Exploiting and Engineering Neuroglobin for Catalyzing Carbene N-H Insertions and the Formation of Quinoxalinones.

It is desired to design and construct more efficient enzymes with better performance to catalyze carbene N-H insertions for the synthesis of bioactive molecules. To this end, we exploited and designed a series of human neuroglobin (Ngb) mutants. As shown in this study, a double mutant, A15C/H64G Ngb, with an additional disulfide bond and a modified heme active site, exhibited yields up to >99% and total turnover numbers up to 33000 in catalyzing the carbene N-H insertions for aromatic amine derivatives, including those with a large size such as 1-aminopyrene.

Myoglobin mutant with enhanced nitrite reductase activity regulates intracellular oxidative stress in human breast cancer cells.

Heme proteins play vital roles in regulating the reactive oxygen/nitrogen species (ROS/RNS) levels in cells. In this study, we overexpressed human wild-type (WT) myoglobin (Mb) and its double mutant, F43H/H64A Mb with enhanced nitrite reductase (NIR) activity, in the typical representative triple-negative breast cancer cell, MDA-MB-231 cells. The results showed that the overexpression of F43H/H64A Mb increased the level of nitric oxide (NO) and the degree of oxidative stress, and then activated Akt/MAPK mediated apoptotic cascade, whereas WT Mb showed the opposite effect.

LINC01234 Accelerates the Progression of Breast Cancer via the miR-525-5p/Cold Shock Domain-Containing E1 Axis.

Backgrounds: Long noncoding RNAs (lncRNAs) are strongly associated with the development of breast cancer (BC). As yet, the function of LINC01234 in BC remains unknown.

Methods: Using biological information, the potential lncRNA, miRNA, and target gene were predicted.

Regulating Effect of Cytochrome Overexpression on Human Breast Cancer Cells.

Imbalance in the cellular redox system is thought to be associated with the induction and progression of breast cancers, and heme proteins may regulate the redox balance. Cytochrome (Cyt ) is a small mitochondrial heme protein. Its function and regulating mechanism in breast cancer remain unknown.

Engineering globins for efficient biodegradation of malachite green: two case studies of myoglobin and neuroglobin.

Malachite green (MG)-contaminated wastewater resulting from industrialization causes a global problem because of its toxicity and widespread usage. Compared with traditional physical and chemical approaches, biodegradation provides a new route for the degradation of MG. As promising candidates for native enzymes, artificial enzymes have received tremendous attention for potential applications due to unlimited possibilities based on precise design.

Efficient biodegradation of malachite green by an artificial enzyme designed in myoglobin.

Synthetic dyes such as malachite green (MG) have a wide range of applications. Meanwhile, they bring great challenges for environmental security and cause potential damages to human health. Compared with traditional approaches, enzymatic catalysis is an emerging technique for wastewater treatment.

Wnt signaling in triple-negative breast cancers: Its roles in molecular subtyping and cancer cell stemness and its crosstalk with non-coding RNAs.

Triple-negative breast cancers (TNBCs) are now acknowledged as a collection of diseases encompassing distinct histological plasticity, multi-tier molecular heterogeneity, as well as different outcomes. Despite decades of efforts, the molecular subtyping strategy has been theoretical, and target therapies based on molecular alternations barely improve survival rates of TNBC patients, and thus traditional chemotherapy remains the standard of care in clinic. The Wnt signaling is an evolutionarily conserved signaling pathway, playing critical roles in embryogenesis and neoplastic disease.

Naturally Occurring I81N Mutation in Human Cytochrome Regulates Both Inherent Peroxidase Activity and Interactions with Neuroglobin.

Human cytochrome (Cyt ) is a crucial heme protein and plays an indispensable role in energy conversion and intrinsic apoptosis pathways. The sequence and structure of Cyt were evolutionarily conserved and only a few naturally occurring mutants were detected in humans. Among those variable sites, position 81 was proposed to act as a peroxidase switch in the initiation stages of apoptosis.

