Contribution of the toxic advanced glycation end-productsreceptor axis in nonalcoholic steatohepatitis-related hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus(HCV), and non-hepatitis B/non-hepatitis C HCC(NBNCHCC) has also been identified as an etiological factor. Although the incidence of HCV-related HCC in Japan has decreased slightly in recent years, that of NBNC-HCC has increased. The onset mechanism of NBNC-HCC, which has various etiologies, remains unclear; however, nonalcoholic steatohepatitis(NASH), a severe form of nonalcoholic fatty liver disease, is known to be an important risk factor for NBNC-HCC. Among the different advanced glycation end-products(AGEs) formed by the Maillard reaction, glyceraldehyde-derived AGEs, the predominant components of toxic AGEs(TAGE), have been associated with NASH and NBNC-HCC, including NASH-related HCC. Furthermore, the expression of the receptor for AGEs(RAGE) has been correlated with the malignant progression of HCC. Therefore, TAGE induce oxidative stress by binding with RAGE may, in turn, lead to adverse effects, such as fibrosis and malignant transformation, in hepatic stellate cells and tumor cells during NASH or NASH-related HCC progression. The aim of this review was to examine the contribution of the TAGE-RAGE axis in NASH-related HCC.

Generation of glyceraldehyde-derived advanced glycation end-products in pancreatic cancer cells and the potential of tumor promotion

AIM To determine the possibility that diabetes mellitus promotes pancreatic ductal adenocarcinoma via glyceraldehyde(GA)-derived advanced glycation-end products(GA-AGEs).METHODS PANC-1,a human pancreatic cancer cell line,was treated with 1-4 mmol/L GA for 24 h. The cell viability and intracellular GA-AGEs were measured by WST-8 assay and slot blotting. Moreover,immunostaining of PANC-1 cells with an anti-GA-AGE antibody was performed. Western blotting(WB) was used to analyze the molecular weight of GA-AGEs. Heat shock proteins 90α,90β,70,27 and cleaved caspase-3 were analyzed by WB. In addition,PANC-1 cells were treated with GA-AGEs-bovine serum albumin(GA-AGEs-BSA),as a model of extracellular GA-AGEs,and proliferation of PANC-1 cells was measured.RESULTS In PANC-1 cells,GA induced the production of GA-AGEs and cell death in a dose-dependent manner. PANC-1 cell viability was approximately 40% with a 2 mmol/L GA treatment and decreased to almost 0% with a 4 mmol/L GA treatment(each significant difference was P < 0.01). Cells treated with 2 and 4 mmol/L GA produced 6.4 and 21.2 μg/mg protein of GA-AGEs,respectively(P <0.05 and P < 0.01). The dose-dependent production of some high-molecular-weight(HMW) complexes of HSP90β,HSP70,and HSP27 was observed following administration of GA. We considered HMW complexes to be dimers and trimers with GA-AGEs-mediated aggregation. Cleaved caspase-3 could not be detected with WB. Furthermore,10 and 20 μg/m L GA-AGEs-BSA was 27% and 34% greater than that of control cells,respectively(P < 0.05 and P < 0.01).CONCLUSION Although intracellular GA-AGEs induce pancreatic cancer cell death,their secretion and release may promote the proliferation of other pancreatic cancer cells.

Imaging assessment of photosensitizer emission induced by radionuclide-derived Cherenkov radiation using charge-coupled device optical imaging and long-pass filters

