64 research outputs found
PPM1A Controls Diabetic Gene Programming through Directly Dephosphorylating PPAR?? at Ser273
Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a master regulator of adipose tissue biology. In obesity, phosphorylation of PPAR gamma at Ser273 (pSer273) by cyclin-dependent kinase 5 (CDK5)/extracellular signal-regulated kinase (ERK) orchestrates diabetic gene reprogramming via dysregulation of specific gene expression. Although many recent studies have focused on the development of non-classical agonist drugs that inhibit the phosphorylation of PPAR gamma at Ser273, the molecular mechanism of PPAR gamma dephosphorylation at Ser273 is not well characterized. Here, we report that protein phosphatase Mg2+/Mn2+-dependent 1A (PPM1A) is a novel PPAR gamma phosphatase that directly dephosphorylates Ser273 and restores diabetic gene expression which is dysregulated by pSer273. The expression of PPM1A significantly decreases in two models of insulin resistance: diet-induced obese (DIO) mice and db/db mice, in which it negatively correlates with pSer273. Transcriptomic analysis using microarray and genotype-tissue expression (GTEx) data in humans shows positive correlations between PPM1A and most of the genes that are dysregulated by pSer273. These findings suggest that PPM1A dephosphorylates PPAR gamma at Ser273 and represents a potential target for the treatment of obesity-linked metabolic disorders
Chlorin e6 Prevents ADP-Induced Platelet Aggregation by Decreasing PI3K-Akt Phosphorylation and Promoting cAMP Production
A number of reagents that prevent thrombosis have been developed but were found to have serious side effects. Therefore, we sought to identify complementary and alternative medicinal materials that are safe and have long-term efficacy. In the present studies, we have assessed the ability of chlorine e6 (CE6) to inhibit ADP-induced aggregation of rat platelets and elucidated the underlying mechanism. CE6 inhibited platelet aggregation induced by 10â”M ADP in a concentration-dependent manner and decreased intracellular calcium mobilization and granule secretion (i.e., ATP and serotonin release). Western blotting revealed that CE6 strongly inhibited the phosphorylations of PI3K, Akt, c-Jun N-terminal kinase (JNK), and different mitogen-activated protein kinases (MAPKs) including extracellular signal-regulated kinase 1/2 (ERK1/2) as well as p38-MAPK. Our study also demonstrated that CE6 significantly elevated intracellular cAMP levels and decreased thromboxane A2 formation in a concentration-dependent manner. Furthermore, we determined that CE6 initiated the activation of PKA, an effector of cAMP. Taken together, our findings indicate that CE6 may inhibit ADP-induced platelet activation by elevating cAMP levels and suppressing PI3K/Akt activity. Finally, these results suggest that CE6 could be developed as therapeutic agent that helps prevent thrombosis and ischemia
Clinical Significance of Crescent Formation in IgA Nephropathy â a Multicenter Validation Study
Background/Aims: Additional validation study was warranted to confirm the clinical significance of C score, which was recently added to the Oxford classification for immunoglobulin A nephropathy (IgAN). Methods: We performed a multicenter retrospective cohort study in four hospitals in Korea. Patients who had biopsied glomeruli less than eight or inadequate follow-up information were excluded. Clinicopathologic parameters, including the degree of cellular or fibrocellular crescents, were collected and included in multivariable models for Cox regression analysis. The main outcome was a composite renal outcome, defined as a merge of progression to end-stage renal disease (ESRD) and halving of estimated glomerular filtration rate (eGFR) from baseline. Results: Among included 3,380 biopsy-confirmed IgAN patients, there were 664 (19.6%) patients with C1 and 60 (1.8%) patients with C2 scores in the study population. Although C0 and C1 patients shared similar baseline characteristics, C2 patients frequently had more clinicopathologic risk factors for poor prognosis of IgAN. Both C1 [adjusted HR 1.33 (1.11-1.58), P=0.002] and C2 [adjusted HR 2.24 (1.46-3.43), P< 0.001] scores were associated with an increased risk of the composite outcome. C2 was a strong predictive parameter associated with both progression to ESRD and halving of eGFR, whereas C1 was mainly associated with the increased risk of halving of eGFR. Notably, the proportion of crescent showed a linear association with the risk of adverse renal outcome. Conclusion: The C score in the Oxford classification is a valid predictive parameter for IgAN prognosis. Additional clinical attention is necessary for IgAN patients with identified cellular or fibrocellular crescents
Mineral bone disorder in children with chronic kidney disease: Data from the KNOW-Ped CKD (Korean cohort study for outcome in patients with pediatric chronic kidney disease) study
BackgroundChildren with chronic kidney disease (CKD) are at high risk of mineral bone disorder (MBD), which leads to fractures, growth retardation, and cardiovascular disease. We aimed to comprehensively understand the relationship between renal function and factors related to MBD and evaluate the prevalence and distribution characteristics of MBD, specifically among Korean patients from the KNOW-PedCKD cohort.MethodsFrom the baseline data of the KNOW-PedCKD cohort, we examined the prevalence and distribution of MBD in 431 Korean pediatric CKD patients, including the level of corrected total calcium, serum phosphate, serum alkaline phosphatase, serum intact parathyroid hormone (iPTH), fibroblast growth factor 23 (FGF-23), serum vitamin D, fractional excretion of phosphate (FEP), and bone densitometry Z-scores.ResultsThe median serum calcium level remained relatively normal regardless of the CKD stage. The levels of 1,25-dihydroxy vitamin D, urine calcium-to-creatinine ratio, and bone densitometry Z-score significantly decreased with advancing CKD stage, while those of serum phosphate, FGF-23, and FEP significantly increased with CKD stage. The prevalence of hyperphosphatemia (17.4%, 23.7%, and 41.2% from CKD stages 3b, 4, and 5, respectively) and hyperparathyroidism (37.3%, 57.4%, 55.3%, and 52.9% from CKD stages 3a, 3b, 4, and 5, respectively) significantly increased with the CKD stage. Prescriptions of medications, such as calcium supplements (39.1%, 42.1%, 82.4%), phosphate binders (39.1%, 43.4%, 82.4%), and active vitamin D (21.7%, 44.7%, and 64.7%) significantly increased with CKD stage 3b, 4, and 5, respectively.ConclusionsThe results demonstrated the prevalence and relationship of abnormal mineral metabolism and bone growth according to CKD stage in Korean pediatric CKD patients for the first time
