Prediction of cooperative homeodomain DNA binding sites from high-throughput-SELEX data.

Homeodomain proteins constitute one of the largest families of metazoan transcription factors. Genetic studies have demonstrated that homeodomain proteins regulate many developmental processes. Yet, biochemical data reveal that most bind highly similar DNA sequences. Defining how homeodomain proteins achieve DNA binding specificity has therefore been a long-standing goal. Here, we developed a novel computational approach to predict cooperative dimeric binding of homeodomain proteins using High-Throughput (HT) SELEX data. Importantly, we found that 15 of 88 homeodomain factors form cooperative homodimer complexes on DNA sites with precise spacing requirements. Approximately one third of the paired-like homeodomain proteins cooperatively bind palindromic sequences spaced 3 bp apart, whereas other homeodomain proteins cooperatively bind sites with distinct orientation and spacing requirements. Combining structural models of a paired-like factor with our cooperativity predictions identified key amino acid differences that help differentiate between cooperative and non-cooperative factors. Finally, we confirmed predicted cooperative dimer sites in vivo using available genomic data for a subset of factors. These findings demonstrate how HT-SELEX data can be computationally mined to predict cooperativity. In addition, the binding site spacing requirements of select homeodomain proteins provide a mechanism by which seemingly similar AT-rich DNA sequences can preferentially recruit specific homeodomain factors.

Scleraxis and fibrosis in the pressure-overloaded heart.

AIMS: In response to pro-fibrotic signals, scleraxis regulates cardiac fibroblast activation in vitro via transcriptional control of key fibrosis genes such as collagen and fibronectin; however, its role in vivo is unknown. The present study assessed the impact of scleraxis loss on fibroblast activation, cardiac fibrosis, and dysfunction in pressure overload-induced heart failure. METHODS AND RESULTS: Scleraxis expression was upregulated in the hearts of non-ischemic dilated cardiomyopathy patients, and in mice subjected to pressure overload by transverse aortic constriction (TAC). Tamoxifen-inducible fibroblast-specific scleraxis knockout (Scx-fKO) completely attenuated cardiac fibrosis, and significantly improved cardiac systolic function and ventricular remodelling, following TAC compared to Scx+/+ TAC mice, concomitant with attenuation of fibroblast activation. Scleraxis deletion, after the establishment of cardiac fibrosis, attenuated the further functional decline observed in Scx+/+ mice, with a reduction in cardiac myofibroblasts. Notably, scleraxis knockout reduced pressure overload-induced mortality from 33% to zero, without affecting the degree of cardiac hypertrophy. Scleraxis directly regulated transcription of the myofibroblast marker periostin, and cardiac fibroblasts lacking scleraxis failed to upregulate periostin synthesis and secretion in response to pro-fibrotic transforming growth factor ß. CONCLUSION: Scleraxis governs fibroblast activation in pressure overload-induced heart failure, and scleraxis knockout attenuated fibrosis and improved cardiac function and survival. These findings identify scleraxis as a viable target for the development of novel anti-fibrotic treatments.

Serum microRNA Levels as a Biomarker for Diagnosing Non-Alcoholic Fatty Liver Disease in Chinese Colorectal Polyp Patients.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases and its prevalence is increasing worldwide. It is reported that NAFLD is associated with colorectal polyps. Since identifying NAFLD in its early stages could prevent possible disease progression to cirrhosis and decrease the risk of HCC by early intervention, patients with colorectal polyp may thus be considered a target group for screening NAFLD. This study aimed to investigate the potential of serum microRNAs (miRNAs) in identifying NAFLD for colorectal polyp patients. Serum samples were collected from 141 colorectal polyp patients, of which 38 had NAFLD. The serum level of eight miRNAs was determined by quantitative PCR and delta Ct values of different miRNA pairs which were compared between NAFLD and control groups. A miRNA panel was formulated from candidate miRNA pairs by multiple linear regression model and ROC analysis was performed to evaluate its diagnostic potential for NAFLD. Compared to the control group, the NAFLD group showed significantly lower delta Ct values of miR-18a/miR-16 (6.141 vs. 7.374, p = 0.009), miR-25-3p/miR-16 (2.311 vs. 2.978, p = 0.003), miR-18a/miR-21-5p (4.367 vs. 5.081, p = 0.021) and miR-18a/miR-92a-3p (8.807 vs. 9.582, p = 0.020). A serum miRNA panel composed of these four miRNA pairs significantly identified NAFLD in colorectal polyp patients with an AUC value of 0.6584 (p = 0.004). The performance of the miRNA panel was further improved to an AUC value of 0.8337 (p < 0.0001) when polyp patients with other concurrent metabolic disorders were removed from the analysis. The serum miRNA panel is a potential diagnostic biomarker for screening NAFLD in colorectal polyp patients. This serum miRNA test could be performed for colorectal polyp patients for early diagnosis and for prevention of the disease from progressing into more advanced stages.