BACKGROUND Radionuclides produce Cherenkov radiation(CR),which can potentially activate photosensitizers(PSs)in phototherapy.Several groups have studied Cherenkov energy transfer to PSs using optical imaging;however,cost-effectively identifying whether PSs are excited by radionuclide-derived CR and detecting fluorescence emission from excited PSs remain a challenge.Many laboratories face the need for expensive dedicated equipment.AIM To cost-effectively confirm whether PSs are excited by radionuclide-derived CR and distinguish fluorescence emission from excited PSs.METHODS The absorbance and fluorescence spectra of PSs were measured using a microplate reader and fluorescence spectrometer to examine the photo-physical properties of PSs.To mitigate the need for expensive dedicated equipment and achieve the aim of the study,we developed a method that utilizes a chargecoupled device optical imaging system and appropriate long-pass filters of different wavelengths(manual sequential application of long-pass filters of 515,580,645,700,750,and 800 nm).Tetrakis(4-carboxyphenyl)porphyrin(TCPP)was utilized as a model PS.Different doses of copper-64(^(64)CuCl_(2))(4,2,and 1 mCi)were used as CR-producing radionuclides.Imaging and data acquisition were performed 0.5 h after sample preparation.Differential image analysis was conducted by using ImageJ software(National Institutes of Health)to visually evaluate TCPP fluorescence.RESULTS The maximum absorbance of TCPP was at 390-430 nm,and the emission peak was at 670 nm.The CR and CRinduced TCPP emissions were observed using the optical imaging system and the high-transmittance long-pass filters described above.The emission spectra of TCPP with a peak in the 645-700 nm window were obtained by calculation and subtraction based on the serial signal intensity(total flux)difference between^(64)CuCl_(2)+TCPP and^(64)CuCl_(2).Moreover,the differential fluorescence images of TCPP were obtained by subtracting the^(64)CuCl_(2)image from the^(64)CuCl_(2)+TCPP image.The experimental results considering different^(64)CuCl_(2)doses showed a dosedependent trend.These results demonstrate that a bioluminescence imaging device coupled with different longpass filters and subtraction image processing can confirm the emission spectra and differential fluorescence images of CR-induced TCPP.CONCLUSION This simple method identifies the PS fluorescence emission generated by radionuclide-derived CR and can contribute to accelerating the development of Cherenkov energy transfer imaging and the discovery of new PSs.

Glycer-AGEs-RAGE signaling enhances the angiogenic potential of hepatocellular carcinoma by upregulating VEGF expression

AIM:To investigate the effect of glyceraldehyde-derived advanced glycation end-products(Glycer-AGEs) on hepatocellular carcinoma(HCC)cells.METHODS:Two HCC cell lines(Hep3B and HepG2 cells)and human umbilical vein endothelial cells(HUVEC)were used.Cell viability was determined using the WST-8 assay.Western blotting,enzyme linked immunosorbent assay,and real-time reverse transcriptionpolymerase chain reactions were used to detect protein and mRNA.Angiogenesis was evaluated by assessing the proliferation,migration,and tube formation of HUVEC.RESULTS:The receptor for AGEs(RAGE)protein was detected in Hep3B and HepG2 cells.HepG2 cells werenot affected by the addition of Glycer-AGEs.GlycerAGEs markedly increased vascular endothelial growth factor(VEGF)mRNA and protein expression,which is one of the most potent angiogenic factors.Compared with the control unglycated bovine serum albumin(BSA) treatment,VEGF mRNA expression levels induced by the Glycer-AGEs treatment were 1.00±0.10 vs 1.92 ±0.09(P<0.01).Similarly,protein expression levels induced by the Glycer-AGEs treatment were 1.63±0.04 ng/mL vs 2.28±0.17 ng/mL for the 24 h treatment and 3.36±0.10 ng/mL vs 4.79±0.31 ng/mL for the 48 h treatment,respectively(P<0.01).Furthermore,compared with the effect of the control unglycated BSA-treated conditioned medium,the Glycer-AGEstreated conditioned medium significantly increased the proliferation,migration,and tube formation of HUVEC,with values of 122.4%±9.0%vs 144.5%±11.3%for cell viability,4.29±1.53 vs 6.78±1.84 for migration indices,and 71.0±7.5 vs 112.4±8.0 for the number of branching points,respectively(P<0.01).CONCLUSION:These results suggest that Glycer-AGEs-RAGE signaling enhances the angiogenic potential of HCC cells by upregulating VEGF expression.

Utility of linked color imaging for endoscopic diagnosis of early gastric cancer

BACKGROUND Linked color imaging(LCI) is a method of endoscopic imaging that emphasizes slight differences in red mucosal color.AIM To evaluate LCI in diagnostic endoscopy of early gastric cancer and to compare LCI and pathological findings.METHODS Endoscopic images were obtained for 39 patients(43 lesions) with early gastric cancer. Three endoscopists evaluated lesion recognition with white light imaging(WLI) and LCI. Color values in Commission Internationale de l'Eclairage(CIE)1976 L*a*b* color space were used to calculate the color difference(ΔE) between cancer lesions and non-cancer areas. After endoscopic submucosal dissection,blood vessel density in the surface layer of the gastric epithelium was evaluated pathologically. The identical region of interest was selected for analyses of endoscopic images(WLI and LCI) and pathological analyses.RESULTS LCI was superior for lesion recognition(P < 0.0001), and ΔE between cancer and non-cancer areas was significantly greater with LCI than WLI(29.4 vs 18.6, P <0.0001). Blood vessel density was significantly higher in cancer lesions(5.96% vs4.15%, P = 0.0004). An a* cut-off of ≥ 24 in CIE 1976 L*a*b* color space identified a cancer lesion using LCI with sensitivity of 76.7%, specificity of 93.0%, and accuracy of 84.9%.CONCLUSION LCI is more effective for recognition of early gastric cancer compared to WLI as a result of improved visualization of changes in redness. Surface blood vessel density was significantly higher in cancer lesions, and this result is consistent with LCI image analysis.

