Rationale: Monocyte infiltration into the subintimal space and their intracellular lipid accumulation are the most prominent features of atherosclerosis. To understand the pathophysiology of atherosclerotic disease, we need to understand the characteristics of lipid-laden foamy macrophages in the subintimal space during atherosclerosis. Objective: We sought to examine the transcriptomic profiles of foamy and non-foamy macrophages isolated from atherosclerotic intima. Methods and Results: Single-cell RNA-sequencing analysis of CD45+ leukocytes from murine atherosclerotic aorta revealed that there are macrophage subpopulations with distinct differentially expressed genes involved in various functional pathways. To specifically characterize the intimal foamy macrophages of plaque, we developed a lipid staining-based flow cytometric method for analyzing the lipid-laden foam cells of atherosclerotic aortas. We employed the fluorescent lipid probe BODIPY493/503 and assessed side-scattered light (SSC) as an indication of cellular granularity. BODIPYhiSSChi foamy macrophages were found residing in intima and expressing CD11c. Foamy macrophage accumulation determined by flow cytometry was positively correlated with the severity of atherosclerosis. Bulk RNA-seq analysis showed that compared with non-foamy macrophages, foamy macrophages expressed few inflammatory genes but many lipid-processing genes. Intimal non-foamy macrophages formed the major population expressing interleukin-1β and many other inflammatory transcripts in atherosclerotic aorta. Conclusions: RNA-seq analysis of intimal macrophages from atherosclerotic aorta revealed that lipid-loaded plaque macrophages are not likely the plaque macrophages that drive lesional inflammation.

O-linked-N-acetylglucosamine (O-GlcNAc) has emerged as a critical regulator of diverse cellular processes, but its role in embryonic stem cells (ESCs) and pluripotency has not been investigated. Here we show that O-GlcNAcylation directly regulates core components of the pluripotency network. Blocking O-GlcNAcylation disrupts ESC self-renewal and reprogramming of somatic cells to induced pluripotent stem cells. The core reprogramming factors Oct4 and Sox2 are O-GlcNAcylated in ESCs, but the O-GlcNAc modification is rapidly removed upon differentiation. O-GlcNAc modification of threonine 228 in Oct4 regulates Oct4 transcriptional activity and is important for inducing many pluripotency-related genes, including Klf2, Klf5, Nr5a2, Tbx3, and Tcl1. A T228A point mutation that eliminates this O-GlcNAc modification reduces the capacity of Oct4 to maintain ESC self-renewal and reprogram somatic cells. Overall, our study makes a direct connection between O-GlcNAcylation of key regulatory transcription factors and the activity of the pluripotency network.

research stage because even state-of-theart Li-S cells do not meet the standards of all key aspects in battery operation; [1][2][3][4] although gravimetric energy density has proven to surpass those of existing lithium-ion batteries, cycle life, roundtrip efficiency, and rate performance are required to be further improved in order to be integrated with emerging battery applications such as electric vehicles and drones. [5,6] A variety of electrode structures, [7][8][9][10][11][12][13][14][15][16][17][18][19][20] electrolyte conditions, [21][22][23][24][25][26][27][28] and separator treatments [29][30][31][32][33][34] have been introduced to address the fatal capacity fading associated with polysulfide dissolution, electrode volume expansion, and poor conductivity of sulfur. Some representative electrode designs to avoid these fading mechanisms include encapsulating elemental sulfur (S) in conductive porous media or nanomaterial assemblies [35,36] or synthesizing sulfur-embedded polymers. [37][38][39][40][41][42] Both strategies have improved cyclability mainly by mitigating polysulfide dissolution. However, complete encapsulation remains a technical challenge for the former approach, where inevitable defects could lead to polysulfide dissolution especially Polysulfide dissolution into the electrolyte and poor electric conductivity of elemental sulfur are well-known origins for capacity fading in lithium-sulfur batteries. Various smart electrode designs have lately been introduced to avoid these fading mechanisms, most of which demonstrate significantly improved cycle life. Nevertheless, an in-depth understanding on the effect of sulfur microstructure and nanoscale electron transport near sulfur is currently lacking. In this study, the authors report an organized nanocomposite comprising linear sulfur chains and oleylamine-functionalized reduced graphene oxide (O-rGO) to achieve robust cycling performance (81.7% retention after 500 cycles) as well as to investigate the reaction mechanism in different regimes, i.e., S 8 dissolution, polysulfide conversion, and Li 2 S formation. In the nanocomposite, linear sulfur chains terminate with 1,3-diisopropyl benzene are covalently linked to O-rGO. The comparison with control samples that do not contain either the capping of sulfur chains or O-rGO reveals the synergistic interplay between both treatments, simultaneously unveiling the distinct roles of confined sulfur nanodomains and their adjoining electron pathways in different reaction regimes.