Effect of Surface Hydrophobicity on the Adsorption of a Pilus-Derived Adhesin-like Peptide.

Bacterial colonization of abiotic surfaces such as those of medical implants, membrane filters, and everyday household items is a process of tremendous importance for public health. Bacteria use adhesive cell surface structures called adhesins to establish contact with abiotic surfaces. Among them, protein filaments called type IV pili are particularly important and found in many Gram-negative pathogens such as Pseudomonas aeruginosa. Understanding the interaction of such adhesin proteins with different abiotic surfaces at the molecular level thus represents a fundamental prerequisite for impeding bacterial colonization and preventing the spread of infectious diseases. In this work, we investigate the interaction of a synthetic adhesin-like peptide, PAK128-144ox, derived from the type IV pilus of P. aeruginosa with hydrophilic and hydrophobic self-assembled monolayers (SAMs). Using a combination of molecular dynamics (MD) simulations, quartz crystal microbalance with dissipation monitoring (QCM-D), and spectroscopic investigations, we find that PAK128-144ox has a higher affinity for hydrophobic than for hydrophilic surfaces. Additionally, PAK128-144ox adsorption on the hydrophobic SAM is furthermore accompanied by a strong increase in α-helix content. Our results show a clear influence of surface hydrophobicity and further indicate that PAK128-144ox adsorption on the hydrophobic surface is enthalpically favored, while on the hydrophilic surface, entropic contributions are more significant. However, our spectroscopic investigations also suggest aggregation of the peptide under the employed experimental conditions, which is not considered in the MD simulations and should be addressed in more detail in future studies.

Elimination of endogenous high molecular weight FGF2 prevents pressure-overload-induced systolic dysfunction, linked to increased FGFR1 activity and NR1D1 expression.

Fibroblast growth factor 2 (FGF2), produced as high (Hi-) and low (Lo-) molecular weight isoforms, is implicated in cardiac response to injury. The role of endogenous FGF2 isoforms during chronic stress is not well defined. We investigated the effects of endogenous Hi-FGF2 in a mouse model of simulated pressure-overload stress achieved by transverse aortic constriction (TAC) surgery. Hi-FGF2 knockout mice, expressing only Lo-FGF2, FGF2(Lo), and wild-type mice, FGF2(WT), expressing both Hi-FGF2 and Lo-FGF2, were used. By echocardiography, a decline in systolic function was observed in FGF2(WT) but not FGF2(Lo) mice compared to corresponding sham-operated animals at 4-8 weeks post-TAC surgery. TAC surgery increased markers of myocardial stress/damage including B-type natriuretic peptide (BNP) and the pro-cell death protein BCL2/adenovirus E1B 19 kDa protein-interacting protein-3 (Bnip3) in FGF2(WT) but not FGF2(Lo) mice. In FGF2(Lo) mice, cardiac levels of activated FGF receptor 1 (FGFR1), and downstream signals, including phosphorylated mTOR and p70S6 kinase, were elevated post-TAC. Finally, NR1D1 (nuclear receptor subfamily 1 group D member 1), implicated in cardioprotection from pressure-overload stress, was downregulated or upregulated in the presence or absence, respectively, of Hi-FGF2 expression, post-TAC surgery. In wild-type cardiomyocyte cultures, endothelin-1 (added to simulate pressure-overload signals) caused NR1D1 downregulation and BNP upregulation, similar to the effect of TAC surgery on the FGF2(WT) mice. The NR1D1 agonist SR9009 prevented BNP upregulation, simulating post-TAC findings in FGF2(Lo) mice. We propose that elimination of Hi-FGF2 is cardioprotective during pressure-overload by increasing FGFR1-associated signaling and NR1D1 expression.

The Cardioprotective Role of Flaxseed in the Prevention of Doxorubicin- and Trastuzumab-Mediated Cardiotoxicity in C57BL/6 Mice.