Design and Engineering of an Efficient Peroxidase Using Myoglobin for Dye Decolorization and Lignin Bioconversion.

The treatment of environmental pollutants such as synthetic dyes and lignin has received much attention, especially for biotechnological treatments using both native and artificial metalloenzymes. In this study, we designed and engineered an efficient peroxidase using the O carrier myoglobin (Mb) as a protein scaffold by four mutations (F43Y/T67R/P88W/F138W), which combines the key structural features of natural peroxidases such as the presence of a conserved His-Arg pair and Tyr/Trp residues close to the heme active center. Kinetic studies revealed that the quadruple mutant exhibits considerably enhanced peroxidase activity, with the catalytic efficiency (/) comparable to that of the most efficient natural enzyme, horseradish peroxidase (HRP).

The X-ray crystal structure of human A15C neuroglobin reveals both native/de novo disulfide bonds and unexpected ligand-binding sites.

Human neuroglobin (Ngb) contains a heme group and three Cys residues (Cys46, Cys55, and Cys120) in the polypeptide chain. By introducing an additional Cys at position 15, the X-ray structure of A15C Ngb mutant was solved at a high resolution of 1.35 Å, which reveals the formation of both the native (C46C55) and the engineered (C15C120) disulfide bonds, likely playing a functional and structural role, respectively, according to the geometry analysis.

Exosomes in triple negative breast cancer: From bench to bedside.

Exosomes are lipid bilayer extracellular vesicles with a size of 30-150 nm, which can be released by various types of cells including breast cancer cells. Exosomes are enriched with multiple nucleic acids, lipids, proteins and play critical biological roles by binding to recipient cells and transmitting various biological cargos. Studies have reported that tumor-derived exosomes are involved in cancer initiation and progression, such as promoting cancer invasion and metastasis, accelerating angiogenesis, contributing to epithelial-mesenchymal transition, and enhancing drug resistance in tumors.

Phenoxazinone Synthase-like Activity of Rationally Designed Heme Enzymes Based on Myoglobin.

The design of functional metalloenzymes is attractive for the biosynthesis of biologically important compounds, such as phenoxazinones and phenazines catalyzed by native phenoxazinone synthase (PHS). To design functional heme enzymes, we used myoglobin (Mb) as a model protein and introduced an artificial CXXC motif into the heme distal pocket by F46C and L49C mutations, which forms a de novo disulfide bond, as confirmed by the X-ray crystal structure. We further introduced a catalytic Tyr43 into the heme distal pocket and found that the F43Y/F46C/L49C Mb triple mutant and the previously designed F43Y/F46S Mb exhibit PHS-like activity (80-98% yields in 5-15 min), with the catalytic efficiency exceeding those of natural metalloenzymes, including -aminophenol oxidase, laccase, and dye-decolorizing peroxidase.

Identification of the Protein Glycation Sites in Human Myoglobin as Rapidly Induced by d-Ribose.

Protein glycation is an important protein post-translational modification and is one of the main pathogenesis of diabetic angiopathy. Other than glycated hemoglobin, the protein glycation of other globins such as myoglobin (Mb) is less studied. The protein glycation of human Mb with ribose has not been reported, and the glycation sites in the Mb remain unknown.

Noncoding RNAs in triple negative breast cancer: Mechanisms for chemoresistance.

Triple-negative breast cancer (TNBC) is the most aggressive subtype among breast cancers with high recurrence and this condition is partly due to chemoresistance. Therefore, fully understanding the mechanism of TNBC-resistance is the key to overcoming chemoresistance, which will be an effective strategy for TNBC therapy. Various potential mechanisms involved in the chemoresistance of TNBC have been investigated and indicated that noncoding RNAs (ncRNAs) especially microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) take part in most TNBC resistance.

Biotransformation of Lignin by an Artificial Heme Enzyme Designed in Myoglobin With a Covalently Linked Heme Group.

