loss of a child, both mothers and fathers experienced an increase in depressive symptoms. However, only fathers experienced lasting effects for up to two years. Different patterns in psychological adjustment to bereavement were observed across different parent-child gender dyads. Among daughter-bereaved fathers, depressive symptoms surged within the first year and persisted even beyond the fourth year of loss. In contrast, for other dyads, only an immediate rise in depressive symptoms within the first year of loss was observed. CONCLUSIONS: The loss of an adult child increases the depressive symptoms of parents. This study highlights the importance of considering the different trajectories of psychological adjustment to bereavement, particularly based on parent-child gender dyads, when formulating policies for providing psychological support to older parents who have experienced the loss of their child.


Subject(s)
Depression , Fathers , Male , Female , Adult , Humans , Fathers/psychology , Depression/epidemiology , Longitudinal Studies , Parents/psychology , Mothers/psychology
15.
Disabil Rehabil ; : 1-7, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38557388

ABSTRACT

Purpose: This study aims to estimate (a) the relationship between disability acceptance and depressive symptoms, and (b) how the quality and quantity of social support might moderate the link between disability acceptance and depressive symptoms.Materials and methods: The data for this study included information from 5165 individuals with disability who participated in 3 waves of the Disability and Life Dynamic Panel spanning years 2018 to 2020. This study employed fixed effects models to estimate the association between disability acceptance and depressive symptoms. Interaction models were used to assess the moderating effects of both the quantity and quality of social support.Results: A lower acceptance of disability was positively associated with depressive symptoms. Moreover, both the quantity and quality of social support were associated with a decrease in depressive symptoms. Only the quality of social support played a significant role in moderating the relationship between disability acceptance and depressive symptoms.Conclusion: A lower acceptance of disability increases depressive symptoms in individuals with disabilities. This study underscores the need for interventions to focus on enhancing the quality of social support to mitigate the link between disability acceptance and depressive symptoms.


A lower acceptance of disability is positively associated with depressive symptoms among persons with disability.The association between lower disability acceptance and depressive symptoms attenuates as emotional support from family and friends increases.The number of family and friends does not significantly change the relationship between lower disability acceptance and depressive symptoms.The findings highlight the importance of interventions enhancing quality of social support in order to mitigate the association between disability acceptance and psychological health.

16.
Sci Rep ; 14(1): 21323, 2024 Sep 12.
Article in English | MEDLINE | ID: mdl-39266609

ABSTRACT

Magnetic susceptibility enhancement (kE) is useful for reconstructing terrestrial paleohydroclimate variabilities. However, kE and its driving process(es) in the Korean Peninsula remain uninvestigated. Therefore, this study investigated two kEs of similar magnitudes, dated MIS 1 (Holocene) and late MIS 3 (~ 29-36 ka), from a paleosol sequence in the upland of paleo-fluvial terrace in the central Korean Peninsula. We observed increased ferri- and antiferro-magnetic mineral components,including ultrafine particles, and stronger chlorite weathering for the two kEs, suggesting pedogenic component predominance. The Fe-bearing (phyllo)silicate weathering mechanism proposed for the Chinese Loess Plateau sequences can explain the pedogenesis-induced kEs for the studied site. Superparamagnetic-domain (SPD) to pseudo-single-domain sized particles of pedogenic magnetite are likely major contributors to kEs. Moreover, we recognized the younger kE interval as more SPD contribution but less in total ferrimagnetic contribution, and more antiferromagnetic contribution than the older ones. The magnetic differences between the periods can result from vegetation cover impact and surrounding hydroclimate conditions, consistent with the recent suggestion for part of the southeast Chinese sites with relatively more rainfall. Consequently, our study provides a baseline for improving the relationship between mineral magnetic signals and local/regional hydroclimatic and environmental variabilities.

17.
bioRxiv ; 2024 Sep 08.
Article in English | MEDLINE | ID: mdl-39282261

ABSTRACT

Generation of membrane curvature is fundamental to cellular function. Recent studies have established that the glycocalyx, a sugar-rich polymer layer at the cell surface, can generate membrane curvature. While there have been some theoretical efforts to understand the interplay between the glycocalyx and membrane bending, there remain open questions about how the properties of the glycocalyx affect membrane bending. For example, the relationship between membrane curvature and the density of glycosylated proteins on its surface remains unclear. In this work, we use polymer brush theory to develop a detailed biophysical model of the energetic interactions of the glycocalyx with the membrane. Using this model, we identify the conditions under which the glycocalyx can both generate and sense curvature. Our model predicts that the extent of membrane curvature generated depends on the grafting density of the glycocalyx and the length of the polymers constituting the glycocalyx. Furthermore, when coupled with the intrinsic membrane properties such as spontaneous curvature and a line tension along the membrane, the curvature generation properties of the glycocalyx are enhanced. These predictions were tested experimentally by examining the propensity of glycosylated transmembrane proteins to drive the assembly of highly-curved filopodial protrusions at the plasma membrane of adherent mammalian cells. Our model also predicts that the glycocalyx has curvature-sensing capabilities, in agreement with the results of our experiments. Thus, our study develops a quantitative framework for mapping the properties of the glycocalyx to the curvature generation capability of the membrane.

