URP20 improves corneal injury caused by alkali burns combined with pathogenic bacterial infection in rats.

Corneal alkali burns often occur in industrial production and daily life, combined with infection, and may cause severe eye disease. Oxidative stress and neovascularization (NV) are important factors leading to a poor prognosis. URP20 is an antimicrobial peptide that has been proven to treat bacterial keratitis in rats through antibacterial and anti-NV effects. Therefore, in this study, the protective effect and influence mechanism of URP20 were explored in a rat model of alkali burn together with pathogenic bacteria (Staphylococcus aureus and Escherichia coli) infection. In addition, human umbilical vein endothelial cells (HUVECs) and human corneal epithelial cells (HCECs) were selected to verify the effects of URP20 on vascularization and oxidative stress. The results showed that URP20 treatment could protect corneal tissue, reduce corneal turbidity, and reduce the NV pathological score. Furthermore, URP20 significantly inhibited the expression of the vascularization marker proteins VEGFR2 and CD31. URP20 also reduced the migration ability of HUVECs. In terms of oxidative stress, URP20 significantly upregulated SOD and GSH contents in corneal tissue and HCECs (treated with 200 µM H2O2) and promoted the expression of the antioxidant protein Nrf2/HO-1. At the same time, MDA and ROS levels were also inhibited. In conclusion, URP20 could improve corneal injury combined with bacterial infection in rats caused by alkali burns through antibacterial, anti-NV, and antioxidant activities.

Inhibition of STIM1 alleviates high glucose-induced proliferation and fibrosis by inducing autophagy in mesangial cells.

Diabetic nephropathy (DN) is a renal microvascular complication caused by diabetes mellitus. One of the most typical characteristics of DN is glomerular mesangial cells (GMCs) proliferation. Stromal interaction molecule 1 (STIM1), a Ca2+ channel, is involved in many diseases. In this study, we investigated the role of STIM1 in the proliferation and fibrosis in high glucose (HG)-induced HBZY-1 cells. We found that the expression of STIM1 was increased in renal tissues of diabetic rat and HBZY-1 cells stimulated by HG. Downregulation of STIM1-mediated SOCE suppressed hyperglycemic cell proliferation and fibrosis by activating autophagy. In addition, the inhibitory effect of downregulating STIM1 on cells was blocked by autophagy inhibitor Bafilomycin A1 (BafA1). Moreover, this experiment also showed that STIM1 regulated autophagy, cell proliferation and fibrosis via PI3K/AKT/mTOR signal pathway. These results clarify the role of STIM1 in HBZY-1 cells and its mechanism, and provide a new target for the treatment of DN.

Association of HTRA1 and CFH gene polymorphisms with age-related macular degeneration in Ningbo, China.

BACKGROUND: Age-related macular degeneration (AMD) is one of the major causes of blindness, and the incidence of this disease has been increasing in recent years. OBJECTIVE: To investigate the association between the single nucleotide polymorphisms (SNPs) of the high temperature requirement factor A-1 (HTRA1) and complement factor H (CFH) genes and susceptibility to AMD in Ningbo, China. METHODS: Ninety-eight patients with AMD and seventy-three controls were recruited at the Sixth Hospital of Ningbo from August 2017 to April 2019 in China. Genomic DNA was extracted from the venous blood provided by the hospital, and the genotypes of the AMD susceptibility genes CFH and HTAR1 were detected by polymerase chain reaction and sequenced directly. The SNPs rs11200638 on the HTRA1 gene and rs3753394 on the CFH gene were selected for genotype and association analysis. The correlations between the different genotypes of HTRA1 and CFH and AMD were analysed by the Chi-squared test. RESULTS: All the genotypes adhered to the Hardy-Weinberg equilibrium. There were three genotypes (AA, AG and GG) in HTRA1 (rs11200638). The differences in genotypes and allele frequency between the AMD group and the control group were statistically significant (P < 0.05). The A allele was a risk allele (OR: 4.19, 95% Cl: 2.28 ~ 7.70, P < 0.05), with a frequency of 61.7% in patients versus 43.8% in controls. However, the rs3753394 SNP in CFH was not associated with AMD in our study (P > 0.05). CONCLUSIONS: The rs11200638 SNP of the HTRA1 gene is associated with AMD, and the AA genotype is a risk factor for AMD in the Ningbo population. There is no significant correlation between the rs3753394 SNP of the CFH gene and AMD.

