Abstract Background Studies on DNA methylation following bariatric surgery have primarily focused on blood cells, while it is unclear to which extend it may reflect DNA methylation profiles in specific metabolically relevant organs such as adipose tissue (AT). Here, we investigated whether adipose tissue depots specific methylation changes after bariatric surgery are mirrored in blood. Methods Using Illumina 850K EPIC technology, we analysed genome-wide DNA methylation in paired blood, subcutaneous and omental visceral AT (SAT/OVAT) samples from nine individuals with severe obesity pre- and post-surgery. Findings The numbers and effect sizes of differentially methylated regions (DMRs) post-bariatric surgery were more pronounced in AT (SAT: 12,865 DMRs from -11.5 to 10.8%; OVAT: 14,632 DMRs from -13.7 to 12.8%) than in blood (9,267 DMRs from -8.8 to 7.7%). Cross-tissue DMRs implicated immune-related genes. Among them, 49 regions could be validated with similar methylation changes in blood from independent individuals. Fourteen DMRs correlated with differentially expressed genes in AT post bariatric surgery, including downregulation of PIK3AP1 in both SAT and OVAT. DNA methylation age acceleration was significantly higher in AT compared to blood, but remained unaffected after surgery. Interpretation Concurrent methylation pattern changes in blood and AT, particularly in immune-related genes, suggest blood DNA methylation mirrors inflammatory state of AT post-bariatric surgery.
Diabetic retinopathy, as one of the common complications of diabetes mellitus, is the leading cause of blindness in the working-age population worldwide. The disease is characterized by damage to retinal vasculature, which is associated with the activation of retina microglial and induces chronic neurodegeneration. Previous studies have identified the effects of activated microglial on the retinal neurons, but the cellular and molecular mechanisms underlying microglial activation is largely unknown. Here, we performed scRNA-seq on the retina of non-human primates with diabetes mellitus, and identified cell-type-specific molecular changes of the six major cell types. By identifying the ligand-receptor expression patterns among different cells, we established the interactome of the whole retina. The data showed that TNF-α signal mediated the activation of microglia through an autocrine manner. And we found TGFβ2, which was upregulated in cone dramatically by hyperglycemia, inhibited microglia activation at the early stage of diabetic retinopathy. In summary, our study is the first to profile cell-specific molecular changes and the cell-cell interactome of retina under diabetes mellitus, paving a way to dissect the cellular and molecular mechanisms underlying early-stage diabetic retinopathy.
Abstract Single-cell multi-omics sequencing can integrate transcriptome and epigenome to analyze the complex mechanisms underlying neuron development and regeneration, but most current methods are based on second-generation short-read sequencing, which has low efficiency in detecting RNA structural heterogeneity. Long-length sequencing can analyze RNA structures, but the throughput and the number of transcripts detected at the single-cell level are very low, and single-cell level epigenome profiling has not been accomplished either. Therefore, there is currently a lack of an effective method that can integrate RNA splicing and epigenetic modification to analyze the molecular mechanism of neural development. This study developed a single-cell multi-omics assay based on short-read sequencing for the simultaneous detection of single-cell full-length RNA isoforms and DNA accessibility. The accuracy of its resolution in RNA transcript structure can reach 94.5%, and the sensitivity of detecting single-cell gene expression is twice that of third-generation sequencing. And it can detect over 10,000 single nuclei at one run, enabling the effective integrated analysis of single-cell RNA isoforms and DNA accessibility at high throughput. We used this method to construct a multidimensional cell atlas of human retinal organoids, and found that gene expression and differential choices of isoforms of multiple fate-determining factors were significantly associated with chromatin accessibility. This method provides a new technical method for dissecting the multidimensional molecular mechanism of fate determination in neural cell development and regeneration.
Abstract The differences in transcription start sites (TSS) and transcription end sites (TES) among gene isoforms can affect the stability, localization, and translation efficiency of mRNA. Gene isoforms allow a single gene diverse functions across different cell types, and isoform dynamics allow different functions over time. However, methods to efficiently identify and quantify RNA isoforms genome-wide in single cells are still lacking. Here, we introduce single cell RNA Cap And Tail sequencing (scRCAT-seq), a method to demarcate the boundaries of isoforms based on short-read sequencing, with higher efficiency and lower cost than existing long-read sequencing methods. In conjunction with machine learning algorithms, scRCAT-seq demarcates RNA transcripts with unprecedented accuracy. We identified hundreds of previously uncharacterized transcripts and thousands of alternative transcripts for known genes, revealed cell-type specific isoforms for various cell types across different species, and generated a cell atlas of isoform dynamics during the development of retinal cones.
Glutamine and glutamate are interconverted by several enzymes and alterations in this metabolic cycle are linked to cardiometabolic traits. Herein, we show that obesity-associated insulin resistance is characterized by decreased plasma and white adipose tissue glutamine-to-glutamate ratios. We couple these stoichiometric changes to perturbed fat cell glutaminase and glutamine synthase messenger RNA and protein abundance, which together promote glutaminolysis. In human white adipocytes, reductions in glutaminase activity promote aerobic glycolysis and mitochondrial oxidative capacity via increases in hypoxia-inducible factor 1α abundance, lactate levels and p38 mitogen-activated protein kinase signalling. Systemic glutaminase inhibition in male and female mice, or genetically in adipocytes of male mice, triggers the activation of thermogenic gene programs in inguinal adipocytes. Consequently, the knockout mice display higher energy expenditure and improved glucose tolerance compared to control littermates, even under high-fat diet conditions. Altogether, our findings highlight white adipocyte glutamine turnover as an important determinant of energy expenditure and metabolic health.
Background White adipose tissue (WAT) regulates a plethora of physiological processes, which require the interaction between multiple resident cell types. In insulin resistance/type 2 diabetes, and upon WAT remodeling by weight alterations, the cellular and spatial organization of WAT is drastically altered. However, the cell types governing these changes and their link to insulin sensitivity remain largely unexplored.
Objective DNA methylation analysis is a valuable tool in elucidating molecular mechanisms underlying the beneficial effects of bariatric surgery. Yet it has primarily been studied in peripheral blood cells, although it is unclear to which extend it may reflect DNA methylation profiles in specific metabolically relevant organs such as adipose tissue. Here, we aimed to compare methylation signatures between blood and adipose tissue (AT) to test the hypothesis that AT methylation pattern changes after bariatric surgery are reflected in blood cell methylation signatures.
Abstract Reactive oxygen species (ROS) and oxidative stress accelerate cellular aging, but their impact on different tissues varies. The cornea, known for its robust antioxidant defense systems, is relatively resistant to age‐related diseases like cancer. However, the precise mechanisms by which the cornea maintains ROS homeostasis during aging remain unclear. Through comparative single‐cell transcriptomic analysis of the cornea and other tissues in young and old nonhuman primates, we identified that a ZNF281 coding transcriptomic program is specifically activated in cornea during aging. Further investigation revealed that ZNF281 forms a positive feedback loop with FOXO3 to sense elevated levels of ROS and mitigate their effects potentially by regulating the mitochondrial respiratory chain and superoxide dismutase (SOD) expression. Importantly, we observed that overexpression of ZNF281 in MSCs prevented cellular senescence. In summary, these findings open up possibilities for understanding tissue‐specific aging and developing new therapies targeting ROS damage.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
