Genome-wide Analysis Reflects Novel 5-Hydroxymethylcytosines Implicated in Diabetic Nephropathy

Long-term complications of type 2 diabetes (T2D) are the major causes for T2D-related disability and mortality. Notably, diabetic nephropathy (DN) has become the most frequent cause of end-stage renal disease (ESRD) in most countries. Understanding epigenetic contributors to DN can provide novel insights into this complex disorder and lay the foundation for more effective monitoring tools and preventive interventions, critical for achieving the ultimate goal of improving patient care and reducing healthcare burden. We have used a selective chemical labeling technique (5hmC-Seal) to profile genome-wide distributions of 5-hydroxymethylcytosines (5hmC), a gene activation mark, in patient-derived circulating cell-free DNA (cfDNA). Differentially modified 5hmC genes were identified across T2D patients with DN (n = 12), T2D patients with non-DN vascular complications (non-DN) (n = 29), and T2D patients with no complications (controls) (n = 14). Specifically, differential 5hmC markers between DN and controls revealed relevant pathways such as NOD-like receptor signaling pathway and tyrosine metabolism. A ten-gene panel was shown to provide differential 5hmC patterns between controls and DN, as well as between controls and non-DN patients using a machine learning approach. The 5hmC profiles in cfDNA reflected novel DN-associated epigenetic modifications relevant to the disease pathogenesis of DN. Importantly, these findings in cfDNA, a convenient liquid biopsy, have the potential to be exploited as a clinically useful tool for predicting DN in high risk T2D patients. Keywords: diabetes, nephropathy, epigenetics, 5-hydroxymethylcytosine, cfDNA

Selective Chemical Labeling and Sequencing of 5-Hydroxymethylcytosine in DNA at Single-Base Resolution

5-Hydroxymethylcytosine (5hmC), the oxidative product of 5-methylcytosine (5mC) catalyzed by ten-eleven translocation enzymes, plays an important role in many biological processes as an epigenetic mediator. Prior studies have shown that 5hmC can be selectively labeled with chemically modified glucose moieties and enriched using click chemistry with biotin affinity approaches. Besides, DNA deaminases of the AID/APOBEC family can discriminate modified 5hmC bases from cytosine (C) or 5mC. Herein, we developed a method based on embryonic stem cell (ESC) whole-genome analysis, which could enrich 5hmC-containing DNA by selective chemical labeling and locate 5hmC sites at single-base resolution with enzyme-based deamination. The combination experimental design is an extension of previous methods, and we hope that this cost-effective single-base resolution 5hmC sequencing method could be used to promote the mechanism and diagnosis research of 5hmC.

Proteome of the Luminal Surface of the Blood–Brain Barrier

Interrogation of the molecular makeup of the blood–brain barrier (BBB) using proteomic techniques has contributed to the cataloguing and functional understanding of the proteins uniquely organized at this specialized interface. The majority of proteomic studies have focused on cellular components of the BBB, including cultured brain endothelial cells (BEC). Detailed proteome mapping of polarized BEC membranes and their intracellular endosomal compartments has led to an improved understanding of the processes leading to internalization and transport of various classes of molecules across the BBB. Quantitative proteomic methods have further enabled absolute and comparative quantification of key BBB transporters and receptors in isolated BEC and microvessels from various species. However, translational studies further require in vivo/in situ analyses of the proteins exposed on the luminal surface of BEC in vessels under various disease and treatment conditions. In vivo proteomics approaches, both profiling and quantitative, usually rely on ‘capturing’ luminally-exposed proteins after perfusion with chemical labeling reagents, followed by analysis with various mass spectrometry-based approaches. This manuscript reviews recent advances in proteomic analyses of luminal membranes of BEC in vitro and in vivo and their applications in translational studies focused on developing novel delivery methods across the BBB.

Chemical safety in the context of environmental goals of sustainable development

The aim of the article is to carry out a systematic analysis of the components of chemical safety in the context of the environmental aspect of sustainable development goals and to identify those components with the help of competent health professionals. Hazardous chemicals can travel for long distances, be accumulated in the environment as well as cause adverse effects on human health through food chains. The action of toxicants of inorganic and organic nature occurs due to the violation of metabolic processes, inhibition of enzymes, and biotransformation of xenobiotics into more toxic compounds. Physicians must be clearly aware of the relationship in the “toxicant-pathology” system; understand the molecular mechanisms of the hazardous chemicals action; use terminology regarding toxicological characteristics of toxicants; conduct educational, treatment, and prevention activities among the population; acquire information on regulations governing the management of chemical compounds. The next component of chemical safety is the knowledge of approaches to chemical labeling and safety measures for working with chemical products throughout their life cycle. Proper interpretation of the type and level of hazard will enable taking necessary precautions and following relevant safety rules while working with chemical products.

Small but effective: light-weight additives modulate prenucleation clusters by specific interactions on the molecular level

Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which additives regulate stability and composition of solid ACC and CaCO3 solutions simultaneously. Effective precipitation inhibition arises from pronounced interaction of additives with prenucleation clusters (PNC). Potent antiscalants specifically trigger and integrate into PNCs. Only PNC-interacting additives are traceable in solid ACC, considerably stabilizing ACC against transformation. This co-precipitation specificity facilitates a chemical labeling of PNCs, evidencing ACC as a molecular precipitate of PNCs. Our results reveal additive-cluster interactions that operate beyond established mechanistic conceptions and thus reassess the role of small-MW molecules in crystallization and especially in biomineralization while breaking grounds for new sustainable antiscalants.

Proteomic Characterization of Isolated Arabidopsis Clathrin-Coated Vesicles Reveals Evolutionarily Conserved and Plant Specific Components

In eukaryotes, clathrin-coated vesicles (CCVs) facilitate the internalization of material from the cell surface as well as the movement of cargo in post-Golgi trafficking pathways. This diversity of functions is partially provided by multiple monomeric and multimeric clathrin adaptor complexes that provide compartment and cargo selectivity. The adaptor-protein AP-1 complex operates as part of the secretory pathway at the trans-Golgi network, while the AP-2 complex and the TPLATE complex (TPC) jointly operate at the plasma membrane to execute clathrin-mediated endocytosis. Key to our further understanding of clathrin-mediated trafficking in plants will be the comprehensive identification and characterization of the network of evolutionarily conserved and plant-specific core and accessory machinery involved in the formation and targeting of CCVs. To facilitate these studies, we have analyzed the proteome of enriched trans-Golgi network/early endosome-derived and endocytic CCVs isolated from dividing and expanding suspension-cultured Arabidopsis cells. Tandem mass spectrometry analysis results were validated by differential chemical labeling experiments to identify proteins co-enriching with CCVs. Proteins enriched in CCVs included previously characterized CCV components and cargos such as the vacuolar sorting receptors in addition to conserved and plant-specific components whose function in clathrin-mediated trafficking has not been previously defined. Notably, in addition to AP-1 and AP-2, all subunits of the AP-4 complex, but not AP-3 or AP-5, were found to be in high abundance in the CCV proteome. The association of AP-4 with suspension-cultured Arabidopsis CCVs is further supported via additional biochemical data.