Major contribution of the 3/6/7 class of TRPC channels to myocardial ischemia/reperfusion and cellular hypoxia/reoxygenation injuries.

The injury phase after myocardial infarcts occurs during reperfusion and is a consequence of calcium release from internal stores combined with calcium entry, leading to cell death by apoptopic and necrotic processes. The mechanism(s) by which calcium enters cells has(ve) not been identified. Here, we identify canonical transient receptor potential channels (TRPC) 3 and 6 as the cation channels through which most of the damaging calcium enters cells to trigger their death, and we describe mechanisms activated during the injury phase. Working in vitro with H9c2 cardiomyoblasts subjected to 9-h hypoxia followed by 6-h reoxygenation (H/R), and analyzing changes occurring in areas-at-risk (AARs) of murine hearts subjected to a 30-min ischemia followed by 24-h reperfusion (I/R) protocol, we found: (i) that blocking TRPC with SKF96365 significantly ameliorated damage induced by H/R, including development of the mitochondrial permeability transition and proapoptotic changes in Bcl2/BAX ratios; and (ii) that AAR tissues had increased TUNEL+ cells, augmented Bcl2/BAX ratios, and increased p(S240)NFATc3, p(S473)AKT, p(S9)GSK3ß, and TRPC3 and -6 proteins, consistent with activation of a positive-feedback loop in which calcium entering through TRPCs activates calcineurin-mediated NFATc3-directed transcription of TRPC genes, leading to more Ca2+ entry. All these changes were markedly reduced in mice lacking TRPC3, -6, and -7. The changes caused by I/R in AAR tissues were matched by those seen after H/R in cardiomyoblasts in all aspects except for p-AKT and p-GSK3ß, which were decreased after H/R in cardiomyoblasts instead of increased. TRPC should be promising targets for pharmacologic intervention after cardiac infarcts.

TDCPP protects cardiomyocytes from H2O2-induced injuries via activating PI3K/Akt/GSK3ß signaling pathway.

Tris (1, 3-dichloro-2-propyl) phosphate (TDCPP) is a major type of organophosphorus flame retardants, and long-term exposure to TDCPP to normal cells or tissues under physiological conditions can induce toxic effects. But how TDCPP leads to the adverse effects is not yet clear, and the effect of TDCPP under pathological conditions such as reactive oxygen species assault is not well understood. The present study aimed to explore the potential effect of TDCPP against H2O2-induced oxidative stress in H9c2 cardiomyoblasts and rat neonatal cardiomyocytes. We found that H2O2-treatment decreased cell viability and increased lactate dehydrogenase and malondialdehyde generation of H9c2 cells. However, TDCPP could alleviate these effects. TDCPP alleviated Ca2+-overload caused by H2O2 through decreasing store-operated calcium entry. More importantly, TDCPP remarkably decreased H2O2-induced dephosphorylation of Akt and GSK3ß, and through this pathway TDCPP mitigated the H2O2-induced apoptosis and detrimental autophagy. Collectively, via mitigating Ca2+-overload and activating the Akt/GSK3ß signaling pathway, TDCPP may have a role in protecting cardiomyocytes from oxidative stress.

TDCPP protects cardiomyocytes from hypoxia-reoxygenation injury induced apoptosis through mitigating calcium overload and promotion GSK-3ß phosphorylation.

