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Target identification of bioactive compounds is important for understanding their mechanisms of action and provides critical insights into their therapeutic utility. While it remains a challenge, unbiased chemoproteomics strategy using clickable photoaffinity probes is a useful and validated approach for target identification. One major limitation of this approach is the efficient synthesis of appropriately substituted clickable photoaffinity probes. Herein, we describe an efficient and consistent method to prepare such probes. We further employed this method to prepare a highly stereo-congested probe based on naturally occurring triterpenoid betulinic acid. With this photoaffinity probe, we identified tropomyosin as a novel target for betulinic acid that can account for the unique biological phenotype on cellular cytoskeleton induced by betulinic acid.
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Objective:To investigate the inhibitory effect and underlying mechanism of gamma-secretase inhibitor blocking Notch1 signaling on retinal neovascularization caused by oxygen-induced retinopathy (OIR) in mice.Methods:To establish the OIR model, 7-day-old pups of C57BL/6J mice were exposed to 75% oxygen together with their mother until postnatal day (P)12.On P12, the mice were transferred to room air.All the mice were randomly divided into three groups, OIR group as control group, OIR+ DAPT group and OIR+ DMSO group receiving 1 μl intravitreal injection of gamma-secretase inhibitor (DAPT, 10 mmol/L) and 1∶20 DMSO dilution respectively.The right eye was taken as experimental eye.The mice were euthanized on P17 and the eyes were harvested to obtain retinas for further investigation.The total proteins were extracted from the retinas.The relative expression levels of Notch1 signal pathway and its downstream Hes1, the markers of M1 phenotype inducible nitric oxide synthase (iNOS) and M2 phenotype arginase-1 (Arg-1) microglia were measured by western blot.Retinal flat mounts were made and the retinal vessels were stained with isolectin B4 (IB4) to investigate the relative retinal neovascularization areas which was calculated as the ratio of neovascularization area/retinal area.The mumber of the neovascular endothelium cells beyond the inner limiting membrane was observed by hematoxylin-eosin staining.The use and care of animals complied with ARVO statement.This study protocol was approved by the Animal Ethics Committee of Guangdong Provincial People's Hospital (No.KY-Z-2021-2015-01).Results:The relative protein expression levels of Notch1 and Hes1 in OIR+ DAPT group, OIR group, and OIR+ DMSO group were 0.68±0.06 and 0.70±0.08, 1.00±0.00 and 1.00±0.00, 1.03±0.08 and 1.02±0.07, respectively, with statistically significant differences among them ( F=70.62, 53.65; both at P<0.01). Compared with the OIR group and OIR+ DMSO group, the expressions of Notch1 and Hes1 were significantly reduced in OIR+ DAPT group (all at P<0.01). The relative protein expression levels of iNOS and Arg-1 in OIR+ DAPT group, OIR group, and OIR+ DMSO group were 0.74±0.07 and 1.49±0.12, 1.00±0.00 and 1.00±0.00, 1.04±0.10 and 0.94±0.07, respectively, showing statistically significant differences ( F=31.63, 89.32; both at P<0.01). Compared with OIR group and OIR+ DMSO group, the expression of iNOS in OIR+ DAPT group was significantly reduced, and the expression of Arg-1 was significantly increased (all at P<0.01). The relative neovascularization area and the number of neovascular endothelium cells beyond the inner limiting membrane in OIR+ DAPT group, OIR group, and OIR+ DMSO group were (8.82±2.71)% and 38.17±3.29, (22.32±5.34)% and 60.83±5.11, (20.27±3.36)% and 58.67±4.75, respectively, showing statistically significant differences ( F=33.72, 39.44; both at P<0.01). The relative neovascularization area and the number of neovascular endothelium cells in OIR+ DAPT group were significantly reduced in comparison with OIR group and OIR+ DMSO group (all at P<0.01). Conclusions:Intravitreal injection of DAPT can inhibit the retinal neovascularization in OIR mice through blocking Notch1 signaling activation and promoting retinal microglia polarization from M1 to M2 phenotype.
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The intervention therapy targeting vascular endothelial growth factor (VEGF) has become a specific and effective method for the treatment of diabetic retinopathy (DR). However, some patients did not respond or responded poorly to anti-VEGF therapy, and its effects of eliminating edema and improving vision appear to be unstable in the same patient. Hypoxia-inducible factor-1α (HIF-1α), an important upstream transcriptional regulator of VEGF, is an oxygen concentration-sensitive protein expressed in tissues under hypoxia. It can simultaneously target many downstream target genes except VEGF, such as placental growth factor and angiopoietin-like protein 4, to cause blood-retinal barrier damage and neovascularization, and thus participate in various pathological changes of DR to promote the occurrence and development of DR. Therefore, direct intervention of HIF-1α or targeting one or more downstream target genes regulated by HIF-1α to treat DR may have better efficacy. In the future, the development of effective and safe HIF inhibitors or anti-VEGF with HIF-1α other target gene inhibitors may have broader clinical application prospects.
