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Fabrication of versatile hydrogels in a facile and effective manner represents a pivotal challenge in the field of biomaterials. Herein, a novel strategy is presented for preparing on‐demand degradable hydrogels with multilevel responsiveness. By employing selenol‐dichlorotetrazine nucleophilic aromatic substitution (SNAr) to synthesize hydrogels under mild conditions in a buffer solution, the necessity of additives or posttreatments can be obviated. The nucleophilic and redox reactions between selenol and tetrazine culminate in the formation of three degradable chemical bonds—diselenide, aryl selenide, and dearomatized selenide—in a single, expeditious step. The resultant hydrogel manifests exceptional adaptability to intricate environments in conjunction with self‐healing and on‐demand degradation properties. Furthermore, the resulting material demonstrated light‐triggered antibacterial activity. Animal studies further underscore the potential of integrating metformin into Se‐Tz hydrogels under green light irradiation, as it effectively stimulates angiogenesis and collagen deposition, thereby fostering efficient wound healing. In comparison to previously documented hydrogels, Se‐Tz hydrogels exhibit controlled degradation and drug release, outstanding antibacterial activity, mechanical robustness, and bioactivity, all without the need for costly and intricate preparation procedures. These findings underscore Se‐Tz hydrogels as a safe and effective therapeutic option for diabetic wound dressings. [ABSTRACT FROM AUTHOR]

Background: Lower limb swelling after total knee arthroplasty (TKA) hinders surgical effectiveness. The poor results of studies on swelling interventions are due to the lack of a classification of swelling causes through appropriate medical tests. A gold standard is missing. This study aimed to clarify the causes of TKA postoperative swelling and how to identify them through indicators and medical tests by consulting a wide range of experts from multiple disciplines. Method: The Delphi method was used. A first draft of the index was prepared based on a systematic search of the literature. A total of 11 experts from several disciplines were invited to evaluate the rationality of the indicators and suggest modifications. After two rounds of consultation, the experts reached a consensus, and the consultation was stopped. Results: The response rate of the 11 experts was 100%, and the authoritative Cr was 0.896. Kendall's W values for opinion coordination of the two rounds of consultation were 0.262 and 0.226, respectively (P < 0.001). Among the final indicators, there were 4 primary indicators for swelling cause classification (inflammatory response, poor venous return, joint hematoma, muscle damage, and healing), 19 secondary and 19 tertiary indicators. Conclusion: The indications obtained by systematic literature review and multidisciplinary expert consultation are reliable and scientific. Multiple causes of lower extremity swelling after TKA were identified. Blood test indicators can reflect an inflammatory response, suggest poor venous return, and reflect muscle damage and healing progress. Ultrasound scans are needed to identify underlying thrombotic or valvular problems, joint hematomas, and muscle damage. These tests help clinicians and researchers determine the cause of swelling after TKA and take appropriate management. [ABSTRACT FROM AUTHOR]

Background: Lower limb swelling after total knee arthroplasty (TKA) hinders surgical effectiveness. The poor results of studies on swelling interventions are due to the lack of a classification of swelling causes through appropriate medical tests. A gold standard is missing. This study aimed to clarify the causes of TKA postoperative swelling and how to identify them through indicators and medical tests by consulting a wide range of experts from multiple disciplines. Method: The Delphi method was used. A first draft of the index was prepared based on a systematic search of the literature. A total of 11 experts from several disciplines were invited to evaluate the rationality of the indicators and suggest modifications. After two rounds of consultation, the experts reached a consensus, and the consultation was stopped. Results: The response rate of the 11 experts was 100%, and the authoritative Cr was 0.896. Kendall's W values for opinion coordination of the two rounds of consultation were 0.262 and 0.226, respectively (P < 0.001). Among the final indicators, there were 4 primary indicators for swelling cause classification (inflammatory response, poor venous return, joint hematoma, muscle damage, and healing), 19 secondary and 19 tertiary indicators. Conclusion: The indications obtained by systematic literature review and multidisciplinary expert consultation are reliable and scientific. Multiple causes of lower extremity swelling after TKA were identified. Blood test indicators can reflect an inflammatory response, suggest poor venous return, and reflect muscle damage and healing progress. Ultrasound scans are needed to identify underlying thrombotic or valvular problems, joint hematomas, and muscle damage. These tests help clinicians and researchers determine the cause of swelling after TKA and take appropriate management. [ABSTRACT FROM AUTHOR]