BACKGROUND: Although the combination of doxorubicin (DOX) and trastuzumab (TRZ) reduces the progression and recurrence of breast cancer, these anticancer drugs are associated with significant cardiotoxic side effects. OBJECTIVE: We investigated whether prophylactic administration of flaxseed (FLX) and its bioactive components, α-linolenic acid (ALA) and secoisolariciresinol diglucoside (SDG), would be cardioprotective against DOX + TRZ-mediated cardiotoxicity in a chronic in vivo female murine model. METHODS: Wild-type C57BL/6 female mice (10-12 wk old) received daily prophylactic treatment with one of the following diets: 1) regular control (RC) semi-purified diet; 2) 10% FLX diet; 3) 4.4% ALA diet; or 4) 0.44% SDG diet for a total of 6 wks. Within each arm, mice received 3 weekly injections of 0.9% saline or a combination of DOX [8 mg/(kg.wk)] and TRZ [3 mg/(kg.wk)] starting at the end of week 3. The main outcome was to evaluate the effects of FLX, ALA, and SDG on cardiovascular remodeling and markers of apoptosis, inflammation, and mitochondrial dysfunction. Significance between measurements was determined using a 4 (diet) × 2 (chemotherapy) × 2 (time) mixed factorial design with repeated measures. RESULTS: In the RC + DOX + TRZ-treated mice at week 6 of the study, the left ventricular ejection fraction (LVEF) decreased by 50% compared with the baseline LVEF (P < 0.05). However, the prophylactic administration of the FLX, ALA, or SDG diet was partially cardioprotective, with mice in these treatment groups showing an ∼68% increase in LVEF compared with the RC + DOX + TRZ-treated group at week 6 (P < 0.05). Although markers of inflammation (nuclear transcription factor κB), apoptosis [poly (ADP-ribose) polymerase-1 and the ratio of BCL2-associated X protein to B-cell lymphoma-extra large], and mitochondrial dysfunction (BCL2-interacting protein 3) were significantly elevated by approximately 2-fold following treatment with RC + DOX + TRZ compared with treatment with RC + saline at week 6, prophylactic administration of FLX, ALA, or SDG partially downregulated these signaling pathways. CONCLUSION: In a chronic in vivo female C57BL/6 mouse model of DOX + TRZ-mediated cardiotoxicity, FLX, ALA, and SDG were partially cardioprotective.

Cardiac structure and function in youth with type 2 diabetes in the iCARE cohort study: Cross-sectional associations with prenatal exposure to diabetes and metabolomic profiles.

OBJECTIVE: This study aimed to determine the degree of left ventricular (LV) dysfunction and its determinants in adolescents with type 2 diabetes (T2D). We hypothesized that adolescents with T2D would display impaired LV diastolic function and that these cardiovascular complications would be exacerbated in youth exposed to maternal diabetes in utero. METHODS: Left ventricular structure and function, carotid artery intima media thickness and strain, and serum metabolomic profiles were compared between adolescents with T2D (n = 121) and controls (n = 34). Sub-group analyses examined the role of exposure to maternal diabetes as a determinant of LV or carotid artery structure and function among adolescents with T2D. RESULTS: Adolescents with T2D were 15.1 ± 2.5 years old, (65% female, 99% Indigenous), had lived with diabetes for 2.7 ± 2.2 years, had suboptimal glycemic control (HbA1c = 9.4 ± 2.6%) and 58% (n = 69) were exposed to diabetes in utero. Compared to controls, adolescents with T2D displayed lower LV diastolic filling (early diastole/atrial filling rate ratio [E/A] = 1.9 ± 0.6 vs 2.2 ± 0.6, P = 0.012), lower LV relaxation and carotid strain (0.12 ± 0.05 vs 0.17 ± 0.05, P = .03) and elevated levels of leucine, isoleucine and valine. Among adolescents with T2D, exposure to diabetes in utero was not associated with differences in LV diastolic filling, LV relaxation, carotid strain or branched chain amino acids. CONCLUSIONS: Adolescents with T2D display LV diastolic dysfunction, carotid artery stiffness, and elevated levels of select branch chain amino acids; differences were not associated with exposure to maternal diabetes in utero.

Scleraxis as a prognostic marker of myocardial fibrosis in hypertrophic cardiomyopathy (SPARC) study.