TDCPP, Tris (1, 3-dichloro-2-propyl) phosphate belongs to a group of chemicals known as triester organophosphate flame retardants, It can alter calcium homeostasis at much lower concentrations in normal conditions, but the mechanism is unclear till now. Calcium overload is a leading cause of apoptosis in myocardial ischemia/reperfusion (I/R) injury, thus how to mitigate Ca2+-overload is deserved to be investigated. We therefore hypothesized that TDCPP could attenuate cardiomyocytes apoptosis in I/R injury. H/R (hypoxia/reoxygenation) experiments in vitro were used to simulate in vivo I/R injury. The present study aimed to explore the potential effect of TDCPP in cardiomyocytes after H/R injury, Ca2+ imaging technique was used to explore SOCE(store-operated calcium entry) and Ca2+-overload levels, western blot technique was used to explore the potential target, the cell morphology, cell viability and mitochondrial membrane potential were also detected. The results have shown that: TDCPP could decrease SOCE, restore H9c2 cell viability, mitigate Ca2+-overload in H/R injury and reduce the mitochondrial membrane potential. Furthermore, TDCPP decreased STIM1 expression and promoted GSK3ß phosphorylation. Collectively, for the first time, this study suggest the antiapoptosis roles of TDCPP in H/R injury are via mitigation Ca2+-overload and promoting GSK-3ß phosphorylation.

Down-regulation of IFITM1 and its growth inhibitory role in cervical squamous cell carcinoma.

BACKGROUND: Cervical cancer is a major cause of death in women worldwide. Interferon-induced transmembrane protein 1 (IFITM1) is involved in antivirus defense, cell adhesion, and carcinogenesis in different tissues. However, the role of IFITM1 gene in cervical squamous cell cancer is unclear. METHODS: To explore the role of IFITM1 in carcinogenesis of cervical cancer, we investigated the expression of IFITM1 gene in cervical squamous cell carcinoma. IFITM1 mRNA level was measured by real-time quantitative RT-PCR in cervical cancer tissues and their adjacent normal tissues. IFITM1 protein level was measured by immunohistochemistry. Methylation in the IFITM1 gene promoter was detected by methylation-specific PCR. We then transfected HeLa cells with IFITM1 expression vector or control vector. IFITM1 expression was examined; cell migration and invasion were analyzed by wound healing assay and matrigel-coated transwell migration assays, respectively. HeLa cell proliferation was measured by cell counting kit-8 assay and cell cycle analysis. Cell apoptosis was analyzed by Annexin V/propidium iodide double staining assay. RESULTS: The difference in IFITM1 protein expression between samples from chronic cervicitis and cervical carcinoma was statistically significant (P < 0.01). Ki-67 and PCNA protein expression levels were significantly higher in cervical cancer tissues than in their corresponding cervicitis tissues (P < 0.05 and P < 0.001, respectively). IFITM1 mRNA level was significantly lower in cervical cancer tissues than in normal cervical tissues (P < 0.05). Methylation of the IFITM1 gene promoter was significantly higher in cervical cancer than in normal cervical tissues (P < 0.05). Transfection of the IFITM1 pcDNA3.1 construct decreased cell migration and invasion of HeLa cells, inhibited cell proliferation, and increased cell apoptosis. CONCLUSION: IFITM1 gene expression may reduce the proliferation, migration, and invasion of cervical squamous cancer cells.

The TRPC family of TRP channels: roles inferred (mostly) from knockout mice and relationship to ORAI proteins.

Aside from entering into cells through voltage gated Ca channels and Na/Ca exchangers in those cells that express these proteins, for all cells be they excitable or non-excitable, Ca(2+) enters through channels that are activated downstream of phosphoinositide mobilization (activation of phospholipase C, PLC) and through channels that are activated secondary to depletion of internal stores. Depletion of internal stores activates plasma membrane channels known as ORAIs. Activation of PLCs activates the canonical class of transient receptor potential channels (TRPCs), and, because this activation also causes depletion of Ca(2+) stores, also ORAI based channels. Whereas the activation of ORAI is a well-accepted phenomenon, it appears that TRPC channels also participate in Ca(2+) entry triggered by store depletion with or without participation of ORAI molecules. Regardless of molecular makeup of TRPC containing channels, a plethora of studies have shown TRPCs to be important both in physiologic systems as well as in pathophysiologic phenomena. Particularly important in defining roles of TRPCs, have been studies with mice with targeted disruption of their genes, i.e., with TRPC KO mice. In this chapter we first focus on TRPCs as regulators of body functions in health and disease, and then focus on the possible make-up of the channels of which they participate. A hypothesis is set forth, whereby ORAI dimers are proposed to be regulatory subunits of tetrameric TRPC channels and serve as structural units that form ORAI channels either as dimers of dimers or trimers of dimers.