18.
Obesity (Silver Spring) ; 32(2): 352-362, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38018497

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the role of the follistatin-like 1 (Fstl1) and disco-interacting protein 2 homolog A (DIP2a) axis in relation to lipid metabolism during and after endurance exercise and to elucidate the mechanisms underlying the metabolic effects of Fstl1 on adipocytes, considering its regulation by exercise and muscle mass and its link to obesity. METHODS: Twenty-nine sedentary males participated in endurance exercise, and blood samples were collected during and after the exercise. Body composition, Fstl1, glycerol, epinephrine, growth hormone, and atrial natriuretic peptide were measured. 3T3-L1 adipocytes, with or without DIP2a knockdown, were treated with Fstl1 to assess glycerol release, cyclic AMP/cyclic GMP production, and hormone sensitive lipase phosphorylation. The association between DIP2a gene expression levels in human adipose tissues and exercise-induced lipolysis was examined. RESULTS: Fstl1 levels significantly increased during endurance exercise and following recovery, correlating with lean body mass and lipolysis. In 3T3-L1 adipocytes, Fstl1 increased glycerol release, cyclic GMP production, and hormone sensitive lipase activation, but these effects were attenuated by DIP2a knockdown. DIP2a gene expression in human adipose tissues correlated with serum glycerol concentrations during endurance exercise. CONCLUSIONS: Fstl1 is a myokine facilitating lipid mobilization during and after endurance exercise through DIP2a-mediated lipolytic effects in adipocytes.


Subject(s)
Follistatin-Related Proteins , Follistatin , Humans , Male , Cyclic GMP/metabolism , Follistatin/metabolism , Follistatin-Related Proteins/genetics , Follistatin-Related Proteins/metabolism , Glycerol/metabolism , Lipid Mobilization , Lipolysis/physiology , Myokines , Sterol Esterase/metabolism
19.
Bioresour Technol ; 393: 130158, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38070579

ABSTRACT

Mucic acid holds promise as a platform chemical for bio-based nylon synthesis; however, its biological production encounters challenges including low yield and productivity. In this study, an efficient and high-yield method for mucic acid production was developed by employing genetically engineered Saccharomyces cerevisiae expressing the NAD+-dependent uronate dehydrogenase (udh) gene. To overcome the NAD+ dependency for the conversion of pectin to mucic acid, xylose was utilized as a co-substrate. Through optimization of the udh expression system, the engineered strain achieved a notable output, producing 20 g/L mucic acid with a highest reported productivity of 0.83 g/L-h and a theoretical yield of 0.18 g/g when processing pectin-containing citrus peel waste. These results suggest promising industrial applications for the biological production of mucic acid. Additionally, there is potential to establish a viable bioprocess by harnessing pectin-rich fruit waste alongside xylose-rich cellulosic biomass as raw materials.


Subject(s)
Citrus , Saccharomyces cerevisiae , Sugar Acids , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Xylose/metabolism , Fermentation , Citrus/metabolism , NAD/metabolism , Pectins , Metabolic Engineering/methods
20.
Cell Death Discov ; 10(1): 144, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38491062

ABSTRACT

Particulate matter (PM) is a global environmental hazard, which affects human health through free radical production, cell death induction, and immune responses. PM activates inflammasomes leading to excessive inflammatory responses and induces ferroptosis, a type of cell death. Despite ongoing research on the correlation among PM-induced ferroptosis, immune response, and inflammasomes, the underlying mechanism of this relationship has not been elucidated. In this study, we demonstrated the levels of PM-induced cell death and immune responses in murine macrophages, J774A.1 and RAW264.7, depending on the size and composition of particulate matter. PM2.5, with extraction ions, induced significant levels of cell death and immune responses; it induces lipid peroxidation, iron accumulation, and reactive oxygen species (ROS) production, which characterize ferroptosis. In addition, inflammasome-mediated cell death occurred owing to the excessive activation of inflammatory responses. PM-induced iron accumulation activates ferroptosis and inflammasome formation through ROS production; similar results were observed in vivo. These results suggest that the link between ferroptosis and inflammasome formation induced by PM, especially PM2.5 with extraction ions, is established through the iron-ROS axis. Moreover, this study can effectively facilitate the development of a new therapeutic strategy for PM-induced immune and respiratory diseases.

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