An aptasensor for rapid and sensitive detection of estrogen receptor alpha in human breast cancer

The analysis of estrogen receptor (ER) expression in breast carcinomas plays a crucial role in determining the endocrine responsiveness of tumors for systemic adjuvant therapy. Conventionally, the ER levels in breast carcinomas had been detected using the dextran-coated charcoal assay and radioimmunoassay, which are now substituted with safer and economic antibody-based assays such as immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA). Despite a gold (Au) standard method, the IHC has been criticized for factors such as tissue fixation, antibody selection, and threshold staining for result interpretation that could falsify test accuracy and reproducibility. The quest for alternative methods of ER quantification in tissue samples paved the way for aptamer-based diagnostics. Previously, we have isolated a DNA aptamer against human ER alpha (ERα) using an in vitro evolution system. In this study, we developed an electrochemical sensor using the 76-nucleotide DNA ERα- aptamer for rapid, precise, and cost-effective detection of ERα expression in human breast cancer patients. The aptasensor was constructed by covalently immobilizing the thiolated ERα- aptamer onto a screen-printed Au electrode. Construction of aptasensors was confirmed through atomic force microscopy and differential pulse voltammetry measurements. A detection limit of 0.001 ng/ml was calculated for full-length ERα (66.2 kDa) in a detection time of 10 min. Analysis of the cancerous breast tissue samples using the ELISA and aptasensor methods enabled distinctive classification of samples into the categories of ER −ve, weak ER +ve, and strong ER +ve samples. The current change of this aptasensor lies within 5% after a storage of 60 days at 4°C. Further studies on a reasonably large sample size are required to realize the clinical potential of the sensor.     

The multifaceted role of TMEM16A in cancer

The calcium-activated chloride channel TMEM16A is intimately linked to cancers. Over decades, TMEM16A over-expression and contribution to prognosis have been widely studied for multiple cancers strengthening the idea that TMEM16A could be a valuable biomarker and a promising therapeutic target. Surprisingly, from the survey of the literature, it appears that TMEM16A has been involved in multiple cancer-related functions and a large number of molecular targets of TMEM16A have been proposed. Thus, TMEM16A appears to be an ion channel with a multifaceted role in cancers.In this review, we summarize the latest development regarding TMEM16A contribution to cancers. We will survey TMEM16A contribution in cancer prognosis, the origins of its over-expression in cancer cells, the multiple biological functions and molecular pathways regulated by TMEM16A. Then, we will consider the question regarding the molecular mechanism of TMEM16A in cancers and the possible basis for the multifaceted role of TMEM16A in cancers.     

Impaired renal organic anion transport 1 (SLC22A6) and its regulation following acute myocardial infarction and reperfusion injury in rats

Acute kidney injury (AKI) is a high frequent and common complication following acute myocardial infarction (AMI). This study examined and identified the effect of AMI-induced AKI on organic anion transporter 1 (Oat1) and Oat3 transport using clinical setting of pre-renal AKI in vivo. Cardiac ischaemia (CI) and cardiac ischaemia and reperfusion (CIR) were induced in rats by 30-min left anterior descending coronary artery occlusion and 30-min occlusion followed by 120-min reperfusion, respectively. Renal hemodynamic parameters, mitochondrial function and Oat1/Oat3 expression and function were determined along with biochemical markers. Results showed that CI markedly reduced renal blood flow and pressure by approximately 40%, while these parameters were recovered during reperfusion. CI and CIR progressively attenuated renal function and induced oxidative stress by increasing plasma BUN, creatinine and malondialdehyde levels. Correspondingly, SOD, GPx, CAT mRNAs were decreased, while TNFα, IL1β, COX2, iNOS, NOX2, NOX4, and xanthine oxidase were increased. Mitochondrial dysfunction as indicated by increasing ROS, membrane depolarisation, swelling and caspase3 activation were shown. Early significant detection of AKI; KIM1, IL18, was found. All of which deteriorated para-aminohippurate transport by down-regulating Oat1 during sudden ischaemia. This consequent blunted the trafficking rate of Oat1/Oat3 transport via down-regulating PKCζ/Akt and up-regulating PKCα/NFκB during CI and CIR. Thus, this promising study indicates that CI and CIR abruptly impaired renal Oat1 and regulatory proteins of Oat1/Oat3, which supports dysregulation of remote sensing and signalling and inter-organ/organismal communication. Oat1, therefore, could potentially worsen AKI and might be a potential therapeutic target for early reversal of such injury.     