Interstitial fibrosis is a histopathological hallmark of hypertrophic cardiomyopathy (HCM). Although extracellular matrix (ECM) biomarkers, including matrix metalloproteinases, are overexpressed in HCM patients, they do not correlate with sudden cardiac death (SCD) risk. The objective of this study was to determine whether scleraxis, a transcription factor that regulates collagen gene expression, is detectable in HCM patients and correlates with disease burden. Between 2017 and 2018, a total of 46 HCM patients were enrolled (58 ± 14 years (31 males, 15 females)) with a mean 5 year SCD risk of 2.3% ± 1.3%. Cardiac MRI confirmed HCM in all patients with a mean interventricular septal thickness of 20 ± 2 mm. Late gadolinium enhancement (LGE) was present in 32 (70%) study participants occupying 18% ± 7% of the left ventricular (LV) myocardium. Serum scleraxis levels were significantly higher in the HCM patients by approximately twofold as compared to controls (0.76 ± 0.06 versus 0.32 ± 0.02 ng/mL, p < 0.05). No correlation was demonstrated between serum scleraxis levels and markers of disease severity in HCM patients, including maximum LV wall thickness, %LGE, and SCD risk factors. Serum scleraxis is elevated in the HCM population. Future studies are warranted to evaluate the prognostic value of scleraxis in identifying high-risk HCM patients who require aggressive management for prevention of SCD.

Role of renin-angiotensin system antagonists in the prevention of bevacizumab- and sunitinib-mediated cardiac dysfunction.

Although anticancer systemic therapy agents clearly lead to improved survival in patients with cancer, these can come at the cost of serious complications including cardiotoxicity. Two types of targeted systemic therapies currently in use for colorectal cancer (CRC) and renal cell cancer (RCC), respectively, include the vascular endothelial growth factor inhibitor bevacizumab (BVZ) and the tyrosine kinase inhibitor sunitinib (SNT). Despite the beneficial effects of BVZ and SNT in improving clinical outcomes in the settings of CRC and RCC, there is an increased risk of cardiac dysfunction. The aim of the present study was to determine whether prophylactic administration of renin-angiotensin system (RAS) inhibitors would attenuate the cardiotoxic side effects of BVZ or SNT in a chronic in vivo murine model. A total of 194 wild-type C57Bl/6 male mice received: 1) 0.9% saline, 2) BVZ (10 mg·kg-1·wk-1), or 3) SNT (40 mg·kg-1·day-1) for 4 wk. Within each arm, mice received daily prophylactic treatment with hydralazine (0.05 mg/ml), aliskiren (50 mg/kg), perindopril (4 mg/kg), or valsartan (2 mg/kg). Although hydralazine effectively lowered blood pressure in BVZ- or SNT-treated mice, it did not prevent left ventricular systolic dysfunction. Prophylactic administration of aliskiren, perindopril, or valsartan prevented adverse cardiovascular remodeling in mice treated with either BVZ or SNT. The addition of RAS antagonists also downregulated expression of phosphorylated p38 and Bcl-2-like 19-kDa interacting protein 3 in SNT-treated mice. In our chronic in vivo murine model, RAS antagonists partially attenuated the development of BVZ- or SNT-mediated cardiac dysfunction. Future clinical studies are warranted to investigate the cardioprotective effects of prophylactic treatment with RAS inhibitors in the settings of CRC and RCC. NEW & NOTEWORTHY In the evolving field of cardio-oncology, bevacizumab and sunitinib improve clinical outcomes in the settings of metastatic colorectal cancer and renal cell cancer, respectively. These anticancer drugs, however, are associated with an increased risk of cardiotoxicity. The prophylactic administration of renin-angiotensin system antagonists is partially cardioprotective against bevacizumab- and sunitinib-mediated cardiac dysfunction.

Measuring the Impact of PEGylation on a Protein-Polysaccharide Interaction.

PEGylation is the most widely used half-life extension strategy for protein therapeutics. While it imparts a range of attractive attributes PEGylation can impede protein binding and reduce efficacy. A model system to probe the effects of PEGylation on protein binding has practical applications. Here, we present a system based on complex formation between a hexavalent lectin (RSL) and the globular polysaccharide Ficoll PM70 (a type of glycocluster). Mutants of the lectin were used to generate conjugates with 3, 6, or 12 PEG (1 kDa) chains. Using NMR spectroscopy we monitored how the degree of PEGylation impacted the lectin-Ficoll interaction. The binding propensity was observed to decrease with increasing polymer density. Apparently, the extended PEG chains sterically impede the lectin-Ficoll binding. This deduction was supported by molecular dynamics simulations of the protein-polymer conjugates. The implications for protein-surface interactions are discussed.