The conversion of Kraft lignin in plant biomass into renewable chemicals, aiming at harvesting aromatic compounds, is a challenge process in biorefinery. Comparing to the traditional chemical methods, enzymatic catalysis provides a gentle way for the degradation of lignin. Alternative to natural enzymes, artificial enzymes have been received much attention for potential applications.

circ-PRKCI targets miR-1294 and miR-186-5p by downregulating FOXK1 expression to suppress glycolysis in hepatocellular carcinoma.

Numerous human circular RNAs (circRNAs/circ) have been functionally characterized. However, the potential role of circ-protein kinase C iota (PRKCI) in hepatocellular carcinoma (HCC) remains unknown. The effects of each transfection and expression levels of circ-PRKCI, microRNA (miR)-1294, miR-186-5p and forkhead box K1 (FOXK1) in HCC cells were analyzed using reverse transcription-quantitative PCR analysis.

Conversion of Human Neuroglobin into a Multifunctional Peroxidase by Rational Design.

Protein design has received much attention in the last decades. With an additional disulfide bond to enhance the protein stability, human A15C neuroglobin (Ngb) is an ideal protein scaffold for heme enzyme design. In this study, we rationally converted A15C Ngb into a multifunctional peroxidase by replacing the heme axial His64 with an Asp residue, where Asp64 and the native Lys67 at the heme distal site were proposed to act as an acid-base catalytic couple for HO activation.

The importance of Asn52 in the structure-function relationship of human cytochrome .

The function of the highly conserved residue Asn52 in human cytochrome (H-Cyt ) is not fully understood. Herein, we show that the naturally occurring variant N52S H-Cyt has a perturbed secondary structure, with a small fraction of high-spin species. Remarkably, it exhibits an enhanced peroxidase activity by 3-8-fold at neutral pH, as well as self-oxidation in reaction with HO.

A novel secretagogin/ATF4 pathway is involved in oxidized LDL-induced endoplasmic reticulum stress and islet β-cell apoptosis.

Excessive accumulation of cholesterol in β cells initiates endoplasmic reticulum (ER) stress and associated apoptosis. We have reported that excessive uptake of cholesterol by MIN6 cells decreases the expression of secretagogin (SCGN) and then attenuates insulin secretion. Here, we aimed to determine whether cholesterol-induced SCGN decrease is involved in the modulation of ER stress and apoptosis in pancreatic β cells.

Sorting nexins: A novel promising therapy target for cancerous/neoplastic diseases.

Sorting nexins (SNXs) are a diverse group of cytoplasmic- and membrane-associated phosphoinositide-binding proteins containing the PX domain proteins. The function of SNX proteins in regulating intracellular protein trafficking consists of endocytosis, endosomal sorting, and endosomal signaling. Dysfunctions of SNX proteins are demonstrated to be involved in several cancerous/neoplastic diseases.

Non-coding RNAs: Key regulators of aerobic glycolysis in breast cancer.

Although extensive research progress has been made in breast cancer in recent years, yet the morbidity and mortality rates of breast cancer are rising, making it the major disease that endangers women's health. Energy metabolism reprogramming is featured by a state termed "aerobic glycolysis" or the Warburg effect that glycolysis is preferred even under aerobic conditions in neoplastic diseases. Widely acknowledged as an emerging hallmark in cancers, this metabolic switch shows a sophisticated role in the pathogenesis of breast cancer.

PRMT2 inhibits the formation of foam cell induced by ox-LDL in RAW 264.7 macrophage involving ABCA1 mediated cholesterol efflux.

Objectives: Protein arginine methyltransferase 2 (PRMT2) is closely related to the occurrence and development of atherosclerosis. However, its underlying mechanisms remain to be elucidated. The purpose of this study is to observe the effect of overexpression of PRMT2 on the formation of foam cells and to explore its possible mechanism in RAW 264.