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Diabetic retinopathy (DR) is one of the most common causes of visual impairment and blindness in diabetic patients.It is particularly important to set up simpler,safer,non-invasive and highly effective methods for diagnosis as well as monitoring DR.A variety of new fundus imaging techniques show great advantages in early diagnosis,treatment and monitoring of DR in recent years,The main characteristics of wide-field scanning laser imaging system is achieving a large range of retinal image in a single photograph and without mydriasis.It provides several options for color images,FFA and FAF,which satisfy to detect the retina,choroid and vascular structure.Multi spectral fundus imaging system is suitable for DR screening,because it is able to recognize the typical characteristics of DR,such as microaneurysms,hemorrhage and exudation,and is non-invasive and convenient.OCT angiography is a quantitative examination that provides foveal avascular zone area,macular blood flow density,which provides strong evidence for DR diagnosis.The improvement of these new techniques will help us to build up a personalized evaluation system of DR.
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Objective To research the genetic susceptibility of proliferative diabetic retinopathy (PDR) in Han patients with type 2 diabetes from Southern China.Methods A cross-sectional study was performed under the informed consent of the patients.Patients with type 2 diabetes in the Dongguan Eye Study from September 2011 to February 2012 and relative patients treated in Guangdong General Hospital from July 2017 to March 2018 were included in this study,including 100 patients with diabetes mellitus(DM) and 120 patients with PDR.Whole exome sequencing was used to identify DNA mutation in peripheral blood samples from 22 type 2 diabetic patients without retinopathy (DM group) and 23 diabetic patients with PDR (PDR group).Genotype and allele of the nine selected single-nucleotide polymorphisms (SNPs) were tested and analyzed by SnaPshot technology in another 78 DM patients without retinopathy and 97 PDR patients.Results A total of 75 SNPs were associated with PDR (P＜0.01),involving 53 genes.Eleven gene loci were in the exon region and 7 were non-synonymous mutations.Nine exon loci of 8 genes with significant differences were screened out for the verification.SnaPshot SNP genotyping technique found that there were no significant differences in allele and genotype frequency in the nine selected SNPs between PDR group and DM group (all at P＞0.05).However,7 haplotypes distribution frequencies were significantly different between PDR group and DM group (all at P＜0.01).Hapl and Hap4 might reduce the risk of PDR (both at OR＜1,P＜0.05),and Hap2 might increase the risk of PDR (OR＞ 1,P＜0.05).Conclusions The occurrence of PDR probably has a genetic susceptibility in type 2 DM patients of Han nationality in Southern China.
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Background Diabetic retinopathy (DR) has become the main cause of blindness in the world,But the etiology of DR is still not clear,and the results of the studies on the risk factors of DR are not completely consistent.Fully understanding the risk factors of DR has an important clinical value for the prevention and treatment of DR.Objective This study was to analyze the prevalence rate and risk factors of DR inpatients with type 2 diabetes and provide a basis for the establishment of ophthalmic intervention programs and measures for diabetic inpatients.Methods Cross sectional study was performed.Four hundred and seventy three patients with type 2 diabetes in the department of endocrinology,Dongguan People's Hospital from July 2011 to July 2012 were included.The patients were divided into DR group and non diabetic retinopathy (NDR) group.The DR group was subdivided into mild,moderate and severe non-proliferative DR (NPDR) group and proliferative DR (PDR) group.The sex and age of patients,course of diabetes,body mass index (BMI),systolic blood pressure,diastolic blood pressure,fasting blood glucose (FBG),2 hours postprandial blood glucose (2 h PBG),glycosylated hemoglobin (HbA1 c),fasting insulin,2 hours postprandial insulin,high density lipoprotein cholesterol,low density lipoprotein cholesterol,apolipoprotein A1 (APOA1),APOB,alpha lipoprotein,total cholesterol,three glycerol,urea nitrogen,creatinine,uric acid,percentage of neutrophil,24 hours urinary albumin total (ALBU-24 h) and ALBU were detected.Logistic regression was used to analyze the relationship between DR and various factors,and the risk factors of DR were screened out.Results The prevalence of DR inpatients with type 2 diabetes was 28.33％,the prevalence of mild,moderate and severe NPDR were 2.54％,16.28％ and 4.23％,respectively,the prevalence of PDR was 5.29％.The prevalence of DME was 10.36％ in the DR patients.The course of diabetes,the levels of serum lipoprotein,creatinine,ALBU-24 h and ALBU were statistically significant between DR group and NDR group (all at P＜0.05).By stepwise Logistic regression analysis,the course of disease,FBG were identified as the independent risk factors of DR (course of disease:odds ratio [OR] =1.155,95 ％ confidence interval [CI]:1.067-1.251;FBG:OR =1.313,95％ CI:1.071-1.610).Conclusions The course of diabetes,lipoprotein,creatinine,ALBU-24h,ALBU are closely related to the occurrence and development of DR.The course of diabetes and FBG are the independent risk factors of DR.