Involvement of the TAGE-RAGE system in non-alcoholic steatohepatitis: Novel treatment strategies

Non-alcoholic fatty liver disease(NAFLD)is a major cause of liver disease around the world.It includes a spectrum of conditions from simple steatosis to non-alcoholic steatohepatitis(NASH)and can lead to fibrosis,cirrhosis,liver failure,and/or hepatocellular carcinoma.NAFLD is also associated with other medical conditions such as obesity,diabetes mellitus(DM),metabolic syn-drome,hypertension,insulin resistance,hyperlipidemia,and cardiovascular disease(CVD).In diabetes,chronic hyperglycemia contributes to the development of both macro-and microvascular conditions through a variety of metabolic pathways.Thus,it can cause a variety of metabolic and hemodynamic conditions,including upregulated advanced glycation end-products(AGEs)synthesis.In our previous study,the most abundant type of toxic AGEs(TAGE);i.e.,glyceraldehyde-derived AGEs,were found to make a significant contribution to the pathogenesis of DM-induced angiopathy.Furthermore,accumulating evidence suggests that the binding of TAGE with their receptor(RAGE)induces oxidative damage,promotes inflammation,and causes changes in intracellular signaling and the expression levels of certain genes in various cell populations including hepatocytes and hepatic stellate cells.All of these effects could facilitate the pathogenesis of hypertension,cancer,diabetic vascular complications,CVD,dementia,and NASH.Thus,inhibiting TAGE synthesis,preventing TAGE from binding to RAGE,and downregulating RAGE expression and/or the expression of associated effector molecules all have potential as therapeutic strategies against NASH.Here,we examine the contributions of RAGE and TAGE to various conditions and novel treatments that target them in order to prevent the development and/or progression of NASH.

In vitro identification of nonalcoholic fatty liver diseaserelated protein hnRNPM

AIM:To study the formation of intracellular glyceraldehyde-derived advanced glycation end products(Glycer-AGEs)in the presence of high concentrations of fructose.METHODS:Cells of the human hepatocyte cell line Hep3B were incubated with or without fructose for five days,and the corresponding cell lysates were separated by two-dimensional gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis.Glycer-AGEs were detected with the anti-Glycer-AGEs antibody.Furthermore,the identification of the proteins that are modified by glyceraldehyde in the presence of high concentrations of fructose was conducted using matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).The protein and m RNA levels were determined by Western blotting and realtime reverse transcription PCR,respectively.RESULTS:The results of the two-dimensional gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a greater amount of GlycerAGEs in the sample exposed to high concentrations of fructose than in the control.The detected GlycerAGEs showed isoelectric points in the range of 8.0-9.0and molecular weights in the range of 60-80 k Da.The heterogeneous nuclear ribonucleoprotein M(hn RNPM),which plays an important role in regulating gene expression by processing heterogeneous nuclear RNAs to form mature m RNAs,was identified as a modified protein using MALDI-TOF-MS.Increasing the concentration of fructose in the medium induced a concentration-dependent increase in the generated Glycer-AGEs.Furthermore,in an experiment using glyceraldehyde,which is a precursor of Glycer-AGEs,hn RNPM was found to be more easily glycated than the other proteins.CONCLUSION:The results suggest that glyceraldehyde-modified hn RNPM alters gene expression.This change may cause adverse effects in hepatocytes and may serve as a target for therapeutic intervention.