Aim: To analyze the causes, clinical manifestations, diagnosis and treatment of uterine arteriovenous fistula (UAVF). Methods: We retrospectively analyzed 13 patients with UAVF admitted to our hospital from October 2016 to April 2019. Results: All patients had a history of intrauterine surgery (curettage for abortion, artificial removal of placenta, hysteroscopy, diagnostic curettage and intrauterine device removal). The main clinical manifestation of UAVF is paroxysmal massive vaginal bleeding; this involved a massive gush of vaginal blood that stopped suddenly. Sonographic images with typical features of UAVF were observed for 12 patients. Pelvic contrast‐enhanced magnetic resonance imaging was performed as a noninvasive adjuvant examination method for diagnosis. Twelve patients underwent uterine arteriography and a diagnosis of UAVF was confirmed. Then, bilateral uterine artery embolization (UAE) was performed. One patient underwent laparoscopic hysterectomy directly instead of uterine arteriography because of unstable vital signs and one patient underwent laparoscopic hysterectomy 25 weeks after the second UAE. The median time until menstrual recovery was 33 days (range, 20–70 days) after UAE. The median time until normal ultrasound examination results was 10 weeks (range, 2–35 weeks). Conclusion: Acquired UAVF was associated with a history of previous intrauterine surgery. The ultrasound examination and pelvic contrast‐enhanced MRI were noninvasive adjuvant examination method to effectively assist in diagnosis. Uterine arteriography is considered the gold standard for the diagnosis of UAVF, and UAE is considered an effective intervention for treating UAVF and maintaining reproductive function with less damage. Hysterectomy is an appropriate option when conservative measures have failed to prevent a life‐threatening hemorrhage. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to assess the efficacy of canine umbilical cord mesenchymal stem cells (UC-MSCs) on the treatment of knee osteoarthritis in dogs. Methods. Eight dogs were evenly assigned to two groups. The canine model of knee osteoarthritis was established by surgical manipulation of knee articular cartilage on these eight dogs. UC-MSCs were isolated from umbilical cord Wharton’s jelly by 0.1% type collagenase I and identified by immunofluorescence staining and adipogenic and osteogenic differentiation in vitro. A suspension of allogeneic UC-MSCs (1 × 106) and an equal amount of physiological saline was injected into the cavitas articularis in the treated and untreated control groups, respectively, on days 1 and 3 posttreatment. The structure of the canine knee joint was observed by magnetic resonance imaging (MRI), B-mode ultrasonography, and X-ray imaging at the 3rd, 7th, 14th, and 28th days after treatment. Concurrently, the levels of IL-6, IL-7, and TNF-α in the blood of the examined dogs were measured. Moreover, the recovery of cartilage and patella surface in the treated group and untreated group was compared using a scanning electron microscope (SEM) after a 35-day treatment. Results. Results revealed that the isolated cells were UC-MSCs, because they were positive for CD44 and negative for CD34 surface markers, and the cells were differentiated into adipocytes and osteoblasts. Imaging technology showed that as treatment time increased, the high signal in the MRI T2-weighted images decreased, the echo-free space in B ultrasonography images disappeared basically, and the continuous linear hypoechoic region at the trochlear sulcus thickened. On X-ray images, the serrate defect at the ventral cortex of the patella improved, and the low-density gap of the ventral patella and trochlear crest gradually increased in the treated group. On the contrary, the high signal in the MRI T2-weighted images and the echo-free space in B ultrasonography images still increased after a 14-day treatment in the untreated control group, and the linear hypoechoic region was discontinuous. On the X-ray images, there was no improvement in the serrate defect of the ventral cortex of the patella. Results for inflammatory factors showed that the blood levels of IL-6, IL-7, and TNF-α of the untreated control group were significantly higher than those of the treated group (P<0.05) 7–14 days posttreatment. The result of SEM showed that the cartilage neogenesis in the treated group had visible neonatal tissue and more irregular arrangement of new tissue fibers than that of the untreated control group. Furthermore, more vacuoles but without collagen fibers were observed in the cartilage of the untreated control group, and the thickness of the neogenetic cartilage in the treated group (65.13 ± 5.29, 65.30 ± 5.83) and the untreated control group (34.27 ± 5.42) showed a significant difference (P<0.01). Conclusion. Significantly higher improvement in cartilage neogenesis and recovery was observed in the treated group compared to the untreated control group. The joint fluid and the inflammatory response in the treated group decreased. Moreover, improved recovery in the neogenetic cartilage, damaged skin fascia, and muscle tissue around the joints was more significant in the treated group than in the untreated control group. In conclusion, canine UC-MSCs promote the repair of cartilage and patella injury in osteoarthritis, improve the healing of the surrounding tissues, and reduce the inflammatory response. [ABSTRACT FROM AUTHOR]