TRPC6 Knockout Alleviates Renal Fibrosis through PI3K/AKT/GSK3B Pathway.

OBJECTIVE: Renal fibrosis is the ultimate pathway of various forms of acute and chronic kidney damage. Notably, the knockout of transient receptor potential channel 6 (TRPC6) has shown promise in alleviating renal fibrosis. However, the regulatory impact of TRPC6 on renal fibrosis remains unclear. METHODS: In vivo, TRPC6 knockout (TRPC6-/-) mice and age-matched 129 SvEv (WT) mice underwent unilateral renal ischemia-reperfusion (uIR) injury surgery on the left renal pedicle or sham operation. Kidneys and serum were collected on days 7, 14, 21, and 28 after euthanasia. In vitro, primary tubular epithelial cells (PTECs) were isolated from TRPC6-/- and WT mice, followed by treatment with transforming growth factor ß1 (TGFß1) for 72 h. The anti-fibrotic effect of TRPC6-/- and the underlying mechanisms were assessed through hematoxylin-eosin staining, Masson staining, immunostaining, qRT-PCR, and Western blotting. RESULTS: Increased TRPC6 expression was observed in uIR mice and PTECs treated with TGFß1. TRPC6-/- alleviated renal fibrosis by reducing the expression of fibrotic markers (Col-1, α-SMA, and vimentin), as well as decreasing the apoptosis and inflammation of PTECs during fibrotic progression both in vivo and in vitro. Additionally, we found that the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3 beta (GSK3ß) signaling pathway, a pivotal player in renal fibrosis, was down-regulated following TRPC6 deletion. CONCLUSION: These results suggest that the ablation of TRPC6 may mitigate renal fibrosis by inhibiting the apoptosis and inflammation of PTECs through down-regulation of the PI3K/AKT/GSK3ß pathway. Targeting TRPC6 could be a novel therapeutic strategy for preventing chronic kidney disease.

UsIL-6: An unbalanced learning strategy for identifying IL-6 inducing peptides by undersampling technique.

BACKGROUND AND OBJECTIVE: Interleukin-6 (IL-6) is the critical factor of early warning, monitoring, and prognosis in the inflammatory storm of COVID-19 cases. IL-6 inducing peptides, which can induce cytokine IL-6 production, are very important for the development of diagnosis and immunotherapy. Although the existing methods have some success in predicting IL-6 inducing peptides, there is still room for improvement in the performance of these models in practical application. METHODS: In this study, we proposed UsIL-6, a high-performance bioinformatics tool for identifying IL-6 inducing peptides. First, we extracted five groups of physicochemical properties and sequence structural information from IL-6 inducing peptide sequences, and obtained a 636-dimensional feature vector, we also employed NearMiss3 undersampling method and normalization method StandardScaler to process the data. Then, a 40-dimensional optimal feature vector was obtained by Boruta feature selection method. Finally, we combined this feature vector with extreme randomization tree classifier to build the final model UsIL-6. RESULTS: The AUC value of UsIL-6 on the independent test dataset was 0.87, and the BACC value was 0.808, which indicated that UsIL-6 had better performance than the existing methods in IL-6 inducing peptide recognition. CONCLUSIONS: The performance comparison on independent test dataset confirmed that UsIL-6 could achieve the highest performance, best robustness, and most excellent generalization ability. We hope that UsIL-6 will become a valuable method to identify, annotate and characterize new IL-6 inducing peptides.

