Modulatory Effects of Curcumin on Redox Status,Mitochondrial Function,and Caspace‐3 Expression During Atrazin‐Induced Toxicity

Atrazine is currently the most widely used herbicide in agriculture with lots of adverse effects on human health. Curcumin is a polyphenol known for its antioxidant, anti‐inflammatory, and anticancer properties. In the present study, the protective effect of curcumin on atrazin‐intoxicated rats is evaluated. Toxicity was induced by oral administration of atrazine (400 mg/kg/day) for 3 weeks. Curcumin at a dose of 400 mg/kg/day was given simultaneously by oral route. Redox status, mitochondrial function, 8‐hydroxydeoxyguanosine (8‐OHdG) level by immunoassay, and caspace‐3 expression by immunohistochemistry were evaluated. Curcumin showed significant cardiac protection with improvement of redox status, mitochondrial function, 8‐OHdG level, caspase‐3 immunoreactivity, and cardiac muscle degeneration. From this current study, it can be concluded that administration of curcumin improved atrazine‐induced cardiotoxicity through its modulatory effect on redox status, mitochondrial function, and caspase‐3 expression.     

Heterojunction‐Depleted Lead‐Free Perovskite Solar Cells with Coarse‐Grained B‐γ‐CsSnI3 Thin Films

Perovskite solar cells (PSCs) have been emerging as a breakthrough photovoltaic technology, holding unprecedented promise for low‐cost, high‐efficiency renewable electricity generation. However, potential toxicity associated with the state‐of‐the‐art lead‐containing PSCs has become a major concern. The past research in the development of lead‐free PSCs has met with mixed success. Herein, the promise of coarse‐grained B‐γ‐CsSnI₃ perovskite thin films as light absorber for efficient lead‐free PSCs is demonstrated. Thermally‐driven solid‐state coarsening of B‐γ‐CsSnI₃ perovskite grains employed here is accompanied by an increase of tin‐vacancy concentration in their crystal structure, as supported by first‐principles calculations. The optimal device architecture for the efficient photovoltaic operation of these B‐γ‐CsSnI₃ thin films is identified through exploration of several device architectures. Via modulation of the B‐γ‐CsSnI₃ grain coarsening, together with the use of the optimal PSC architecture, planar heterojunction‐depleted B‐γ‐CsSnI₃ PSCs with power conversion efficiency up to 3.31% are achieved without the use of any additives. The demonstrated strategies provide guidelines and prospects for developing future high‐performance lead‐free PVs.     

Ischaemia‐related cell damage in extracorporeal preserved tissue – new findings with a novel perfusion model

Tissue undergoing free transfer in transplant or reconstructive surgery always is at high risk of ischaemia‐related cell damage. This study aims at assessing different procedures using an extracorporeal perfusion and oxygenation system to investigate the expression of hypoxia inducible factor (HIF)‐1‐α as marker for hypoxia and of the pro‐apoptotic protein Caspase‐3 in skeletal muscle to elucidate potential improvements in tissue conservation. Twenty‐four porcine rectus abdominis muscles were assigned to five different groups and examined after they had been extracorporeally preserved for 60 min. time. Group I was left untreated (control), group II was perfused with a cardioplegic solution, group III was flushed with 10 ml of a cardioplegic solution and then left untreated. Group IV and V were perfused and oxygenated with either an isotone crystalloid solution or a cardioplegic solution. Among others, immunohistochemistry (Caspase‐3 and HIF‐1‐α) of muscle samples was performed. Furthermore, oxygen partial pressure in the perfusate at the arterial and venous branch was measured. Expression of Caspase‐3 after 60 min. was reduced in all groups compared to the control group. Furthermore, all groups (except group III) expressed less HIF‐1‐α than the control group. Oxygenation leads to higher oxygen levels at the venous branch compared to groups without oxygenation. Using an extracorporeal perfusion and oxygenation system cell damage could be reduced as indicated by stabilized expressions of Caspase‐3 and HIF‐1‐α for 60 min. of tissue preservation. Complete depletion of oxygen at the venous branch can be prevented by oxygenation of the perfusate with ambient air.     