A comparison between the homocyclic aromatic metabolic pathways from plant-derived compounds by bacteria and fungi

Aromatic compounds derived from lignin are of great interest for renewable biotechnical applications. They can serve in many industries e.g. as biochemical building blocks for bioplastics or biofuels, or as antioxidants, flavor agents or food preservatives. In nature, lignin is degraded by microorganisms, which results in the release of homocyclic aromatic compounds. Homocyclic aromatic compounds can also be linked to polysaccharides, tannins and even found freely in plant biomass. As these compounds are often toxic to microbes already at low concentrations, they need to be degraded or converted to less toxic forms. Prior to ring cleavage, the plant- and lignin-derived aromatic compounds are converted to seven central ring-fission intermediates, i.e. catechol, protocatechuic acid, hydroxyquinol, hydroquinone, gentisic acid, gallic acid and pyrogallol through complex aromatic metabolic pathways and used as energy source in the tricarboxylic acid cycle. Over the decades, bacterial aromatic metabolism has been described in great detail. However, the studies on fungal aromatic pathways are scattered over different pathways and species, complicating a comprehensive view of fungal aromatic metabolism. In this review, we depicted the similarities and differences of the reported aromatic metabolic pathways in fungi and bacteria. Although both microorganisms share the main conversion routes, many alternative pathways are observed in fungi. Understanding the microbial aromatic metabolic pathways could lead to metabolic engineering for strain improvement and promote valorization of lignin and related aromatic compounds.     

Human p38α mitogen-activated protein kinase in the Asp168-Phe169-Gly170-in (DFG-in) state can bind allosteric inhibitor Doramapimod

Doramapimod (BIRB-796) is widely recognized as one of the most potent and selective type II inhibitors of human p38α mitogen-activated protein kinase (MAPK); however, the understanding of its binding mechanism remains incomplete. Previous studies indicated high affinity of the ligand to a so-called allosteric pocket revealed only in the ‘out’ state of the DFG motif (i.e. Asp168-Phe169-Gly170) when Phe169 becomes fully exposed to the solvent. The possibility of alternative binding in the DFG-in state was hypothesized, but the molecular mechanism was not known. Methods of bioinformatics, docking and long-time scale classical and accelerated molecular dynamics have been applied to study the interaction of Doramapimod with the human p38α MAPK. It was shown that Doramapimod can bind to the protein even when the Phe169 is fully buried inside the allosteric pocket and the kinase activation loop is in the DFG-in state. Orientation of the inhibitor in such a complex is significantly different from that in the known crystallographic complex formed by the kinase in the DFG-out state; however, the Doramapimod’s binding is followed by the ligand-induced conformational changes, which finally improve accommodation of the inhibitor. Molecular modelling has confirmed that Doramapimod combines the features of type I and II inhibitors of p38α MAPK, i.e. can directly and indirectly compete with the ATP binding. It can be concluded that optimization of the initial binding in the DFG-in state and the final accommodation in the DFG-out state should be both considered at designing novel efficient type II inhibitors of MAPK and homologous proteins.

Communicated by Ramaswamy H. Sarma     

Repression of let-7b-5p prevents the development of multifidus muscle dysfunction by promoting vitamin D accumulation via upregulation of electron transfer flavoprotein alpha subunit in a rat model of multifidus muscle injury

Multifidus muscle dysfunction is associated with the multifidus muscle injury (MMI), which ultimately result in the low-back pain. Increasing evidence shows that microRNAs (miRs) may be involved in multifidus muscle dysfunction. In this study, we tested the hypothesis that downregulation of let-7b-5p may inhibit the multifidus muscle dysfunction development and progression. The target prediction program and luciferase activity determination confirmed electron transfer flavoprotein alpha subunit (ETFA) as a direct target gene of let-7b-5p. To study the mechanisms and functions of let-7b-5p in relation to ETFA in MMI progression, we prepared rats with experimental MMI, and a lentivirus-based packaging system was designed to upregulate expressions of let-7b-5p, and downregulate the expression of ETFA. ETFA was identified as a target gene of let-7b-5p. Older age, a longer duration of pain, and higher visual analog scale and Oswestry disability index scores for the patients with chronic low-back pain were linked to a more severe degree of degenerative muscle atrophy and fatty infiltration. Increased expression of let-7b-5p and decreased expression of ETFA and vitamin D receptor (VDR) were positively correlated with multifidus muscle dysfunction. Downregulated let-7b-5p could inhibit infiltration of collagen fibers, reverse the ultrastructural changes of multifidus muscle, and induce the VDR expression, thereby repair the MMI. The results provided a potential basis for let-7b-5p that could support targeted intervention in multifidus muscle dysfunction. Collectively, this study confirmed that downregulation of let-7b-5p has a potential inhibitory effect on the development of the function of the musculus myocytes by upregulating ETFA.     