PACVP: Prediction of Anti-Coronavirus Peptides Using a Stacking Learning Strategy With Effective Feature Representation.

Due to the global outbreak of COVID-19 and its variants, antiviral peptides with anti-coronavirus activity (ACVPs) represent a promising new drug candidate for the treatment of coronavirus infection. At present, several computational tools have been developed to identify ACVPs, but the overall prediction performance is still not enough to meet the actual therapeutic application. In this study, we constructed an efficient and reliable prediction model PACVP (Prediction of Anti-CoronaVirus Peptides) for identifying ACVPs based on effective feature representation and a two-layer stacking learning framework. In the first layer, we use nine feature encoding methods with different feature representation angles to characterize the rich sequence information and fuse them into a feature matrix. Secondly, data normalization and unbalanced data processing are carried out. Next, 12 baseline models are constructed by combining three feature selection methods and four machine learning classification algorithms. In the second layer, we input the optimal probability features into the logistic regression algorithm (LR) to train the final model PACVP. The experiments show that PACVP achieves favorable prediction performance on independent test dataset, with ACC of 0.9208 and AUC of 0.9465. We hope that PACVP will become a useful method for identifying, annotating and characterizing novel ACVPs.

Nintedanib induces apoptosis in human pterygium cells through the FGFR2-ERK signalling pathway.

AIM: To investigate whether nintedanib can inhibit pterygium cells through the fibroblast growth factor receptor 2 (FGFR2)/extracellular-signal-regulated kinase (ERK) pathway. METHODS: Human primary pterygium cells were cultured in vitro. After treatment with nintedanib, the cell morphology was observed under microscopy, the morphological changes of the nucleus were observed after DAPI staining, apoptosis was analyzed by Annexin-V FITC/PI double staining, and the changes of apoptosis-associated proteins were detected by Western blot. The binding ability of nintedanib to FGFR2 was predicted by molecular docking. Finally, by silencing FGFR2, we explored whether nintedanib inhibited FGFR2/ERK pathway. RESULTS: The results showed that nintedanib inhibited the growth of pterygium cells and caused nuclear pyknosis. The results of Annexin-VFITC/PI double staining showed that nintedanib was able to induce early and late apoptosis of pterygium cells, significantly increasing the expression of apoptosis-associated proteins Bax and cleaved-Caspase3 (P<0.05), and reducing the expression of Bcl-2 (P<0.05). In addition, nintedanib significantly inhibited ERK1/2 phosphorylation through FGFR2 (P<0.05). After silencing the expression of FGFR2, there was no significant difference in the inhibition of ERK1/2 phosphorylation by nintedanib (P>0.05). CONCLUSION: Nintedanib induces apoptosis of pterygium cells by inhibiting FGFR2/ERK pathway.

A sutureless technique for securing leaking sclerotomies with viscoelastic substances in 23-gauge microincision vitrectomy surgery.

AIM: To introduce and evaluate the clinical efficacy of a new technique, the use of viscoelastic substances (VS) to close leaking sclerotomy in 23G microincision vitrectomy, and to observe its effect on the visual acuity and intraocular pressure (IOP) of patients. METHODS: Patients who underwent 23G vitrectomy in Ningbo Eye Hospital before the use of VS technique (June 2019 to September 2020) and after the use of VS technique (October 2020 to December 2021) were selected as the subjects of this study. The above cases underwent operation by the same surgeon and were retrospectively analyzed. VS technique was used as the alternative to suturing, in which a small amount of VS was injected at the leaking sclerotomy and then gently massaged to confirm leaking sclerotomy closure. RESULTS: A total of 174 eyes were covered in the study, including 84 eyes in the control group (before the use of VS technique) and 90 eyes in the VS technique group. The number of eyes that needed to be sutured decreased considerably from 42.9% in the control group to 3.3% in the VS technique group, and the proportion of subconjunctival hemorrhage at 1-2d after surgery decreased remarkably from 35.7% in the control group to 2.2% in the VS technique group. No substantial differences in the incidence of mean IOP and low IOP were found between 1-2 and 3-20d after surgery in the VS technique group. No major complications associated with VS technique were identified during the study. CONCLUSION: In 23G microincision vitrectomy, VS technique is a safe, simple, and effective method to close leaking sclerotomy.