Atomistic Study of Zwitterionic Peptoid Antifouling Brushes.

Using molecular dynamics (MD) simulations, we study the molecular behavior and hydration properties of a set of zwitterionic "peptoid" brushes, grafted on a rutile surface, that has been previously reported to exhibit excellent resistance against protein adsorption and cell attachment. Peptoids are novel poly( N-substituted glycine) peptide mimics with the side chains attached to amide nitrogens. They constitute a unique model polymer system because hundreds of side chains have been demonstrated, and the exact chain length and sequence order of the residues/monomers may be specified in experiments. In this report, we vary the brush grafting density as well as the side chain/polymer molecular volume. We include in our study polysarcosine as an uncharged comparison with a small polymer chain cross-section. Sarcosine is the simplest peptoid residue with only a nominally hydrophobic methyl group as side chain, but is also reported to exhibit high antifouling performance. Overall, we show in detail how molecular volume and hydration effects are intertwined in a zwitterionic polymer brush. For example, the zwitterionic design significantly promotes extended chain conformations and could actually lower the overall electrostatic potential. Some properties promoted by the balanced charges, such as chain flexibility and hydration, increase more prominently at "low" to "intermediate" chain densities. These and other observations should provide insight on the molecular behavior of peptoids and inform the design of zwitterionic antifouling polymer brushes.

Change in treatment paradigm in people who previously injected drugs with chronic hepatitis C in the era of direct-acting antiviral therapy.

BACKGROUND: Chronic hepatitis C virus (HCV) infection is highly prevalent among people who inject drugs but is often undiagnosed. The treatment paradigm for HCV patients has been changing since the availability of direct-acting antiviral (DAA) treatment. We aimed to evaluate the change in treatment paradigm of people who previously injected drugs (ex-PWID) in Hong Kong before and after the availability of DAA. METHOD: Consecutive ex-PWID referred from various nongovernmental organizations attended education talks at rehabilitation centers and received point-of-care rapid test for HCV antibody (anti-HCV) at the same session. Subjects tested positive for anti-HCV were invited to undergo further assessment. Afterwards, the patients were referred to the regional hospitals for follow-up and/or treatment. RESULTS: Three hundred sixty-five ex-PWID received HCV rapid test; 268 (73.4%) were found to be anti-HCV positive. Among these 268 HCV-positive ex-PWID, 234 (87.3%) attended the assessment session (mean age 52 years, 90.2% male, 45.5% genotype 1b, 41.1% genotype 6a, and median liver stiffness 5.9 kPa); 187 (69.8%) attended follow-up visits at regional hospitals. Seventy-one patients received antiviral treatment for HCV; 69 first received peginterferon and ribavirin (PegIFN/RBV), whereas 10 patients (eight PegIFN/RBV-treated patients) received DAA treatment. Fifty-two patients achieved sustained virologic response at 12 or 24 weeks. Treatment uptake rates of PegIFN/RBV and DAA treatment in the pre-DAA versus post-DAA era were 22.3% versus 48.5% and 0% versus 15.6%, respectively. CONCLUSIONS: Targeted screening in ex-PWID is effective in identifying patients with HCV infection in the community. To improve treatment uptake, further improvements in the referral system and treatment regimens are needed.

Adaptation of the length scale and amplitude of the Bicoid gradient profile to achieve robust patterning in abnormally large Drosophila melanogaster embryos.

The formation of patterns that are proportional to the size of the embryo is an intriguing but poorly understood feature of development. Molecular mechanisms controlling such proportionality, or scaling, can be probed through quantitative interrogations of the properties of morphogen gradients that instruct patterning. Recent studies of the Drosophila morphogen gradient Bicoid (Bcd), which is required for anterior-posterior (AP) patterning in the early embryo, have uncovered two distinct ways of scaling. Whereas between-species scaling is achieved by adjusting the exponential shape characteristic of the Bcd gradient profile, namely, its length scale or length constant (λ), within-species scaling is achieved through adjusting the profile's amplitude, namely, the Bcd concentration at the anterior (B0). Here, we report a case in which Drosophila melanogaster embryos exhibit Bcd gradient properties uncharacteristic of their size. The embryos under investigation were from a pair of inbred lines that had been artificially selected for egg size extremes. We show that B0 in the large embryos is uncharacteristically low but λ is abnormally extended. Although the large embryos have more total bcd mRNA than their smaller counterparts, as expected, its distribution is unusually broad. We show that the large and small embryos develop gene expression patterns exhibiting boundaries that are proportional to their respective lengths. Our results suggest that the large-egg inbred line has acquired compensating properties that counteract the extreme length of the embryos to maintain Bcd gradient properties necessary for robust patterning. Our study documents, for the first time to our knowledge, a case of within-species Bcd scaling achieved through adjusting the gradient profile's exponential shape characteristic, illustrating at a molecular level how a developmental system can follow distinct operational paths towards the goal of robust and scaled patterning.