C15H14Cl2FNO3, triclinic, P¯1 (no. 2), a=8.5995(8) Å, b=9.9579(9) Å, c=10.1418(10) Å, α=113.4900(10)°, β= 95.8730(10)°, γ=96.1610(10)°, V =781.81(13) Å3, Z =2, Rgt(F)=0.0282, wRref(F2)=0.0788, T=100(2)K. [ABSTRACT FROM AUTHOR]

Accelerated repeated-measures degradation tests (ARMDTs) take measurements of degradation or performance on a sample of units over time. In certain products, measurements are destructive, leading to accelerated destructive degradation test (ADDT) data. For example, the test of an adhesive bond needs to break the test specimen to measure the strength of the bond. Lognormal and Weibull distributions are often used to describe the distribution of product characteristics in life and degradation tests. When the distribution is misspecified, the lifetime quantile, often of interest to the practitioner, may differ significantly between these two distributions. In this study, under a specific ADDT, we investigate the bias and variance due to distribution misspecification. We suggest robust test plans under the criteria of minimizing the approximate mean square error. [ABSTRACT FROM PUBLISHER]

OBJECTIVE--Recently, several drugs have been shown to exert beneficial effects for metabolic syndrome through mild regulation of mitochondrial function. Hence, we explored a strategy of targeting mitochondrial function to improve glucose and lipid metabolism. RESEARCH DESIGN AND METHODS--Mitochondrial membrane potential (ΔΨm) is a marker of mitochondrial function; therefore, we set up a high-throughput screening assay of ΔΨm in L6 myotubes. The effects of a selected lead compound were investigated in vitro and in vivo in relation to metabolic syndrome. RESULTS--A novel small-molecule compound, C1, was identified through this high-throughput screening. C1 depolarized ΔΨm in L6 myotubes without cytotoxicity and led to increased cellular AMP-to-ATP ratio, activation of AMP-activated protein kinase (AMPK), and enhanced glucose uptake. It also stimulated the AMPK pathway in HepG2 cells, leading to decreased lipid content. Intriguingly, C1 inhibited respiration in L6 myotubes but did not affect respiration in isolated muscle mitochondria, suggesting that it may depolarize ΔΨm indirectly by affecting the supply of electron donors. Acute administration of C1 in C57BL/6J mice markedly increased fat oxidation and the phosphorylation of AMPK and acetyl-CoA carboxylase in the liver. In diabetic db/db mice, chronic administration of C1 significantly reduced hyperglycemia, plasma fatty acids, glucose intolerance, and the mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase in the liver. CONCLUSIONS--Our results demonstrate a novel small molecule that mildly depolarizes ΔΨm and is able to improve glucose and lipid metabolism to exert beneficial effects for metabolic syndrome. These findings suggest that compounds regulating mitochondrial function may have therapeutic potential for type 2 diabetes. Diabetes 59:256-265, 2010 [ABSTRACT FROM AUTHOR]

