Skin barrier lipid enzyme activity in Netherton patients is associated with protease activity and ceramide abnormalities

Individuals with Netherton syndrome (NTS) have increased serine protease activity, which strongly impacts the barrier function of the skin epidermis and leads to skin inflammation. Here, we investigated how serine protease activity in NTS correlates with changes in the stratum corneum (SC) ceramides, which are crucial components of the skin barrier. We examined two key enzymes involved in epidermal ceramide biosynthesis, β-glucocerebrosidase (GBA) and acid-sphingomyelinase (ASM). We compared in situ expression levels and activities of GBA and ASM between NTS patients and controls and correlated the expression and activities with i) SC ceramide profiles, ii) in situ serine protease activity, and iii) clinical presentation of patients. Using activity-based probe labeling, we visualized and localized active epidermal GBA, and a newly developed in situ zymography method enabled us to visualize and localize active ASM. Reduction in active GBA in NTS patients coincided with increased ASM activity, particularly in areas with increased serine protease activity. NTS patients with scaly erythroderma exhibited more pronounced anomalies in GBA and ASM activities than patients with ichthyosis linearis circumflexa. They also displayed a stronger increase in SC ceramides processed via ASM. We conclude that changes in the localization of active GBA and ASM correlate with i) altered SC ceramide composition in NTS patients, ii) local serine protease activity, and iii) the clinical manifestation of NTS.

Alteration of renal Na,K-ATPase in rats following the mediastinal γ-irradiation

Na,K-ATPase represents the key enzyme that maintains the homeostasis of sodium and potassium ions in the cells. It was documented that in directly irradiated organs the activity of this enzyme is decreased. The aim of present study was to clarify the remote effect of irradiation in mediastinal area on the activity of the Na,K-ATPase in kidneys in rats. Ionizing radiation in single dose 25 Gy resulted in consequent decrease of the body weight gain as well as the size of kidneys in Wistar rats. In addition, radiation induced alterations in the oxidative status of blood plasma. Irradiation also decreased the activity of renal Na,K-ATPase. Measurements of enzyme kinetics that were dependent on the concentration of energy substrate ATP or cofactor Na+ indicated that the lowered enzyme activity is probably a consequence of decreased number of active molecules of the enzyme, as suggested by lowered Vmax values. Immunoblot analysis confirmed the lowered expression of the catalytic alpha subunit together with decreased content of the glycosylated form of beta subunit in the renal tissue of irradiated rats. The ability of the enzyme to bind the substrate ATP, as well as Na+ was not affected, as shown by unaltered values of Km and KNa . Irradiation of the body in the mediastinal area despite protection of kidneys by lead plates during application of X-ray was followed by significant decline of activity of the renal Na,K-ATPase, what may result in deteriorated homeostasis in the organism.

Therapeutic Delivery of Butyrylcholinesterase by Brain-Wide Viral Gene Transfer to Mice

Recent research shows that butyrylcholinesterase (BChE) is not simply a liver enzyme that detoxifies bioactive esters in food and medications. In fact, in pursuing other goals, we recently found that it has an equally important role in regulating the peptide hormone ghrelin and its impact on hunger, obesity, and emotions. Here, we present and examine means of manipulating brain BChE levels by viral gene transfer, either regionally or globally, to modulate ghrelin signaling for long-term therapeutic purposes and to set the stage for exploring the neurophysiological impact of such an intervention.

Folding Assessment of Incorporation of Noncanonical Amino Acids Facilitates Expansion of Functional-Group Diversity for Enzyme Engineering

Protein design is limited by the diversity of functional groups provided by the canonical protein „building blocks“. Incorporating noncanonical amino acids (ncAAs) into enzymes enables a dramatic expansion of their catalytic features. For this, quick identification of fully translated and correctly folded variants is decisive. Herein, we report the engineering of the enantioselectivity of an esterase utilizing several ncAAs. Key for the identification of active and soluble protein variants was the use of the split‐GFP method, which is crucial as it allows simple determination of the expression levels of enzyme variants with ncAA incorporations by fluorescence. Several identified variants led to improved enantioselectivity or even inverted enantiopreference in the kinetic resolution of ethyl 3‐phenylbutyrate.