Laparoscopic Kasai portoenterostomy can be a standard surgical procedure for treatment of biliary atresia

BACKGROUND Biliary atresia(BA)is a rare pediatric disease.AIM To compare the outcomes of laparoscopic portoenterostomy(Lap-PE)with those of laparotomy(Open-PE)at a single institution.METHODS The surgical outcomes of PE were retrospectively analyzed for patients with a non-correctable type of BA from 2003 to 2020.RESULTS Throughout the assessment period,119 patients received PE for BA treatment,including 66 Open-PE and 53 Lap-PE cases.Although the operation duration was longer(medians:for Open-PE,242 min;for Lap-PE,341 min;P<0.001),blood loss was considerably less(medians:for Open-PE,52 mL;for Lap-PE,24 mL;P<0.001)in the Lap-PE group than in the Open-PE group.The postoperative recovery of the Lap-PE group was more favorable;specifically,both times to resume oral intake and drain removal were significantly shorter in the Lap-PE group.Complete resolution of jaundice was observed in 45 Open-PE cases and 42 Lap-PE cases,with no statistically significant difference(P=0.176).Native liver survival rates were>80%for both groups for the first half year post surgery,followed by a gradual decrease with time;there were no statistically significant differences in the native liver survival rates for any durations assessed.CONCLUSION Lap-PE could be a standard therapy for BA.

Gene Expression Changes Associated with the Loss of Heterogeneous Nuclear Ribonucleoprotein M Function

Advanced glycation endproducts (AGEs) are formed by the nonenzymatic reaction of sugars with proteins. Glycation may adversely affect proteins, such as by inducing a loss of function. It has been shown that glyceraldehyde-derived AGEs (Glycer-AGEs) accumulate in the liver of patients with nonalcoholic steatohepatitis (NASH). Previously, we showed the formation of intracellular Glycer-AGEs upon exposure of hepatocytes to fructose in vitro, and identified an RNA-binding protein, heterogeneous nuclear ribonucleoprotein M (HNRNPM), as a target for glycation. However, the impact of glycated HNRNPM in NASH remains poorly understood. In this study, we examined gene expression changes caused by HNRNPM knockdown, and investigated the up- and down-regulated genes as noninvasive biomarker candidates for NASH. Microarray analysis after HNRNPM knockdown showed that the levels of 138 transcripts were increased, while those of 100 transcripts were decreased as compared with those in the control. Gene Ontology-based functional analysis showed that 14 upregulated and 9 downregulated genes were associated with the extracellular space, which may enable their detection using blood tests. Among these, six of the up- and down-regulated genes were associated with the extracellular exosome. These results suggest that the loss of HNRNPM function by glycation is reflected extracellularly. Therefore, the identified genes may serve as noninvasive biomarkers for Glycer-AGEs-related NASH.

Neurosteroids as stress modulators and neurotherapeutics: lessons from the retina

Neurosteroids are rapidly emerging as important new therapies in neuropsychiatry, with one such agent, brexanolone, already approved for treatment of postpartum depression, and others on the horizon. These steroids have unique properties, including neuroprotective effects that could benefit a wide range of brain illnesses including depression, anxiety, epilepsy, and neurodegeneration. Over the past 25 years, our group has developed ex vivo rodent models to examine factors contributing to several forms of neurodegeneration in the retina. In the course of this work, we have developed a model of acute closed angle glaucoma that involves incubation of ex vivo retinas under hyperbaric conditions and results in neuronal and axonal changes that mimic glaucoma. We have used this model to determine neuroprotective mechanisms that could have therapeutic implications. In particular, we have focused on the role of both endogenous and exogenous neurosteroids in modulating the effects of acute high pressure. Endogenous allopregnanolone, a major stress-activated neurosteroid in the brain and retina, helps to prevent severe pressure-induced retinal excitotoxicity but is unable to protect against degenerative changes in ganglion cells and their axons under hyperbaric conditions. However, exogenous allopregnanolone, at a pharmacological concentration, completely preserves retinal structure and does so by combined effects on gamma-aminobutyric acid type A receptors and stimulation of the cellular process of macroautophagy. Surprisingly, the enantiomer of allopregnanolone, which is inactive at gamma-aminobutyric acid type A receptors, is equally retinoprotective and acts primarily via autophagy. Both enantiomers are also equally effective in preserving retinal structure and function in an in vivo glaucoma model. These studies in the retina have important implications for the ongoing development of allopregnanolone and other neurosteroids as therapeutics for neuropsychiatric illnesses.