Aim: We present two cases of triplet pregnancy with complete hydatidiform mole (CHM) in contrasting outcomes and discuss the complications of mothers and outcomes of fetuses through a literature review, raising an important issue on the management of this special pregnancy. Methods: We share our manage experience for two cases of triplet pregnancy with CHM and retrospectively analyze 18 similar pregnancies reported previously with different pregnancy outcomes. Results: In our cases, one case receiving Clomiphene ovulation induction delivered two live fetuses by cesarean section at 30+ weeks without GTN (gestational trophoblastic neoplasia), unfortunately, the other case following ICSI‐ET terminated the pregnancy in the setting of complications at 18+ weeks without GTN. No severe complications were detected during pregnancy and no pGTD was developed after delivery in neither of the pregnant. Conclusions: Co‐existing complete hydatidiform mole in multiple pregnancies may become more common owing to the spreading use of ART. The decision for whether continue pregnancy depending on the personalized conditions including the complications of the pregnancy, the outcomes of the fetuses, the gestational age for delivery, and the potential progression of persistent gestational trophoblastic disease (pGTD). Furthermore, close monitor is necessary for the pregnant with triplet pregnancy with CHM who want to continue pregnancy. [ABSTRACT FROM AUTHOR]

Microplastics are an emerging hazard in the marine environment, and considered to eventually sink into sediments. An investigation into the long-term variation of microplastic accumulation in sediment cores is essential for understanding the historical trend of this contamination and its response to human activities. In this study, the multidecadal changes of microplastic abundances in two sediment cores from the inner shelf of the East China Sea (ECS) were revealed by two methods, i.e., a visual enumeration method based on scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and a quantitative method based on microplastic-derived carbon (MPC) abundances. The features of microplastics were determined via SEM-EDS and micro-Fourier transform infrared spectroscopy (μ-FTIR). The results reveal a multidecadal increasing trend of microplastic accumulation in the coastal sediments of the ECS since the 1960s, which may be jointly governed by the release of plastic wastes and oceanographic dynamics. Meanwhile, the breakpoint of the exponential growth of microplastics in the ECS occurs in 2000 AD, which well matches the rapid increasing of plastic production and consumption in China. Further, based on the MPC contents in sediments, the influence of microplastics on the quantitative evaluation of carbon storage in the ECS has been examined for the first time, revealing an insignificant (<2% before 2014 AD) but potentially-increasing (6.8% by 2025 AD) contribution of microplastics to carbon burial. Our results may provide the important data for evaluating and mitigating the impact of microplastics on the marine environment. Image 1 • A multidecadal increasing trend of microplastic accumulation was revealed in sediment cores in the ECS since the 1960s. • High abundances of microplastics were detected in the form of fragments with the prevalent size of <100 μm. • Microplastic accumulation in sediments in the ECS is associated with Chinese plastic production and consumption. • Microplastics have made an insignificant but potentially-increasing contribution to sedimentary carbon storage in the ECS. [ABSTRACT FROM AUTHOR]

Microplastic pollution in marine environments is of particular concern on its risk to the ecosystem. To assess and manage microplastic contaminants, their quantitative detection in environmental samples is a high priority. However, uncertainties of current methods still exist when estimating their abundances, particularly with fine-grained (<1 mm) microplastics. This work reports a novel thermoanalytical method for quantifying microplastics by measuring the contents of microplastic-derived carbon (MPC) in samples under the premise of nearly eliminating the limit of their particle appearances. After validating the method via samples with the spiked microplastics, we have conducted a case study on sediment core H43 that spanned 1925–2009 CE from the Yellow Sea for further illustrating the high reliability and practicability of this method for quantifying microplastics in natural samples. Our results have demonstrated that the proposed method may be a promising technique to determine the mass-related concentrations of the total microplastics in marine sediments for evaluating their pollution status and quantitative contribution to marine carbon storage. Unlabelled Image • A new method for quantifying microplastics was developed via analyzing MPC contents in sediments. • The method works independently of particle appearances. • The method was employed to reveal the multidecadal record of microplastic pollution in the Yellow Sea. • A microplastic contribution to sedimentary carbon storage was evaluated using this method. [ABSTRACT FROM AUTHOR]