Expression and Retention of Thymidine Phosphorylase in Cultured Reticulocytes as a Novel Treatment for MNGIE

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal metabolic disorder caused by thymidine phosphorylase (TP) deficiency. Successful therapeutic interventions for this disease rely on a means for efficient and long-lasting circulation of the TP enzyme. In this study we exploit lentiviral transduction of hematopoietic stem cells and an erythroid cell line (BEL-A) to generate reticulocytes that contain active TP. Significant loss of overexpressed TP during erythroid differentiation can be reduced by addition of the ubiquitination inhibitor MG132. However, the ubiquitination sites are located in the substrate binding site in human TP, and their removal abolished enzyme activity. Examination of the TP structure and mechanism suggested that these sites are only exposed in the absence of substrate. We show that supplementation of culture media with thymidine during differentiation reduces enzyme degradation, doubling the amount of TP retained in reticulocytes. This study provides proof of principle that therapeutic reticulocytes expressing TP can be generated in vitro and that ubiquitin-mediated degradation can be subverted through masking ubiquitination sites to ensure retention of human TP in reticulocytes following erythroid differentiation.

Characterization of a Novel Superoxide Dismutase from a Deep-sea Sea Cucumber (Psychoropotes verruciaudatus)

At present, deep-sea enzymes are a research hotspot. In this study, a novel copper-zinc superoxide dismutase (CuZnSOD) was successfully cloned and characterized from a new species of sea cucumber Psychropotes verruciaudatus (PVCuZnSOD). The relative molecular weight of the PVCuZnSOD monomer is 15 kDa. The optimum temperature of PVCuZnSOD is 20 °C, and it maintains high activity in the range of 0-60 °C. It also has high thermal stability when incubated at 37 °C. PVCuZnSOD has a maximum activity of more than 50% in the pH range of 4-11 and a high activity at pH 11. In addition, PVCuZnSOD has strong tolerance to Ni²⁺, Mg²⁺, Ba²⁺, and Ca²⁺, and it can withstand chemical reagents, such as Tween20, TritonX-100, ethanol, glycerol, isopropanol, DMSO, urea, and GuHCl. PVCuZnSOD also shows great stability to gastrointestinal fluid compared with bovine SOD. These characteristics show that PVCuZnSOD has great application potential in medicine, food, and other products.

Pipeline for Analyzing Activity of Metabolic Pathways in Planktonic Communities Using Metatranscriptomic Data

In this article, we present our novel pipeline for analysis of metabolic activity using a microbial community's metatranscriptome sequence data set for validation. Our method is based on expectation-maximization (EM) algorithm and provides enzyme expression and pathway activity levels. Further expanding our analysis, we consider individual enzymatic activity and compute enzyme participation coefficients to approximate the metabolic pathway activity more accurately. We apply our EM pathways pipeline to a metatranscriptomic data set of a plankton community from surface waters of the Northern Gulf of Mexico. The data set consists of RNA-seq data and respective environmental parameters, which were sampled at two depths, six times a day over multiple 24-hour cycles. Furthermore, we discuss microbial dependence on day-night cycle within our findings based on a three-way correlation of the enzyme expression during antipodal times-midnight and noon. We show that the enzyme participation levels strongly affect the metabolic activity estimates: that is, marginal and multiple linear regression of enzymatic and metabolic pathway activity correlated significantly with the recorded environmental parameters. Our analysis statistically validates that EM-based methods produce meaningful results, as our method confirms statistically significant dependence of metabolic pathway activity on the environmental parameters, such as salinity, temperature, brightness, and a few others.

A Simple and Effective Strategy for the Development of Robust Promoter-Centric Gene Expression Tools

Promoter-centric genetic tools play a crucial role in controlling gene expression for various applications, such as strain engineering and synthetic biology studies. Hence, a critical need persists for the development of robust gene expression tools. Streptomyces are well-known prolific producers of natural products and exceptional surrogate hosts for the production of high-value chemical compounds and enzymes. In this study, we reported a straightforward and effective strategy for the creation of potent gene expression tools. This was primarily achieved by introducing an additional -35-like motif upstream of the original -35 region of the promoter, coupled with the integration of a palindromic cis-element into the 5'-UTR region. This approach has generated a collection of robust constitutive and inducible gene expression tools tailored for Streptomyces. Of particular note, the fully activated oxytetracycline-inducible gene expression system containing an engineered kasOp* promoter (OK) exhibited nearly an order of magnitude greater activity compared to the well-established high-strength promoter kasOp* under the tested conditions, establishing itself as a powerful gene expression system for Streptomyces. This strategy is expected to be applicable in modifying various other promoters to acquire robust gene expression tools, as evidenced by the enhancement observed in the other two promoters, PL and P21 in this study. Moreover, the effectiveness of these tools has been demonstrated through the augmented production of transglutaminase and daptomycin. The gene expression tools established in this study, alongside those anticipated in forthcoming research, are positioned to markedly advance pathway engineering and synthetic biology investigations in Streptomyces and other microbial strains.