MEF2C regulates osteoclastogenesis and pathologic bone resorption via c-FOS

Osteoporosis is a metabolic bone disease with dysregulated coupling between bone resorption and bone formation,which results in decreased bone mineral density.The MEF2C locus,which encodes the transcription factor MADS box transcription enhancer factor 2,polypeptide C(MEF2C),is strongly associated with adult osteoporosis and osteoporotic fractures.Although the role of MEF2C in bone and cartilage formation by osteoblasts,osteocytes,and chondrocytes has been studied,the role of MEF2C in osteoclasts,which mediate bone resorption,remains unclear.In this study,we identified MEF2C as a positive regulator of human and mouse osteoclast differentiation.While decreased MEF2C expression resulted in diminished osteoclastogenesis,ectopic expression of MEF2C enhanced osteoclast generation.Using transcriptomic and bioinformatic approaches,we found that MEF2C promotes the RANKL-mediated induction of the transcription factors c-FOS and NFATc1,which play a key role in osteoclastogenesis.Mechanistically,MEF2C binds to FOS regulatory regions to induce c-FOS expression,leading to the activation of NFATC1 and downstream osteoclastogenesis.Inducible deletion of Mef2c in mice resulted in increased bone mass under physiological conditions and protected mice from bone erosion by diminishing osteoclast formation in K/BxN serum induced arthritis,a murine model of inflammatory arthritis.Our findings reveal direct regulation of osteoclasts by MEF2C,thus adding osteoclasts as a cell type in which altered MEF2C expression or function can contribute to pathological bone remodeling.

Novel zinc alloys for biodegradable surgical staples

BACKGROUND The development of biodegradable surgical staples is desirable as non-biodegradable Ti alloy staples reside in the human body long after wound healing, which can cause allergic/foreign-body reactions, adhesion, or other adverse effects. In order to develop a biodegradable alloy suitable for the fabrication of surgical staples, we hypothesized that Zn, a known biodegradable metal, could be alloyed with various elements to improve the mechanical properties while retaining biodegradability and biocompatibility. Considering their biocompatibility, Mg, Ca, Mn, and Cu were selected as candidate alloying elements, alongside Ti, the main material of clinically available surgical staples.AIM To investigate the in vitro mechanical properties and degradation behavior and in vivo safety and feasibility of biodegradable Zn alloy staples.METHODS Tensile and bending tests were conducted to evaluate the mechanical properties of binary Zn alloys with 0.1–6 wt.% Mg, Ca, Mn, Cu, or Ti. Based on the results,three promising Zn alloy compositions were devised for staple applications(wt.%): Zn-1.0Cu-0.2Mn-0.1Ti(Zn alloy 1), Zn-1.0Mn-0.1Ti(Zn alloy 2), and Zn-1.0Cu-0.1Ti(Zn alloy 3). Immersion tests were performed at 37℃ for 4 wk using fed-state simulated intestinal fluid(Fe SSIF) and Hank’s balanced salt solution(HBSS). The corrosion rate was estimated from the weight loss of staples during immersion. Nine rabbits were subjected to gastric resection using each Zn alloy staple, and a clinically available Ti staple was used for another group of nine rabbits. Three in each group were sacrificed at 1, 4, and 12 wk post-operation.RESULTS Additions of ≤1 wt.% Mn or Cu and 0.1 wt.% Ti improved the yield strength without excessive deterioration of elongation or bendability. Immersion tests revealed no gas evolution or staple fracture in any of the Zn alloy staples. The corrosion rates of Zn alloy staples 1, 2, and 3 were 0.02 mm/year in HBSS and 0.12, 0.11, and 0.13 mm/year, respectively, in Fe SSIF. These degradation times are sufficient for wound healing. The degradation rate is notably increased under low pH conditions. Scanning electron microscopy and energy dispersive spectrometry surface analyses of the staples after immersion indicated that the component elements eluted as ions in Fe SSIF, whereas corrosion products were produced in HBSS, inhibiting Zn dissolution. In the animal study, none of the Zn alloy staples caused technical failure, and all rabbits survived without complications. Histopathological analysis revealed no severe inflammatory reaction around the Zn alloy staples.CONCLUSION Staples made of Zn-1.0Cu-0.2Mn-0.1Ti, Zn-1.0Mn-0.1Ti, and Zn-1.0Cu-0.1Ti exhibit acceptable in vitro mechanical properties, proper degradation behavior,and in vivo safety and feasibility. They are promising candidates for biodegradable staples.