A role for Orai in TRPC-mediated Ca2+ entry suggests that a TRPC:Orai complex may mediate store and receptor operated Ca2+ entry.

TRPC and Orai proteins have both been proposed to form Ca(2+)-selective, store-operated calcium entry (SOCE) channels that are activated by store-depletion with Ca(2+) chelators or calcium pump inhibitors. In contrast, only TRPC proteins have been proposed to form nonselective receptor-operated calcium entry (ROCE) cation channels that are activated by Gq/Gi-PLCbeta signaling, which is the physiological stimulus for store depletion. We reported previously that a dominant negative Orai1 mutant, R91W, inhibits Ca(2+) entry through both SOCE and ROCE channels, implicating Orai participation in both channel complexes. However, the argument for Orai participating in ROCE independently of store depletion is tenuous because store depletion is an integral component of the ROCE response, which includes formation of IP3, a store-depleting agent. Here we show that the R91W mutant also blocks diacylglycerol (DAG)-activated Ca(2+) entry into cells that stably, or transiently, express DAG-responsive TRPC proteins. This strongly suggests that Orai and TRPC proteins form complexes that participate in Ca(2+) entry with or without activation of store depletion. To integrate these results with recent data linking SOCE with recruitment of Orai and TRPCs to lipid rafts by STIM, we develop the hypothesis that Orai:TRPC complexes recruited to lipid rafts mediate SOCE, whereas the same complexes mediate ROCE when they are outside of lipid rafts. It remains to be determined whether the molecules forming the permeation pathway are the same when Orai:TRPC complexes mediate ROCE or SOCE.

Application Research of Artificial Intelligence Screening System for Diabetic Retinopathy.

According to the latest data from the Bureau of Disease Control and Prevention of the National Health and Family Planning Commission, China currently has 199.6 million diabetic patients and has become the world's largest country with diabetes. The prevalence rate is as high as 14.3%, which is much higher than the world average of 5.8%. The primary-level ophthalmic screening service is one of the important tasks to improve primary-level medical services, and the corresponding ophthalmic imaging diagnosis technology is an important support for primary-level medical and health services. Therefore, it is very necessary for us to study the application of artificial intelligence image recognition technology for diabetic retinopathy under the medical consortium mode and to study the precise initial diagnosis, precise referral, and precise follow-up of diabetic retina under the medical conjoined mode, so as to better promote the transformation of the ophthalmology primary service model. Based on this background, in this article, we have proposed and carried out the following solution: (1) diabetes data collation. Based on medical artificial intelligence technology, this paper collected 2,265 electronic medical records from an eye hospital in Ningbo and selected 2,000 qualified medical records for data integration and preprocessing. The contents of electronic medical records mainly include age, gender, and examination records. (2) Establish diabetic retinopathy diagnosis model based on neural network algorithm. This article first uses the classic algorithm of BP neural network for modeling, chooses the Levenberg-Marquardt method as the training function, and selects 10 hidden layer units through comparison experiments. After that, ophthalmologists assessed 80 sets of test results and determined the right diagnosis rate. Finally, this article compares and analyzes the accuracy of the two routes in 80 tests.

Functional interactions among Orai1, TRPCs, and STIM1 suggest a STIM-regulated heteromeric Orai/TRPC model for SOCE/Icrac channels.