The bacterial diseases of tilapia caused by Streptococcus agalactiae have resulted in the high mortality and huge economic loss in the tilapia industry. Matrix metalloproteinase-9 (MMP-9) may play an important role in fighting infection. However, the role of MMP-9 in Nile tilapia against S. agalactiae is still unclear. In this work, MMP-9 cDNA of Nile tilapia (NtMMP-9) has been cloned and characterized. NtMMP-9 has 2043 bp and encodes a putative protein of 680 amino acids. NtMMP-9 contains the conserved domains interacting with decorin and inhibitors via binding forces compared to those in other teleosts. Quantitative real-time-polymerase chain reaction (qPCR) analysis reveals that NtMMP-9 distinctly upregulated following S. agalactiae infection in a tissue- and time-dependent response pattern, and the tissues, including liver, spleen, and intestines, are the major organs against a S. agalactiae infection. Besides, the proteolytic activity of NtMMP-9 is also confirmed by heterologous expression and zymography, which proves the active function of NtMMP-9 interacting with other factors. The findings indicate that NtMMP-9 was involved in immune responses against the bacterial challenge at the transcriptional level. Further work will focus on the molecular mechanisms of NtMMP-9 to respond and modulate the signaling pathways in Nile tilapia against S. agalactiae invasion and the development of NtMMP-9-related predictive biomarkers or vaccines for preventing bacterial infection in the tilapia industry. [ABSTRACT FROM AUTHOR]

NR4A1 (NUR77) is an orphan nuclear receptor that has been implicated in both cell survival and apoptosis. However, the role of NUR77 in trophoblast function during early placenta development has not been fully elucidated. In this study, we showed that NUR77 expression was significantly lower in the villi of the recurrent miscarriage (RM) group compared to that in the healthy controls (HCs) group. We used immunohistochemistry and found that NUR77 was highly expressed in human placental villi during early pregnancy, especially in syncytiotrophoblast (STB), and was expressed at a much lower level in STB from the RM group than in those from HC group. Western blotting data further confirmed that NUR77 was highly expressed in primary human term placental STB and the FSK-induced BeWo cell line. Moreover, antibody array screening and ELISA revealed that NUR77 promoted significant placental growth factor (PGF) expression during trophoblast fusion. Ectopic overexpression and knockdown experiments demonstrated that PGF was a novel downstream target of NUR77, and serum PGF expression correlated positively with trophoblast NUR77 mRNA levels in HCs and RM patients. Importantly, bioinformatics analysis identified two NUR77 binding sites in the PGF promoter region, and chromatin immunoprecipitation (ChIP) coupled with Western blotting analysis further verified that NUR77 bound directly to the PGF promoter region and promoted PGF expression. Furthermore, in a BeWo/HTR-8 co-culture system, FSK-induced BeWo-secreted PGF promoted HTR-8 cell migration and invasion, and an anti-PGF antibody reversed this effect. Collectively, these results indicated that NUR77 may play a key role in regulating trophoblast invasion at early pregnancy. Key messages: NUR77 expression was significantly decreased in the syncytiotrophoblast of the recurrent miscarriage group compared to that in the healthy control group. NUR77 promoted PGF expression during trophoblast fusion. ChIP and western blotting experiments verified that NUR77 bound directly to the PGF promoter region and activated PGF expression in trophoblast. Trophoblast-derived PGF promoted HTR-8 cell migration and invasion in a cell co-culture system. [ABSTRACT FROM AUTHOR]

Cyclooxygenase-2 (COX-2) is regulated post-transcriptionally by the AU-rich element (ARE) in the 3′-untranslated region (UTR) of its mRNA. However, the mechanism of COX-2 induction in infertility has not been thoroughly elucidated to date. The aim of this study was to examine the association between COX-2 and fragile X-related protein 1 (FXR1) in trophoblasts. Using quantitative reverse transcription polymerase chain reaction, our results showed that FXR1 mRNA expression levels were significantly decreased in trophoblasts from recurrent miscarriage patients compared with healthy controls; conversely, COX - 2 mRNA expression levels were increased in patient samples. We also observed that FXR1 was highly expressed in human placental villi during early pregnancy. Furthermore, we used western blotting and immunofluorescence to analyse the expression levels of FXR1 and COX-2 in HTR-8 cells that were treated with tumour necrosis factor α; we observed that the expression of COX-2 was clearly increased in HTR-8 cells treated with FXR1 small interfering RNA, whereas the expression of COX-2 was effectively decreased in HTR-8 cells with FXR1 overexpressed via a plasmid. Importantly, bioinformatics analysis identified FXR1 binding sites in the 3′-UTR region of COX-2 and firefly luciferase reporter assay analysis verified that FXR1 binds directly to the 3′-UTR region of COX-2. ELISA assays showed that overexpression of FXR1 enhanced vascular endothelial growth factor-A and interleukin-8 expression in HTR-8 cells, whereas conversely, knockdown of FXR1 effectively repressed these effects. In conclusion, the results of this study indicate that FXR1 is a novel COX-2 regulatory factor. Fragile X-related protein 1 (FXR1) regulates the stability of multiple targets that have important biological roles. However, the role of FXR1 in trophoblasts at the maternal–fetal interface remains poorly understood. Our findings identify a novel function for FXR1 in trophoblasts via destabilisation of COX-2 mRNA. This study reveals a new pathway governing the regulation of FXR1 and COX-2 in trophoblast function during early pregnancy. [ABSTRACT FROM AUTHOR]