Corrigendum: Mineral bone disorder in children with chronic kidney disease: data from the KNOW-Ped CKD (Korean cohort study for outcome in patients with pediatric chronic kidney disease) study
Baseline characteristics of the Korean genetic cohort of inherited cystic kidney disease
Background Identifying genetic mutations in individuals with inherited cystic kidney disease is necessary for precise treatment. We aimed to elucidate the genetic characteristics of cystic kidney disease in the Korean population. Methods We conducted a 3-year prospective, multicenter cohort study at eight hospitals from May 2019 to May 2022. Patients with more than three renal cysts were enrolled and classified into two categories, typical autosomal dominant polycystic kidney disease (ADPKD) and atypical PKD. We identified the clinical characteristics and performed a genetic analysis using a targeted gene panel. Results A total of 725 adult patients were included in the study, of which 560 (77.2%) were diagnosed with typical ADPKD and 165 (22.8%) had atypical PKD. Among the typical ADPKD cases, the Mayo imaging classification was as follows: 1A (55, 9.9%), 1B (149, 26.6%), 1C (198, 35.8%), 1D (90, 16.3%), and 1E (61, 11.0%). The atypical PKD cases were classified as bilateral cystic with bilateral atrophic (31, 37.3%), lopsided (27, 32.5%), unilateral (nine, 10.8%), segmental (eight, 9.6%), bilateral cystic with unilateral atrophic (seven, 8.4%), and asymmetric (one, 1.2%). Pathogenic variants were found in 64.3% of the patients using the ciliopathy-related targeted gene panel. The typical ADPKD group demonstrated a higher discovery rate (62.3%) than the atypical PKD group (41.8%). Conclusion We present a nationwide genetic cohortâs baseline clinical and genetic characteristics for Korean cystic kidney disease
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THE SIGNIFICANCE OF AWE FOR CONSUMER BEHAVIOR
The current research focuses on the transformative emotional experience of awe and its effect on consumersâ behavior. Chapter one (1) delineates how feelings of awe are defined, (2) identifies the affective, psychophysiological, and cognitive consequences of awe, (3) discusses how awe is elicited by practitioners, and (4) reviews current academic investigations of awe experiences in consumer behavior. Contrary to the existing awe research that focuses mostly on virtuous or constructive consumer behaviors, chapter two demonstrates that experiencing awe stimulates a preference for uncommon or beyond-ordinary choices that are uncomfortable, unfamiliar, or unethical (i.e., extraordinary choice). The chapter suggests awe as a novel means to ease burdens of presenting beyond-ordinary consumption options by practitioners. Chapter three demonstrates general conclusion, implications, limitations, and future directions of chapter one and two
Photoelectrochemical Fuel Production on Delafossite AgRhO2 and AgFeO2 and Electrochemical Oxidative Etching of Sn-doped Bi2Te2Se
Correlating electrochemical and photoelectrochemical behaviors to the materials properties is an important aspect to provide basic understanding in diverse scientific fields that employ (photo)electrochemistry. Among different fields, solar fuel generation is a fascinating method to utilize solar energy to produce fuels, thus alleviating potential energy shortage and concerns on climate change. However, there is still a lack of knowledge on the detailed mechanisms for heterogeneous charge transfer processes (CO2 and H2O reduction) and the effect of the catalystsâ chemical and physical properties.
Inspired by previously reported CuRhO2 and CuFeO2 from the Bocarsly and Cava groups, AgRhO2 and AgFeO2 were prepared and examined for their photocatalytic activities. AgRhO2 photocathode was shown to be photocatalytically active for H2 generation with great photostability. However, AgFeO2 did not possess a suitable conduction band edge position, only providing ~130 mV of overpotential for H2 generation and not sufficient for CO2 reduction to formic acid.
The correlation between chemical compositions and photocatalytic activities was examined by comparing AgFeO2, AgRhO2, CuFeO2, and CuRhO2. It was rationalized that Ag+ (instead of Cu+) in the A-site of the delafossite structure (ABO2) reduces the kinetic barrier for H2 generation, and Fe3+ (instead of Rh3+) in the B-site provides a better catalytic surface for both H2 generation and CO2 reduction.
In this thesis, the effect on bulk properties and topological surface states of topological insulators against electrochemical oxidation was also investigated. With potential usage in spintronics and quantum computing, this should be well-understood for future device applications. The electrochemical treatment resulted in triangular etch pits on the surface, but the bulk properties and topological surface states were unaffected. This proved that electrochemical oxidation is a potential method for altering the surface morphology while maintaining the bulk properties and topological surface states
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