Whole-body PET tracking of a D-dodecapeptide and its radiotheranostic potential for PD-L1 overexpressing tumors

Peptides that are composed of dextrorotary(D)-amino acids have gained increasing attention as a potential therapeutic class.However,our understanding of the in vivo fate of D-peptides is limited.This highlights the need for whole-body,quantitative tracking of D-peptides to better understand how they interact with the living body.Here,we used mouse models to track the movement of a programmed death-ligand 1(PD-L1)-targeting D-dodecapeptide antagonist(DPA)using positron emission tomography(PET).More specifically,we profiled the metabolic routes of[^(64)Cu]DPA and investigated the tumor engagement of[^(64)Cu/^(68)Ga]DPA in mouse models.Our results revealed that intact[^(64)Cu/^(68)Ga]DPA was primarily eliminated by the kidneys and had a notable accumulation in tumors.Moreover,a single dose of[^(64)Cu]DPA effectively delayed tumor growth and improved the survival of mice.Collectively,these results not only deepen our knowledge of the in vivo fate of D-peptides,but also underscore the utility of D-peptides as radiopharmaceuticals.

Inhibition of BET selectively eliminates undifferentiated pluripotent stem cells

Embryonic stem cells(ESCs) maintain their cellular identity through the systematic regulation of master transcription factors and chromatin remodeling complexes. Recent work has shown that the unusually large-scale enhancers—namely super-enhancers(SEs), on which BRD4, a member of the bromodomain and extraterminal domain(BET) family is highly enriched—could regulate pluripotency-related transcription factors. Moreover, inhibition of BRD4 binding on SEs has been shown to induce the differentiation of ESCs. However, the underlying mechanism of BRD4 inhibition-mediated stem cell differentiation remains elusive. Here we show that both mouse and human ESCs lose their capacity for self-renewal upon treatment with JQ1, a selective inhibitor of BET family including BRD4, with rapid suppression of pluripotency-associated genes. Notably, a high concentration of JQ1 could selectively eliminate ESCs via apoptosis, without affecting the functionality of differentiated somatic cells from ESCs, suggesting that inhibition of BET may have a beneficial effect on the development of pluripotent stem cell-based cell therapy.

Self-Assembly of Constrained Cyclic Peptides Controlled by Ring Size

The de novo design of new peptide assemblies that expands the repertoire of biomaterial nanostructures has been of a tremendous challenge.Hence,it is evident that a successful research achievement in this area would increase the understanding of molecular interactions in supramolecules and create novel scaffolds exploitable in biotechnology and synthetic biology.The manipulation of cyclic peptide self-assembly is particularly intriguing for this purpose.Herein,we report that a novel type of cyclic peptides,referred to as chiral tether constrained cyclic peptides(CCP),shows promising self-assembly properties.CCPs are the first example of a controllable assembly of all-L-α-cyclic peptides with different ring sizes.A noteworthy feature of the CCP system is good tolerance of different secondary structures,ring size,and peptide sequence.Based on this system,a variety of nanostructures could be constructed,which display different physical properties,rendering it an excellent platform for molecular interaction studies.Further,demonstrate potential applications of these peptide assemblies in bioimaging and energy storage.

Development of a highly-specific ^(18)F-labeled irreversible positron emission tomography tracer for monoacylglycerol lipase mapping

As a serine hydrolase,monoacylglycerol lipase(MAGL) is principally responsible for the metabolism of 2-arachidonoylglycerol(2-AG) in the central nervous system(CNS),leading to the formation of arachidonic acid(AA).Dysfunction of MAGL has been associated with multiple CNS disorders and symptoms,including neuroinflammation,cognitive impairment,epileptogenesis,nociception and neurodegenerative diseases.Inhibition of MAGL provides a promising therapeutic direction for the treatment of these conditions,and a MAGL positron emission tomography(PET) probe would greatly facilitate preclinical and clinical development of MAGL inhibitors.Herein,we design and synthesize a small library of fluoropyridyl-containing MAGL inhibitor candidates.Pharmacological evaluation of these candidates by activity-based protein profiling identified 14 as a lead compound,which was then radiolabeled with fluorine-18 via a facile SNAr reaction to form 2-[^(18)F]fluoropyridine scaffold.Good blood-brain barrier permeability and high in vivo specific binding was demonstrated for radioligand [^(18)F]14(also named as [^(18)F]MAGL-1902).This work may serve as a roadmap for clinical translation and further design of potent 18F-labeled MAGL PET tracers.