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Epigenetics is a branch of conventional genetics and is an emerging research field in biomedicine.Epigenetic factors regulate gene function and phenotype by the modulation of DNA methylation,histone modification,non-coding RNA such as microRNA expression instead of changing the DNA sequence.Therefore,it is thought to be a discipline associated with life science.Epigenetics is opening new means for understanding ocular development and ocular diseases related to aging and environment,and relevant study is increasingly emphasized because epigenetic inheritance is considered to be a reversible process.Like other ocular tissues,the growth,differentiation,senescence and epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) are modulated by epigenetic inheritance.Epigenetic inheritance participates in the regulation of gene phenotype,chromatin structure,non-coding RNAs,and cellular differentiation and potential influent in lens diseases such as cataracts.Therefore it may provide new insight of the pathogenesis of cataracts and development of novel treatment options by vigorously carrying lens research on epigenetics.Domestic ophthalmologists should keep watchful eye to these studies.
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Background The conventional study of antigen-presenting cells(APCs)in eye relies on in vitro histoimmunochemistry,but its outcome is influenced by many factors.The anterior chamber injection of fluoresceinmarked antibody was used as a new approach before,however,it is liable to lead to injury of cornea.The intravitreal injection of fluorescein-labeled antibody may be important for the in vivo study of the phenotype features of APCs in iris,which is significant for evaluating the function of APCs in immune homeostasis.Objective This study was to investigate the phenotype characters,distribution and morphology of different types of APCs in the normal murine iris.Methods Fifty-one SPF female BALB/c mice(from 6-to 8-week old)were randomized into 17 groups according to the injection of different antibodies.Alexa Fluor 594 or Alexa Fluor 488-tagged ovalbumin (OVA),CD11 c,major histocompatibility complex Ⅱ (MHC-Ⅱ),F4/80,B7-1 and B7-2 monoclonal antibodies or mixtures of two antibodies (2.0 μl)were intravitreally injected at 0.5 mm far from corneal limbus with microneedle under the biomicroscope.The iris tissues were isolated 24 hours after injection.The phenotype characters,precise distribution and morphology of different types of APCs were identified by epifluorescence microscope and laser confocal microscope.In vitro staining was also performed to validate the in vivo staining results.Results After in vivo staining via intravitreal injection,the cell positive for OVA as well as MHC-Ⅱ,F4/80,CD11 c,B7-1 and B7-2 were exhibited with the regular networkline appearance throughout the normal murine iris.Positive cells tagged with Alexa Fluor 594 or Alexa Fluor 488 presented the red or green fluorescence.Double-fluorescein staining showed that about 90％ of F4/80+ cells were OVA+,and MHC-Ⅱ was expressed in about 60％ of F4/80+ cells and CD11c+cells,and about 35％ of F4/80+ cells and CD1 1 c+ cells expressed B7-1 and B7-2 simultaneously,and over 70％ of OVA+ cells were positive to MHC-Ⅱ.These labeled cells were identified as two populations based on their shape.One type was dendritiform cell (DC) with a small cell body and many long dendrites,including OVA+,CD1 1 c+,F4/80+ cells and MHC-Ⅱ + cells ; and the other types were polymorphic population being round,pleomorphic or irregular shape with a large cell body and a few short dendrities,including B7-1 + and B7-2+ cells.Conclusions In vivo intravitreal injection of labeled antibodies can be adapted to visualize the labeled cells in the murine iris.APCs with distinct morphologies,phenotypes and distribution may contribute to the immunologically privileged feature and inflammation of the eye.
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Diabetic retinopathy (DR) is one of common causes of vision loss.Recent years,progress has been made on the signal pathway in DR which provides more theoretical basis for clinical therapies and more chance for developing targeted therapeutic drugs.Understanding the biological function of the signal pathway in DR is helpful for physicians to selectively control its biological activities,make medical decisions and optimize new approaches to the treatment of DR.How to closely combine the study of signal pathway and targeted therapy in practice is a key link of improving the therapeutic effect of DR.Therefore,we should pay attention to translational medicine and reinforce targeted therapy in DR.
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Studies show that heme oxygenase-1 (HO-1) can promote the tumor neovascularization via interacting with angiogenic factors,such as vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1.On the other hand,HO-1 may suppress angiogenesis in tumors via inhibiting the transcription of NF-кB.In a word,HO-1 may participate in the pathophysiological process of tumor angiogenesis,and may be a new target for cancer treatment.