Embryonic stem cells (ESCs) undergo coordinated epigenetic and metabolic changes to differentiate properly. However, the precise mechanisms by which these alterations are fine-tuned in the early stages of differentiation have not been identified. In this study, we demonstrate that phosphoserine aminotransferase 1 (Psat1), an Oct4/Sox2/Nanog (OSN) target protein, regulates changes in α-ketoglutarate (α-KG), determining the fate of mouse ESCs (mESCs). Maintaining Psat1 levels was essential for mESC self-renewal and pluripotency. Moderate knockdown (KD) of Psat1 in mESCs lowered DNA 5'-hydroxymethylcytosine (5'-hmC) and increased histone methylation levels by downregulating permissive amounts of α-KG, ultimately accelerating differentiation. We found that intracellular α-KG declined transiently during differentiation and that its dysregulation by treatment with dimethyl-α-KG impeded differentiation. Further, by in vivo teratoma formation assay, pluripotency of Psat1 KD mESCs was impaired, especially into the ectodermal lineage. Thus, we have established how Psat1 is regulated in maintaining intracellular α-KG levels and determining the fate of mESCs.

No abstract

In two-dimensional interfacial assemblies, there is an interplay between molecular ordering and interface geometry, which determines the final morphology and order of entire systems. Here we present the interfacial phenomenon of spontaneous facet formation in a water droplet driven by designed peptide assembly. The identified peptides can flatten the rounded top of a hemispherical droplet into a plane by forming a macroscopic two-dimensional crystal structure. Such ordering is driven by the folding geometry of the peptide, interactions of tyrosine and crosslinked stabilization by cysteine. We discover the key sequence motifs and folding structures and study their sequence-specific assembly. The well-ordered, densely packed, redox-active tyrosine units in the YYACAYY (H-Tyr-Tyr-Ala-Cys-Ala-Tyr-Tyr-OH) film can trigger or enhance chemical/electrochemical reactions, and can potentially serve as a platform to fabricate a molecularly tunable, self-repairable, flat peptide or hybrid film.

Among ALDH isoforms, ALDH1L1 in the folate pathway showed highly increased expression in non-small-cell lung cancer cells (NSCLC). Based on the basic mechanism of ALDH converting aldehyde to carboxylic acid with by-product NADH, we suggested that ALDH1L1 may contribute to ATP production using NADH through oxidative phosphorylation. ALDH1L1 knockdown reduced ATP production by up to 60% concomitantly with decrease of NADH in NSCLC. ALDH inhibitor, gossypol, also reduced ATP production in a dose dependent manner together with decrease of NADH level in NSCLC. A combination treatment of gossypol with phenformin, mitochondrial complex I inhibitor, synergized ATP depletion, which efficiently induced cell death. Pre-clinical xenograft model using human NSCLC demonstrated a remarkable therapeutic response to the combined treatment of gossypol and phenformin.

Myocyte enhancer factor 2 (MEF2) is a family of transcription factors that regulates many processes, including muscle differentiation. Due to its many target genes, MEF2D requires tight regulation of transcription activity over time and by location. Epigenetic modifiers have been suggested to regulate MEF2-dependent transcription via modifications to histones and MEF2. However, the modulation of MEF2 activity by lysine methylation, an important posttranslational modification that alters the activities of transcription factors, has not been studied. We report the reversible lysine methylation of MEF2D by G9a and LSD1 as a regulatory mechanism of MEF2D activity and skeletal muscle differentiation. G9a methylates lysine-267 of MEF2D and represses its transcriptional activity, but LSD1 counteracts it. This residue is highly conserved between MEF2 members in mammals. During myogenic differentiation of C2C12 mouse skeletal muscle cells, the methylation of MEF2D by G9a decreased, on which MEF2D-dependent myogenic genes were upregulated. We have also identified lysine-267 as a methylation/demethylation site and demonstrate that the lysine methylation state of MEF2D regulates its transcriptional activity and skeletal muscle cell differentiation.