Receptor-operated Ca(2+) entry (ROCE) and store-operated Ca(2+) entry (SOCE) into cells are functions performed by all higher eukaryotic cells, and their impairment is life-threatening. The main molecular components of this pathway appear to be known. However, the molecular make-up of channels mediating ROCE and SOCE is largely unknown. One hypothesis proposes SOCE channels to be formed solely by Orai proteins. Another proposes SOCE channels to be composed of both Orai and C-type transient receptor potential (TRPC) proteins. Both hypotheses propose that the channels are activated by STIM1, a sensor of the filling state of the Ca(2+) stores that activates Ca(2+) entry when stores are depleted. The role of Orai in SOCE has been proven. Here we show the TRPC-dependent reconstitution of Icrac, the electrophysiological correlate to SOCE, by expression of Orai1; we also show that R91W-Orai1 can inhibit SOCE and ROCE and that Orai1 and STIM1 expression leads to functional expression of Gd-resistant ROCE. Because channels that mediate ROCE are accepted to be formed with the participation of TRPCs, our data show functional interaction between ROCE and SOCE components. We propose that SOCE/Icrac channels are composed of heteromeric complexes that include TRPCs and Orai proteins.

Changes of plasma nitric oxide, endothelin-1, and blood coagulation following intravitreal conbercept.

Intravitreal anti-VEGF (anti-vascular endothelial growth factor) biologics have revolutionized the pharmacological management of chorioretinal diseases. However, the systemic adverse events such as stroke or bleeding are the concerns for many patients and physicians. The mechanism to develop these side effects are poorly understood. Consecutive 95 patients with retinal diseases were studied for their blood activated partial thromboplastin time (APTT), prothrombin time (PT), international normalized ratio (INR), and concentration of fibrinogen before and after intravitreal conbercept. Additionally, plasma nitric oxide (NO) and endothelin-1 (ET-1) were investigated on 38 of the 95 patients. Compared with the pre-injection, 4-week post-injection values of APTT and PT were increased by 0.582 s (p = 0.038, paired t test) and by 0.086 s (p = 0.080, paired t test; p = 0.0475, Sign test), respectively. At the same time, fibrinogen decreased by 0.048 g/L. Plasma levels of NO or ET-1 or VEGF did not significantly change from pre-injection levels. Our findings advanced the understanding of mechanism for systemic side effects associated with intravitreal anti-VEGF and emphasized paying more attention to higher risk of possible bleedings for patients following intravitreal conbercept.

The Role of TRPC6 in Renal Ischemia/Reperfusion and Cellular Hypoxia/Reoxygenation Injuries.

Renal ischemia/reperfusion (I/R), a major cause of acute kidney injury (AKI), is a serious clinical event in patients during post-renal transplantation. I/R is associated with renal dysfunction and tubular apoptosis, and calcium (Ca2+) overload has been reported to be a crucial factor on tubular apoptosis in I/R injury (IRI). The canonical transient receptor potential channel 6 (TRPC6), a type of non-selective Ca2+ channel, is involved in many renal diseases. Our earlier study identified that TRPC6-mediated Ca2+ influx plays a novel role in suppressing cytoprotective autophagy triggered by oxidative stress in primary tubular epithelial cells (TECs). This study explored the potential beneficial impact of TRPC6 knockout (TRPC6-/-) and the relevant cellular mechanisms against I/R-induced AKI in mice. Measuring changes of renal function, apoptotic index, and autophagy in mouse kidneys that suffered 24 h reperfusion after 40 min ischemia and working in vitro with TECs that suffered 24 h reoxygenation after 24 h hypoxia, we found that 1) IRI tissues had increased TRPC6 expression and TRPC6 knockout significantly ameliorated renal damage induced by IRI; 2) TRPC6 knockout enhanced the level of autophagy and alleviated the depolarization of mitochondrial membrane potential (ψm, MMP) and apoptotic changes upon IRI; and 3) IRI tissues had increased p-AKT and p-ERK1/2 expressions, while TRPC6 knockout could markedly reduce the phosphorylation of AKT and ERK1/2. These discoveries suggest that, by reducing Ca2+ overload, the underlying protective mechanism of TRPC6-/- may be involved in down-regulation of PI3K/AKT and ERK signaling, which is likely to provide a new avenue for future AKI therapies.

Correlations of SDF-1 and CXCR4 levels with caspase-3 expression in the retina of rats after optic nerve injury.