The new gelatin-based protein hydrogel has excellent mechanical properties, porosity, biodegradability and good adhesion. The incorporation of bone marrow mesenchymal stem cell (BMSC)-derived nanovesicles (NV) confers antioxidant, angiogenic, anti-inflammatory proliferation-promoting activity to the hydrogel at the wound site, which greatly promotes the healing of diabetic wounds. [Display omitted] The application of gelatin hydrogels is hampered by their poor mechanical properties, which are unfavorable for debridement and diabetic wound healing. Herein, bovine serum albumin (BSA)-bridged gelatin hydrogels biopotentiated by bone marrow mesenchymal stem cell (BMSC)-derived nanovesicles (NV), named NV@BSA-GEL, were fabricated by reinforcement of gelatin hydrogels with genipin and BSA in a one-pot, low-cost green approach based on amide bonding-guided crosslinking. Genipin introduction endowed the crosslinking of gelatin hydrogels with weak mechanical properties that were reinforced by BSA bridging to realize suitable mechanical properties for wound dressing, including excellent flexibility and appropriate rigidity. The bioactivity of NV released by the hydrogels resulted in efficient ROS scavenging and favorable immunomodulatory activity as well as promoted cell proliferation and migration of fibroblasts and vascular endothelial cells. Proteomic analysis confirmed that NV harbors a variety of growth factors that can promote wound healing. In vivo , the NV@BSA-GEL hydrogel had superior wound healing effects compared to BSA-GEL, including faster wound healing, stimulation of angiogenesis, contributing to an anti-inflammatory extracellular matrix, and promoting skin maturation, with no systemic toxicity. Thus, the combined merits of NV@BSA-GEL suggest that it has high potential as a new hydrogel dressing for the safe and efficient treatment of diabetic wounds. [ABSTRACT FROM AUTHOR]

Brain size varies dramatically between vertebrate species. Two prominent adaptive hypotheses - the Cognitive Buffer Hypothesis (CBH) and the Expensive Brain Hypothesis (EBH) - have been proposed to explain brain size evolution. The CBH assumes that brain size should increase with seasonality, as the cognitive benefits of a larger brain should help overcoming periods of food scarcity via, for example, increased behavioral flexibility. Alternatively, the EBH states that brain size should decrease with seasonality because a smaller brain confers energetic benefits in periods of food scarcity. Here, to test the two adaptive hypotheses by studying the effects of variation in temperature and growth season on variations in overall brain size and the size of specific brain regions (viz. olfactory nerves, olfactory bulbs, telencephalon, optic tectum and cerebellum) among Hylarana guentheri populations. Inconsistent with the predictions of both the EBH and the CBH, variation in temperature and growth season did not exhibit correlations with overall brain size and the size of brain regions across populations. Hence, our data do not provide support for either the EBH or the CBH to explain brain size variation in H. guentheri. Furthermore, brain size variation did not differ between males and females in this species. Our findings suggest that both the variation in temperature and growth season did not shape the variation in brain size in H. guentheri. [ABSTRACT FROM AUTHOR]