Slot‐Die and Roll‐to‐Roll Processed Single Junction Organic Photovoltaic Cells with the Highest Efficiency

The record efficiency of the state‐of‐the‐art polymer solar cells (PSCs) is rapidly increasing, due to the discovery of high‐performance photoactive donor and acceptor materials. However, strong questions remain as to whether such high‐efficiency PSCs can be produced by scalable processes. This paper reports a high power conversion efficiency (PCE) of 13.5% achieved with single‐junction ternary PSCs based on PTB7‐Th, PC₇₁BM, and COi8DFIC fabricated by slot‐die coating, which shows the highest PCE ever reported in PSCs fabricated by a scalable process. To understand the origin of the high performance of the slot‐die coated device, slot‐die coated photoactive films and devices are systematically investigated. These results indicate that the good performance of the slot‐die PSCs can be due to a favorable molecule‐structure and film‐morphology change by introducing 1,8‐diiodooctane and heat treatment, which can lead to improved charge transport with reduced carrier recombination. The optimized condition is then used for the fabrication of large‐area modules and also for roll‐to‐roll fabrication. The slot‐die coated module with 30 cm² active‐area and roll‐to‐roll produced flexible PSC has shown 8.6% and 9.6%, respectively. These efficiencies are the highest in each category and demonstrate the strong potential of the slot‐die coated ternary system for commercial applications.     

IL‐12 stimulates the osteoclast inhibitory peptide‐1 (OIP‐1/hSca) gene expression in CD4+ T cells

Immune cell products such as interferon (IFN)‐γ and interleukin (IL)‐12 are potent inhibitors of osteoclast formation. We previously characterized the human osteoclast inhibitory peptide‐1 (OIP‐1/hSca), a Ly‐6 gene family member and showed IFN‐γ modulation of OIP‐1 expression in bone marrow cells. Whether, IL‐12 regulates OIP‐1 expression in the bone microenvironment is unclear. Real‐time PCR analysis revealed that IL‐12 treatment significantly enhanced OIP‐1 mRNA expression in human bone marrow mononuclear cells. Because IL‐12 induces IFN‐γ production by T cells, we tested whether IFN‐γ participates in IL‐12 stimulation of OIP‐1 gene expression in these cells. IL‐12 treatment in the presence of IFN‐γ neutralizing antibody significantly increased OIP‐1 mRNA expression, suggesting that IL‐12 directly regulates OIP‐1 gene expression. Interestingly, real‐time PCR analysis demonstrated that IL‐12 induces OIP‐1 expression (3.2‐fold) in CD4+ T cells; however, there was no significant change in CD8+ T cells. Also, IL‐12 (10 ng/ml) treatment of Jurkat cells transfected with OIP‐1 gene (?1 to ?1,988 bp) promoter‐luciferase reporter plasmid demonstrated a 5‐fold and 2.7‐fold increase in OIP‐1 gene promoter activity in the presence and absence of antibody against IFN‐γ, respectively. We showed that STAT‐1,3 inhibitors treatment significantly decreased IL‐12 stimulated OIP‐1 promoter activity. Chromatin immunoprecipitation (ChIP) assay confirmed STAT‐3, but not STAT‐1 binding to the OIP‐1 gene promoter in response to IL‐12 stimulation. These results suggest that IL‐12 stimulates the OIP‐1 gene expression through STAT‐3 activation in CD4+ T cells. J. Cell. Biochem. 107: 104–111, 2009. © 2009 Wiley‐Liss, Inc.     

Interleukin‐6 contributes to chemoresistance in MDA‐MB‐231 cells via targeting HIF‐1α

Chemoresistance is a critical challenge in the clinical treatment of triple‐negative breast cancer (TNBC). It has been well documented that inflammatory mediators from tumor microenvironment are involved in the pathogenesis of TNBC and might be related to chemoresistance of cancer cells. In this study, the contribution of interleukin‐6 (IL‐6), one of the principal oncogenic molecules, in chemoresistance of a TNBC cell line MDA‐MB‐231 was first investigated. The results showed that IL‐6 treatment could induce upregulation of HIF‐1α via the activation of STAT3 in MDA‐MB‐231 cells, which consequently contributed to its effect against chemotherapeutic drug‐induced cytotoxicity and cell apoptosis. However, knockdown of HIF‐1α attenuated such effect via affecting the expressions of apoptosis‐related molecules as Bax and Bcl‐2 and drug transporters as P‐gp and MRP1. This study indicated that targeting at IL‐6/HIF‐1α signaling pathway might be an effective strategy to overcome chemoresistance in TNBC therapy.     