Effects of alpha lipoic acid and its derivative “andrographolid-lipoic acid-1” on ulcerative colitis: A systematic review with meta-analysis of animal studies

We aimed to review and meta-analyze the inflammatory and oxidative factors following alpha lipoic acid (ALA) and its derivative “andrographolid-lipoic acid-1” (AL-1) in ulcerative colitis (UC). ALA plays an important role in scavenging intracellular radicals and inflammatory elements. AL-1 is found in herbal medicines with potent anti-inflammatory properties. Data were collected from the Google Scholar, PubMed, Scopus, Evidence-based medicine/clinical trials, and Cochrane library database until 2017, which finally resulted in 22 animal studies (70 rats and 162 mice). The beneficial effects of ALA or AL-1 on the most important parameters of UC were reviewed; also, studies were considered separately in mice and rats. Administration of ALA and AL-1 significantly reduced the tumor necrosis factor-α level compared with the controls, while data were not noteworthy in the meta-analysis (mean differences = −18.57 [95% CI = −42.65 to 5.51], P = 0.13). In spite of insignificant decrease in meta-analysis outcomes (differences = 6.92 [95% CI = −39.33 to 53.16], P = 0.77), a significant reduction in myeloperoxidase activity was shown following ALA or AL-1 treatment compared with the controls. Despite significant differences in each study, we had to exclude some studies to homogenize data for meta-analyzing as they showed insignificant results. Interleukin 6, cyclooxygenase-2, glutathione, malondialdehyde, superoxide dismutase, histopathological score, macroscopic and microscopic scores, disease activity index, body weight change, and colon length were also reviewed. Most studies have emphasized on significant positive effects of ALA and AL-1. Comprehensive clinical trials are obligatory to determine the precious position of ALA or AL-1 in the management of UC.     

Proteoglycan 4 deficiency protects against glucose intolerance and fatty liver disease in diet-induced obese mice

Objective

Proteoglycan 4 (Prg4) has emerged from human association studies as a possible factor contributing to weight gain, dyslipidemia and insulin resistance. In the current study, we investigated the causal role of Prg4 in controlling lipid and glucose metabolism in mice.

Interaction of the NG2 proteoglycan with the actin cytoskeleton

The NG2 chondroitin sulfate proteoglycan is a membrane-spanning molecule expressed by immature precursor cells in a variety of developing tissues. In tightly adherent cell lines with a flattened morphology, NG2 is organized on the cell surface in linear arrays that are highly co-localized with actin and myosin-containing stress fibers in the cytoskeleton. In contrast, microtubules and intermediate filaments in the cytoskeleton exhibit completely different patterns of organization, suggesting that NG2 may use microfilamentous stress fibers as a means of cytoskeletal anchorage. Consistent with this is the observation that cytochalasin D disrupts the organization of both stress fibers in the cytoskeleton and NG2 on the cell surface. Very similar linear cell surface arrays are also seen with three other cell surface molecules thought to interact with the actin cytoskeleton: the α₅β₁ integrin, the CD44 proteoglycan, and the L1 neuronal cell adhesion molecule. Since the cytoplasmic domains of these four molecules are dissimilar, it seems possible that cytoskeletal anchorage in each case may occur via different mechanisms. One indication of such differences can be seen in colchicine-treated cells which have lost their flattened morphology but still retain long actin-positive tendrils as remnants of the actin cytoskeleton. NG2 and α₅β₁ are associated with these tendrils while CD44 and L1 are not, suggesting that at least two subclasses of cell surface molecules exist which can interact with different subdomains of the actin cytoskeleton. © 1996 Wiley-Liss, Inc.