Evaluation of diflubenzuron-verapamil combination strategy for eco-safe management of Aedes aegypti

Introduction

Aedes aegypti, the vector of multiple arboviral diseases, is a prime health concern worldwide. The surge in Aedes-borne diseases emphasizes the urgent need for efficient vector control measures. Synthetic pesticides used traditionally, however, present environmental concerns and issues like resistance development, causing the use of higher chemical doses. Hence, alternate interventions like the use of insect growth regulators (diflubenzuron; DFB) show promise because of their unique mechanism of action and environmental safety. Nevertheless, mosquitoes have the potential to develop resistance to any chemical. Thus, the present study investigates the use of DFB in combination with verapamil (DFB-V; 1:10) as a possible mosquito intervention measure.

Methods

The effects of both DFB and DFB-V were assessed on the larval development, adult emergence and expression of detoxification enzymes, non-specific esterases, glutathione S-transferase (GST), acetylcholinesterase (AChE), and monooxygenases in laboratory-reared (AND-Ae. aegypti) and wild-caught (GVD-Ae. aegypti) strains of Ae. aegypti. The effects on the survival of non-target organisms were also investigated.

Results

The investigations showed that DFB-V treatment of the Ae. aegypti fourth instars caused a 1.16-1.37 fold higher adult emergence suppression than DFB alone, reducing the IE50 values. The DFB treatment increased β-esterases, AChE, and monooxygenases but reduced the GST and α-esterase levels. The effects enhanced with the use of DFB-V, causing a significant decrease in α-esterase (7.7-fold) and an increase in monooxygenases (7.8-fold) (p < 0.05) in AND-Ae. aegypti compared to the wild-caught strain. The variation in enzyme levels in the two strains may be due to the stress caused by insecticides of different chemical natures used in the fields. No negative effects were observed on the non-target organisms-Gambusia affinis, Mesocyclops thermocyclopoides, and Paramecium tetraurelia.

Conclusion

The studies showed the growth regulatory efficacy of DFB and probable role of GST and α-esterases in increasing the effects of DFB when synergized with verapamil. Further, the DFB-V combination did not result in any significant negative effects on the non-target organisms ascertaining its safe use. This is the first report unraveling the effects of the DFB-verapamil combination on the defense mechanism of Ae. aegypti. Further studies may assist in developing focused and eco-safe plans for managing Ae. aegypti populations effectively.

Expression and function of the urea cycle in widely-used hepatic cellular models

The group of rare metabolic defects termed urea cycle disorders (UCDs) occur within the ammonia elimination pathway and lead to significant neurocognitive sequelae for patients surviving decompensation episodes. Besides orthotopic liver transplantation, curative options are lacking for UCDs, with dietary management being the gold clinical standard. Novel therapeutic approaches are essential for UCDs; however, such effort presupposes preclinical testing in cellular models that effectively capture disease manifestation. Several cellular and animal models exist and aim to recapitulate the broad phenotypic spectrum of UCDs; however, the majority of those lack extensive molecular and biochemical characterization. The development of cellular models is emerging since animal models are extremely time and cost consuming, and subject to ethical considerations, including the 3R principle that endorses animal welfare over unchecked preclinical testing. The aim of this study was to compare the extent of expression and functionality of the urea cycle in two commercial hepatoma-derived cell lines, induced pluripotent stem cell hepatocytes (iPSC-Heps), primary human hepatocytes (PHHs) and human liver cell preparations. Using immunoblotting, immunocytochemistry, and stable isotope tracing of the urea cycle metabolites, we identified that the hepatoma-derived, 2-week differentiated HepaRG cells are urea cycle proficient and behave as cellular alternatives to PHHs. Furthermore, HepaRG cells were superior to iPSC-Heps, which are known to exhibit batch-to-batch variabilities in terms of hepatic maturity and enzyme expression. Finally, HepG2 cells lack the urea cycle enzymes ornithine transcarbamylase and arginase 1, the transporter ORNT1, which limits their suitability as model for the study of UCDs.

Estimating Enzyme Expression and Metabolic Pathway Activity in Borreliella-Infected and Uninfected Mice

Evaluating changes in metabolic pathway activity is essential for studying disease mechanisms and developing new treatments, with significant benefits extending to human health. Here, we propose EMPathways2, a maximum likelihood pipeline that is based on the expectation-maximization algorithm, which is capable of evaluating enzyme expression and metabolic pathway activity level. We first estimate enzyme expression from RNA-seq data that is used for simultaneous estimation of pathway activity levels using enzyme participation levels in each pathway. We implement the novel pipeline to RNA-seq data from several groups of mice, which provides a deeper look at the biochemical changes occurring as a result of bacterial infection, disease, and immune response. Our results show that estimated enzyme expression, pathway activity levels, and enzyme participation levels in each pathway are robust and stable across all samples. Estimated activity levels of a significant number of metabolic pathways strongly correlate with the infected and uninfected status of the respective rodent types.