Grb7 and Hax1 may colocalize partially to mitochondria in EGF‐treated SKBR3 cells and their interaction can affect Caspase3 cleavage of Hax1

Growth factor receptor bound protein 7 (Grb7) is a signal‐transducing adaptor protein that mediates specific protein–protein interactions in multiple signaling pathways. Grb7, with Grb10 and Grb14, is members of the Grb7 protein family. The topology of the Grb7 family members contains several protein‐binding domains that facilitate the formation of protein complexes, and high signal transduction efficiency. Grb7 has been found overexpressed in several types of cancers and cancer cell lines and is presumed involved in cancer progression through promotion of cell proliferation and migration via interactions with the erythroblastosis oncogene B 2 (human epidermal growth factor receptor 2) receptor, focal adhesion kinase, Ras‐GTPases, and other signaling partners. We previously reported Grb7 binds to Hax1 (HS1 associated protein X1) isoform 1, an anti‐apoptotic protein also involved in cell proliferation and calcium homeostasis. In this study, we confirm that the in vitro Grb7/Hax1 interaction is exclusive to these two proteins and their interaction does not depend on Grb7 dimerization state. In addition, we report Grb7 and Hax1 isoform 1 may colocalize partially to mitochondria in epidermal growth factor‐treated SKBR3 cells and growth conditions can affect this colocalization. Moreover, Grb7 can affect Caspase3 cleavage of Hax1 isoform 1 in vitro, and Grb7 expression may slow Caspase3 cleavage of Hax1 isoform 1 in apoptotic HeLa cells. Finally, Grb7 is shown to increase cell viability in apoptotic HeLa cells in a time‐dependent manner. Taken together, these discoveries provide clues for the role of a Grb7/Hax1 protein interaction in apoptosis pathways involving Hax1. Copyright © 2016 John Wiley & Sons, Ltd.     

Regulation of adipose‐tissue‐derived stromal cell orientation and motility in 2D‐ and 3D‐cultures by direct‐current electrical field

Cell alignment and motility play a critical role in a variety of cell behaviors, including cytoskeleton reorganization, membrane‐protein relocation, nuclear gene expression, and extracellular matrix remodeling. Direct current electric field (EF) in vitro can direct many types of cells to align vertically to EF vector. In this work, we investigated the effects of EF stimulation on rat adipose‐tissue‐derived stromal cells (ADSCs) in 2D‐culture on plastic culture dishes and in 3D‐culture on various scaffold materials, including collagen hydrogels, chitosan hydrogels and poly(L‐lactic acid)/gelatin electrospinning fibers. Rat ADSCs were exposed to various physiological‐strength EFs in a homemade EF‐bioreactor. Changes of morphology and movements of cells affected by applied EFs were evaluated by time‐lapse microphotography, and cell survival rates and intracellular calcium oscillations were also detected. Results showed that EF facilitated ADSC morphological changes, under 6 V/cm EF strength, and that ADSCs in 2D‐culture aligned vertically to EF vector and kept a good cell survival rate. In 3D‐culture, cell galvanotaxis responses were subject to the synergistic effect of applied EF and scaffold materials. Fast cell movement and intracellular calcium activities were observed in the cells of 3D‐culture. We believe our research will provide some experimental references for the future study in cell galvanotaxis behaviors.     

Dimer‐specific immunoprecipitation of active caspase‐2 identifies TRAF proteins as novel activators

Caspase‐2 has been shown to initiate apoptotic cell death in response to specific intracellular stressors such as DNA damage. However, the molecular mechanisms immediately upstream of its activation are still poorly understood. We combined a caspase‐2 bimolecular fluorescence complementation (BiFC) system with fluorophore‐specific immunoprecipitation to isolate and study the active caspase‐2 dimer and its interactome. Using this technique, we found that tumor necrosis factor receptor‐associated factor 2 (TRAF2), as well as TRAF1 and 3, directly binds to the active caspase‐2 dimer. TRAF2 in particular is necessary for caspase‐2 activation in response to apoptotic cell death stimuli. Furthermore, we found that dimerized caspase‐2 is ubiquitylated in a TRAF2‐dependent manner at K15, K152, and K153, which in turn stabilizes the active caspase‐2 dimer complex, promotes its association with an insoluble cellular fraction, and enhances its activity to fully commit the cell to apoptosis. Together, these data indicate that TRAF2 positively regulates caspase‐2 activation and consequent cell death by driving its activation through dimer‐stabilizing ubiquitylation.     