PET imaging on neurofunctional changes after optogenetic stimulation in a rat model of panic disorder

Panic disorder (PD) is an acute paroxysmal anxiety disorder with poorly understood pathophysiology. The dorsal periaqueductal gray (dPAG) is involved in the genesis of PD. However, the downstream neurofunctional changes of the dPAG during panic attacks have yet to be evaluated in vivo. In this study, optogenetic stimulation to the dPAG was performed to induce panic-like behaviors, and in vivo positron emission tomography (PET) imaging with ,8F-flurodeoxyglucose (18F-FDG) was conducted to evaluate neurofunctional changes before and after the optogenetic stimulation. Compared with the baseline, post-optogenetic stimulation PET imaging demonstrated that the glucose metabolism significantly increased (P < 0.001) in dPAG, the cuneiform nucleus, the cerebellar lobule, the cingulate cortex, the alveus of the hippocampus, the primary visual cortex, the septohypothalamic nucleus, and the retrosplenial granular cortex but significantly decreased (P < 0.001) in the basal ganglia, the frontal cortex, the forceps minor corpus callosum, the primary somatosensory cortex, the primary motor cortex, the secondary visual cortex, and the dorsal lateral geniculate nucleus. Taken together, these data indicated that in vivo PET imaging can successfully detect downstream neurofunctional changes involved in the panic attacks after optogenetic stimulation to the dPAG.

Peptide-based nanomaterials:Self-assembly,properties and applications

Peptide-based materials that have diverse structures and functionalities are an important type of biomaterials.In former times,peptide-based nanomaterials with excellent stability were constructed through self-assembly.Compared with individual peptides,peptide-based self-assembly nanomaterials that form well-ordered superstructures possess many advantages such as good thermo-and mechanical stability,semiconductivity,piezoelectricity and optical properties.Moreover,due to their excellent biocompatibility and biological activity,peptide-based self-assembly nanomaterials have been vastly used in different fields.In this review,we provide the advances of peptide-based self-assembly nanostructures,focusing on the driving forces that dominate peptide self-assembly and assembly mechanisms of peptides.After that,we outline the synthesis and properties of peptide-based nanomaterials,followed by the applications of functional peptide nanomaterials.Finally,we provide perspectives on the challenges and future of peptide-based nanomaterials.

The increase in surface CXCR4 expression on lung extravascular neutrophils and its effects on neutrophils during endotoxin-induced lung injury

Inflammatory stimuli,such as a microbes or lipopolysaccharides,induce a rapid release of neutrophils from the bone marrow and promote neutrophil migration into inflamed sites to promote host defense.However,an excess accumulation and retention of neutrophils in inflamed tissue can cause severe tissue injuries in the later stages of inflammation.Recent studies have reported that both CXCL12 levels in injured lungs and its receptor,CXCR4,on accumulated neutrophils in injured lungs,increased;furthermore,these studies showed that the CXCL12/CXCR4 signaling pathway participated in neutrophil accumulation in the later stages of lipopolysaccharide(LPS)-induced lung injury.However,the mechanisms underlying this increase in surface CXCR4 expression in neutrophils remain unclear.In this study,we found that surface CXCR4 expression increased in extravascular,but not intravascular,neutrophils in the lungs of LPS-induced lung injury model mice.Furthermore,ex vivo studies revealed that CXCL12 acted not only as a chemoattractant,but also as a suppressor of cell death for the lung neutrophils expressing CXCR4.Sulfatide,one of the native ligands for L-selectin,induced the increase of surface CXCR4 expression on isolated circulating neutrophils,suggesting that the activation of L-selectin may be involved in the increase in surface CXCR4.Our findings show that surface CXCR4 levels on neutrophils increase after extravasation into injured lungs,possibly through the activation of L-selectin.The CXCL12/CXCR4 signaling pathway plays an important role in the modulation of neutrophil activity during acute lung injury,not only by promoting chemotaxis but also by suppressing cell death.

Skin conductance reflects perioperative stress in dogs

Perioperative stress arises when patients are undergoing anesthesia and surgical intervention[1].The optimum care will not be given without sufficient monitoring the stress.Stress-related hormones,such as cortisol,adrenaline and noradorenaline,are measured as a traditional indicator of perioperative stress in animals,but it needs blood or salivary which are difficult to be sampled in some cases[2].Some noninvasive and easier measuring indicators of perioperative stress have been looked for in order to give more appropriate care for animals.