Macroscopic chiral symmetry breaking in monolayers of achiral nonconvex platelets.

The fabrication of chiral structures using achiral building blocks is a fundamental problem that remains a challenge in materials science. In this work we present a molecular dynamics simulation study of nonconvex polygonal platelets, interacting via soft-repulsive interactions, that are confined in two-dimensional space. These particle models are designed to promote, even at moderate densities, a natural offset displacement between the edges of neighbouring particles. In particular we demonstrate that nonconvex platelets exhibit macroscopic chiral symmetry breaking when the symmetry of the particles equals (or is multiple of) the number of nearest neighbours in the condensed crystalline phase, corresponding to the situation of platelets with 4-, 6-, and 12-fold symmetries.

Adsorption of the natural protein surfactant Rsn-2 onto liquid interfaces.

To stabilize foams, droplets and films at liquid interfaces a range of protein biosurfactants have evolved in nature. Compared to synthetic surfactants, these combine surface activity with biocompatibility and low solution aggregation. One recently studied example is Rsn-2, a component of the foam nest of the frog Engystomops pustulosus, which has been predicted to undergo a clamshell-like opening transition at the air-water interface. Using atomistic molecular dynamics simulations and surface tension measurements we study the adsorption of Rsn-2 onto air-water and cyclohexane-water interfaces. The protein adsorbs readily at both interfaces, with adsorption mediated by the hydrophobic N-terminus. At the cyclohexane-water interface the clamshell opens, due to the favourable interaction between hydrophobic residues and cyclohexane molecules and the penetration of cyclohexane molecules into the protein core. Simulations of deletion mutants showed that removal of the N-terminus inhibits interfacial adsorption, which is consistent with the surface tension measurements. Deletion of the hydrophilic C-terminus also affects adsorption, suggesting that this plays a role in orienting the protein at the interface. The characterisation of the interfacial behaviour gives insight into the factors that control the interfacial adsorption of proteins, which may inform new applications of this and similar proteins in areas including drug delivery and food technology and may also be used in the design of synthetic molecules showing similar changes in conformation at interfaces.

Adsorption and conformations of lysozyme and α-lactalbumin at a water-octane interface.

As proteins contain both hydrophobic and hydrophilic amino acids, they will readily adsorb onto interfaces between water and hydrophobic fluids such as oil. This adsorption normally causes changes in the protein structure, which can result in loss of protein function and irreversible adsorption, leading to the formation of protein interfacial films. While this can be advantageous in some applications (e.g., food technology), in most cases it limits our ability to exploit protein functionality at interfaces. To understand and control protein interfacial adsorption and function, it is necessary to understand the microscopic conformation of proteins at liquid interfaces. In this paper, molecular dynamics simulations are used to investigate the adsorption and conformation of two similar proteins, lysozyme and α-lactalbumin, at a water-octane interface. While they both adsorb onto the interface, α-lactalbumin does so in a specific orientation, mediated by two amphipathic helices, while lysozyme adsorbs in a non-specific manner. Using replica exchange simulations, both proteins are found to possess a number of distinct interfacial conformations, with compact states similar to the solution conformation being most common for both proteins. Decomposing the different contributions to the protein energy at oil-water interfaces suggests that conformational change for α-lactalbumin, unlike lysozyme, is driven by favourable protein-oil interactions. Revealing these differences between the factors that govern the conformational change at interfaces in otherwise similar proteins can give insight into the control of protein interfacial adsorption, aggregation, and function.

Evaluating Efficacy and Safety of Combination Medication of Atorvastatin and a Herbal Formula Containing Salvia miltiorrhiza and Pueraria lobata on Hyperlipidemia.