OBJECTIVE: This study explores the correlations of stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) levels with caspase-3 expression in the retina of rats after optic nerve injury. MATERIALS AND METHODS: A total of 24 adult healthy specific pathogen-free Sprague-Dawley rats were selected and randomly divided into an optic nerve injury group (n=16) and an optic nerve sham-injury group (n=8). The optic nerve injury group was further sub-divided into a 3 d group (n=8) and a 7 d group (n=8) after their injuries. In the optic nerve injury group, the left eye of each rat was removed and prepared for the optic nerve injury model using the optic nerve clamping method. In the sham-injury group, the optic nerve in the left eye was only exposed without being clamped. The rats were sacrificed at 3 d and 7 d after their optic nerve injuries, and the retina was isolated. The expressions of SDF-1, CXCR4, and caspase-3 in the retina of the rats in each group were measured using an immunohistochemical method. Messenger ribonucleic acid (mRNA) and the protein expressions of SDF-1, CXCR4, and caspase-3 (cleaved caspase-3) in the retinas of rats were measured using quantitative real-time polymerase chain reaction (qPCR) and western blotting, respectively. Moreover, the correlations of the expression of SDF-1 and CXCR4 with caspase-3 expression were analyzed using the Spearman method. The apoptosis of retinal ganglion cells of rats in each group was observed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. RESULTS: Immunohistochemistry of the retinas revealed that, compared with those in the sham-injury group, the expressions of SDF-1 and CXCR4 in the retina in the 3 d group and the 7 d group were gradually increased. Caspase-3 expression was significantly elevated at 3 d after the injuries, but obviously decreased at 7 d after the injuries. The results of qPCR showed that the relative expression levels of SDF-1 and CXCR4 mRNA in the retina at 3 d and 7 d after optic nerve injuries were also significantly higher than those in the sham-injury group (P<0.01), and the caspase-3 mRNA expression was initially increased at 3 d but reduced at 7 d after the injuries (P<0.01). Western blotting for the detection of the SDF-1, CXCR4 and caspase-3 proteins indicated changes similar to those of the qPCR. Spearman analysis results demonstrated that there was a positive correlation between the SDF-1 and CXCR4 expressions, but the expressions of SDF-1 and CXCR4 had negative correlations with caspase-3 expression. TUNEL staining showed that apoptosis of the retinal cells was increased in the 3 d group but significantly decreased in the 7 d group. CONCLUSION: After optic nerve injury, the continuous increase of the SDF-1 and CXCR4 levels suppresses the apoptosis of retinal cells and repairs the retina by inhibiting the cleavage activation of caspase-3. This provides new insights for the ongoing treatment of optic nerve injury.

Functional coupling between BKCa and SOC channels.

High-conductance, voltage- and calcium-activated potassium channels (BKCa) and store-operated calcium channels (SOCs) are belong to K+ channels superfamily and calcium channels superfamily respectively. Since BKCa potassium channels can be activated by calcium ions, we set out to examine whether SOCs are coupled with BKCa and to probe the relationship of BKCa and SOCs. First, we proved that BKCa immunoprecipitated with Orai1, and confocal microscopy showed that BKCa co-localized with Orai1. Next, we mapped that the exact binding sites locate in the 350aa-371aa fragment of the first regulatory domain associated with K+ conduction (RCK1) and the 720aa-814aa fragment in the second regulatory domain associated with K+ conduction (RCK2) via GST-pull-down assays. Then, we showed, by calcium imaging that BKCa overexpression enhanced endogenous and exogenous store-operated calcium entry (SOCE) and this enhancement could be blocked by Orai1 knockdown. Finally, we proved that SOCE could enhance the activity of BKCa by patch-clamp. From these results we conclude that BKCa can form a positive feedback loop with SOCs, as the Ca2+ influx from SOCs can active BKCa, which can hyperpolarize the plasma membrane. In turn, the hyperpolarized membrane will form a higher electric potential difference and give more force, allowing Ca2+ influx via SOCs.