CircPSMC3 alleviates the symptoms of PCOS by sponging miR‐296‐3p and regulating PTEN expression

Polycystic ovary syndrome (PCOS), the most common female endocrine disease that causes anovulatory infertility, still lacks promising strategy for the accurate diagnosis and effective therapeutics of PCOS attributed to its unclear aetiology. In this study, we determined the abnormal reduction in circPSMC3 expression by comparing the ovarian tissue samples of PCOS patients and normal individuals. The symptom relief caused by up‐regulation of circPSMC3 in PCOS model mice suggested the potential for further study. In vitro functional experiments confirmed that circPSMC3 can inhibit cell proliferation and promote apoptosis by blocking the cell cycle in human‐like granular tumour cell lines. Mechanism study revealed that circPSMC3 may play its role through sponging miR‐296‐3p to regulate PTEN expression. Collectively, we preliminarily characterized the role and possible insights of circPSMC3/miR‐296‐3p/PTEN axis in the proliferation and apoptosis of KGN cells. We hope that this work provides some original and valuable information for the research of circRNAs in PCOS, not only to better understand the pathogenesis but also to help provide new clues for seeking for the future therapeutic target of PCOS.     

14‐3‐3 Proteins regulate K2P5.1 surface expression on T lymphocytes

K_2P5.1 channels (also called TASK‐2 or Kcnk5) have already been shown to be relevant in the pathophysiology of autoimmune disease because they are known to be upregulated on peripheral and central T lymphocytes of multiple sclerosis (MS) patients. Moreover, overexpression of K_2P5.1 channels in vitro provokes enhanced T‐cell effector functions. However, the molecular mechanisms regulating intracellular K_2P5.1 channel trafficking are unknown so far. Thus, the aim of the study is to elucidate the trafficking of K_2P5.1 channels on T lymphocytes. Using mass spectrometry analysis, we have identified 14‐3‐3 proteins as novel binding partners of K_2P5.1 channels. We show that a non‐classical 14‐3‐3 consensus motif (R‐X‐X‐pT/S‐x) at the channel's C‐terminus allows the binding between K_2P5.1 and 14‐3‐3. The mutant K_2P5.1/S266A diminishes the protein‐protein interaction and reduces the amplitude of membrane currents. Application of a non‐peptidic 14‐3‐3 inhibitor (BV02) significantly reduces the number of wild‐type channels in the plasma membrane, whereas the drug has no effect on the trafficking of the mutated channel. Furthermore, blocker application reduces T‐cell effector functions. Taken together, we demonstrate that 14‐3‐3 interacts with K_2P5.1 and plays an important role in channel trafficking.      

β‐arrestin2/miR‐155/GSK3β regulates transition of 5′‐azacytizine‐induced Sca‐1‐positive cells to cardiomyocytes

Stem‐cell antigen 1–positive (Sca‐1+) cardiac stem cells (CSCs), a vital kind of CSCs in humans, promote cardiac repair in vivo and can differentiate to cardiomyocytes with 5′‐azacytizine treatment in vitro. However, the underlying molecular mechanisms are unknown. β‐arrestin2 is an important scaffold protein and highly expressed in the heart. To explore the function of β‐arrestin2 in Sca‐1+ CSC differentiation, we used β‐arrestin2–knockout mice and overexpression strategies. Real‐time PCR revealed that β‐arrestin2 promoted 5′‐azacytizine‐induced Sca‐1+ CSC differentiation in vitro. Because the microRNA 155 (miR‐155) may regulate β‐arrestin2 expression, we detected its role and relationship with β‐arrestin2 and glycogen synthase kinase 3 (GSK3β), another probable target of miR‐155. Real‐time PCR revealed that miR‐155, inhibited by β‐arrestin2, impaired 5′‐azacytizine‐induced Sca‐1+ CSC differentiation. On luciferase report assay, miR‐155 could inhibit the activity of β‐arrestin2 and GSK3β, which suggests a loop pathway between miR‐155 and β‐arrestin2. Furthermore, β‐arrestin2‐knockout inhibited the activity of GSK3β. Akt, the upstream inhibitor of GSK3β, was inhibited in β‐arrestin2‐Knockout mice, so the activity of GSK3β was regulated by β‐arrestin2 not Akt. We transplanted Sca‐1+ CSCs from β‐arrestin2‐knockout mice to mice with myocardial infarction and found similar protective functions as in wild‐type mice but impaired arterial elastance. Furthermore, low level of β‐arrestin2 agreed with decreased phosphorylation of AKT and increased phophorylation of GSK3β, similar to in vitro findings. The β‐arrestin2/miR‐155/GSK3β pathway may be a new mechanism with implications for treatment of heart disease.