Despite being a potent hypolipidemic drug, atorvastatin (AS) possesses certain adverse effects. Using AS and an herbal formula (Danshen and Gegen, DG) in combination may achieve potentiated hypolipidemic effects and also reduce its adverse effects. Hence, this study aimed to investigate the efficacy and safety of an AS and DG combination on high-fat diet-induced hyperlipidemia. Treatment outcomes were assessed by measuring parameters including body weight, adipose tissue, liver, total cholesterol, triglyceride, and low-density and high-density lipoprotein cholesterol. Measurements of adverse effects were achieved by determining aspartate aminotransferase (AST), alanine transaminase (ALT), and creatine kinase (CK). Danshen and Gegen, as well as AS alone, reduced body weight, adipose tissue, liver weight, liver fat vacuoles, total liver lipids, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in high-fat diet-fed mice but increased AST, ALT, and CK. A combination of AS and DG was able to enhance reduced effects on the aforementioned parameters in relation to hyperlipidemia over AS or DG alone. It also reduced the elevation of AST, ALT, and CK induced than by AS or DG alone. Results demonstrated that an AS and DG combination resulted in stronger hypolipidemic effects than with AS or DG alone. Additionally, DG might attenuate adverse effects of AS on the liver and skeletal muscle. Copyright © 2017 John Wiley & Sons, Ltd.

Conformations of Myoglobin-Derived Peptides at the Air-Water Interface.

The conformational change exhibited by proteins at liquid interfaces, such as the air-water and oil-water interfaces, has long been of interest both for understanding protein structure outside of native environments and for applications in areas including food technology and pharmaceuticals. Using molecular simulation, this article studies the conformations of two peptides derived from myoglobin, for which the emulsification behavior has been studied. Both peptides were found to readily adsorb onto the air-water interface, with one of these (experimentally, the more effective stabilizer) adopting a flat, extended conformation and the other peptide remaining close to its solution conformation.

The modulation of BDNF expression and signalling dissects the antidepressant from the reinforcing properties of ketamine: Effects of single infusion vs. chronic self-administration in rats.

Ketamine is a drug of abuse with a unique profile, which besides its inherent mechanism of action as a non-competitive antagonist of the NMDA glutamate receptor, displays both antidepressant and reinforcing properties. The major aim of our study was to find a molecular signature of ketamine that may help in discriminating between its reinforcing and antidepressant effects. To this end, we focused our attention on BDNF, a neurotrophin that has been shown to play a role in both antidepressant and reinforcing properties of several drugs. Rats were exposed to self-administer intravenous (IV) ketamine (S/A) for 43 days or to receive a single IV ketamine 0.5mg/kg, or vehicle infusion. Although the dose we employed is lower than that reported by the literature, it however yields Cmax values that correspond to those achieved in humans after antidepressant treatment. Our results show that while the single infusion of ketamine increased the neurotrophin expression in the hippocampus while reducing it in the ventral striatum, a feature shared with other antidepressants, the repeated self-administration reduced mBDNF expression and its downstream signalling in both ventral striatum and hippocampus. Further, we here show that phosphorylation of Akt is oppositely regulated by ketamine, pointing to this pathway as central to the different actions of the drug. Taken together, we here point to BDNF and its downstream signalling pathway as a finely tuned mechanism whose modulation might subserve the different features of ketamine.

Phase behaviour of self-assembled monolayers controlled by tuning physisorbed and chemisorbed states: A lattice-model view.

The self-assembly of molecules on surfaces into 2D structures is important for the bottom-up fabrication of functional nanomaterials, and the self-assembled structure depends on the interplay between molecule-molecule interactions and molecule-surface interactions. Halogenated benzene derivatives on platinum have been shown to have two distinct adsorption states: a physisorbed state and a chemisorbed state, and the interplay between the two can be expected to have a profound effect on the self-assembly and phase behaviour of these systems. We developed a lattice model that explicitly includes both adsorption states, with representative interactions parameterised using density functional theory calculations. This model was used in Monte Carlo simulations to investigate pattern formation of hexahalogenated benzene molecules on the platinum surface. Molecules that prefer the physisorbed state were found to self-assemble with ease, depending on the interactions between physisorbed molecules. In contrast, molecules that preferentially chemisorb tend to get arrested in disordered phases. However, changing the interactions between chemisorbed and physisorbed molecules affects the phase behaviour. We propose functionalising molecules in order to tune their adsorption states, as an innovative way to control monolayer structure, leading to a promising avenue for directed assembly of novel 2D structures.