A detailed study of the M3N4 (, Ge, Sn) nitrides in their tetragonal, monoclinic and orthorhombic phases has been performed with the plane-wave pseudo-potential method combined with the quasi-harmonic approximation, including the phononic effects. We rationalize the main puzzle, i.e., the fundamental properties of these phases are unclear, by calculating the crystal structures, density of states, and optical properties. The direct band gaps of t-Ge3N4, m-Si3N4, and o-Ge3N4 benefit the opto–electrical properties. t-, m-, and o-Si3N4 can be used as refractive materials while m-M3N4 (, Ge, Sn) are optically transparent in the visible light region. Our results improve the understanding of the detailed electronic structures of all compounds, as well as the influences of electronic structure on their stabilities. Furthermore, we find that thermodynamic quantities are sensitive to structures and, therefore, depend on various temperature and pressure conditions. [ABSTRACT FROM AUTHOR]

Abstract: AMP-activated protein kinase (AMPK), which is a pivotal guardian of whole-body energy metabolism, has become an attractive therapeutic target for metabolic syndrome. Previously, using a homogeneous scintillation proximity assay, we identified the small-molecule AMPK activator C24 from an optimization based on the original allosteric activator PT1. In this paper, the AMPK activation mechanism of C24 and its potential beneficial effects on glucose and lipid metabolism on db/db mice were investigated. C24 allosterically stimulated inactive AMPK α subunit truncations and activated AMPK heterotrimers by antagonizing autoinhibition. In primary hepatocytes, C24 increased the phosphorylation of AMPK downstream target acetyl-CoA carboxylase dose-dependently without changing intracellular AMP/ATP ratio, indicating its allosteric activation in cells. Through activating AMPK, C24 decreased glucose output by down-regulating mRNA levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) in primary hepatocytes. C24 also decreased the triglyceride and cholesterol contents in HepG2 cells. Due to its improved bioavailability, chronic oral treatment with multiple doses of C24 significantly reduced blood glucose and lipid levels in plasma, and improved the glucose tolerance of diabetic db/db mice. The hepatic transcriptional levels of PEPCK and G6Pase were reduced. These results demonstrate that this orally effective activator of AMPK represents a novel approach to the treatment of metabolic syndrome. [Copyright &y& Elsevier]

AMP-activated protein kinase (AMPK) is an energy sensor of metabolism that is an attractive therapeutic target for type 2 diabetes mellitus and metabolic syndrome. Using a homogeneous scintillation proximity assay (SPA), we identified a new small-molecule AMPK activator, ZLN024, which allosterically stimulated active AMPK heterotrimers and the inactive α1 subunit truncations α1 (1–394) and α1 (1–335) but not α1 (1–312). AMPK activation by ZLN024 requires the pre-phosphorylation of Thr-172 by at least one upstream kinase and protects AMPK Thr-172 against dephosphorylation by PP2Cα. ZLN024 activated AMPK in L6 myotubes and stimulated glucose uptake and fatty acid oxidation without increasing the ADP/ATP ratio. ZLN024 also activated AMPK in primary hepatocytes, decreased fatty acid synthesis and glucose output. Treatment of db/db mice with 15 mg/kg/day ZLN024 improved glucose tolerance; liver tissue weight, triacylglycerol and the total cholesterol content were decreased. The hepatic transcriptional level of G6Pase, FAS and mtGPAT were reduced. The transcription of genes involved in fatty acid oxidation and the mitochondrial biogenesis of muscle tissue were elevated. The ACC phosphorylation was increased in muscle and liver. This study provides a novel allosteric AMPK activator for functional study in vitro and in vivo and demonstrates that AMPK allosteric activators could be a promising therapeutic approach for type 2 diabetes mellitus and metabolic syndrome. [ABSTRACT FROM AUTHOR]

Caspase-3 is an attractive therapeutic target for treatment of diseases involving disregulated apoptosis. We report here the mechanism of caspase-3 inactivation by isoquinoline- 1,3,4-trione derivatives. Kinetic analysis indicates the compounds can irreversibly inactivate caspase-3 in a 1,4-dithiothreitol (DTT)- and oxygen-dependent manner, implying that a redox cycle might take place in the inactivation process. Reactive oxygen species detection experiments using a chemical indicator, together with electron spin resonance measurement, suggest that ROS can be generated by reaction of isoquinoline-1,3,4-trione derivatives with DTT. Oxygen-free radical scavenger catalase and superoxide dismutase eliciting the inactivation of caspase-3 by the inhibitors confirm that ROS mediates the inactivation process. Crystal structures of caspase-3 in complexes with isoquinoline-1,3,4-trione derivatives show that the catalytic cysteine is oxidized to sulfonic acid (-SO3H) and isoquinoline-1,3,4-trione derivatives are bound at the dimer interface of caspase-3. Further mutagenesis study shows that the binding of the inhibitors with caspase-3 appears to be nonspecific. Isoquinoline-1,3,4-trione derivative-catalyzed caspase-3 inactivation could also be observed when DTT is substituted with dihydrolipoic acid, which exists widely in cells and might play an important role in the in vivo inactivation process in which the inhibitors inactivate caspase-3 in cells and then prevent the cells from apoptosis. These results provide valuable information for further development of small molecular inhibitors against caspase-3 or other oxidation-sensitive proteins. [ABSTRACT FROM AUTHOR]

AMP-activated protein kinase (AMPK) serves as an energy sensor and is considered a promising drug target for treatment of type II diabetes and obesity. A previous report has shown that mammalian AMPK al catalytic subunit including autoinhibitory domain was inactive. To test the hypothesis that small molecules can activate AMPK through antagonizing the autoinhibition in a subunits, we screened a chemical library with inactive human a1394 (αl, residues 1-394) and found a novel small-molecule activator, PT1, which dose-dependently activated AMPK α1394, α1335, α2398, and even heterotrimer α1β1γ1. Based on PT1-docked AMPK α1 subunit structure model and different mutations, we found PT1 might interact with Glu-96 and Lys156 residues near the autoinhibitory domain and directly relieve autoinhibition. Further studies using L6 myotubes showed that the phosphorylation of AMPK and its downstream substrate, acetyl-CoA carboxylase, were dose-dependently and time-dependently increased by PT1 without an increase in cellular AMP:ATP ratio. Moreover, in HeLa cells deficient in LKB1, PT1 enhanced AMPK phosphorylation, which can be inhibited by the calcium/calmodulin-dependent protein kinase kinases inhibitor STO-609 and AMPK inhibitor compound C. PT1 also lowered hepatic lipid content in a dose-dependent manner through AMPK activation in HepG2 cells, and this effect was diminished by compound C. Taken together, these data indicate that this small-molecule activator may directly activate AMPK via antagonizing the autoinhibition in vitro and in cells. This compound highlights the effort to discover novel AMPK activators and can be a useful tool for elucidating the mechanism responsible for conformational change and autoinhibitory regulation of AMPK. [ABSTRACT FROM AUTHOR]

AMP-activated protein kinase (AMPK) acts as an energy sensor, being activated by metabolic stresses and regulating cellular metabolism. AMPK is a heterotrimer consisting of a catalytic a subunit and two regulatory subunits, β and γ. It had been reported that the mammalian AMPK a subunit contained an autoinhibitory domain (α1: residues 313-392) and had little kinase activity. We have found that a conserved short segment of the a subunit (α1-(313-335)), which includes a predicted α-helix, is responsible for a subunit autoinhibition. The role of the residues in this segment for autoinhibition was further investigated by systematic site-directed mutation. Several hydrophobic and charged residues, in particular Leu-328, were found to be critical for α1 autoinhibition. An autoinhibitory structural model of human AMPK α1-(1-335) was constructed and revealed that Val-298 interacts with Leu-328 through hydrophobic bonding at a distance of about 4 Å and may stabilize the autoinhibitory conformation. Further mutation analysis showed that V298G mutation significantly activated the kinase activity. Moreover, the phosphorylation level of acetyl-CoA carboxylase, the AMPK downstream substrate, was significantly increased in COS7 cells overexpressing AMPK α1-(1-394) with deletion of residues 313-335 (Δα394) and a V298G or L328Q mutation, and the glucose uptake was also significantly enhanced in HepG2 cells transiently transfected with Δα394, V298G, or L328Q mutants, which indicated that these AMPK al mutants are constitutively active in mammalian cells and that interaction between Leu-328 and Val-298 plays an important role in AMPK a autoinhibitory function. [ABSTRACT FROM AUTHOR]