DNA methylation and histone deacetylation regulating insulin sensitivity due to chronic cold exposure

Label-free quantitative detection and comparative analysis of lysine acetylation during the different life stages of Eimeria tenella

Proteome-wide lysine acetylation has been documented in apicomplexan parasite Toxoplasma gondii and Plasmodium falciparum. Here, we conducted the first lysine acetylome in unsporulated oocysts (USO), sporulated 7 h oocysts (SO 7h), sporulated oocysts (SO), sporozoites (S), and the second generation merozoites (SMG) of Eimeria tenella through a 4D label-free quantitative technique. Altogether, 8532 lysine acetylation sites on 2325 proteins were identified in E. tenella, among which 5445 sites on 1493 proteins were quantified. In addition, 557, 339, 478, 248, 241, and 424 differentially expressed proteins were identified in the comparisons SO7h vs USO, SO vs SO7h, SO vs USO, S vs SO, SMG vs S, and USO vs SMG, respectively. The bioinformatics analysis of the acetylome showed that the lysine acetylation is widespread on proteins of diverse functions. Moreover, the dynamic changes of lysine acetylome among E. tenella different life stages revealed significant regulation during the whole process of E. tenella growth and stage conversion. This study provides a beginning for the investigation of the regulate role of lysine acetylation in E. tenella and may provide new strategies for anticoccidiosis drug and vaccine development. Raw data are publicly available at iProX with the data set identifier PXD040368.

The Emerging Role of Epigenetics in Metabolism and Endocrinology

Each cell in a multicellular organism has its own phenotype despite sharing the same genome. Epigenetics is a somatic, heritable pattern of gene expression or cellular phenotype mediated by structural changes in chromatin that occur without altering the DNA sequence. Epigenetic modification is an important factor in determining the level and timing of gene expression in response to endogenous and exogenous stimuli. There is also growing evidence concerning the interaction between epigenetics and metabolism. Accordingly, several enzymes that consume vital metabolites as substrates or cofactors are used during the catalysis of epigenetic modification. Therefore, altered metabolism might lead to diseases and pathogenesis, including endocrine disorders and cancer. In addition, it has been demonstrated that epigenetic modification influences the endocrine system and immune response-related pathways. In this regard, epigenetic modification may impact the levels of hormones that are important in regulating growth, development, reproduction, energy balance, and metabolism. Altering the function of the endocrine system has negative health consequences. Furthermore, endocrine disruptors (EDC) have a significant impact on the endocrine system, causing the abnormal functioning of hormones and their receptors, resulting in various diseases and disorders. Overall, this review focuses on the impact of epigenetics on the endocrine system and its interaction with metabolism.

Brown and beige adipose tissue: a novel therapeutic strategy for obesity and type 2 diabetes mellitus

Mammalian adipose tissue can be divided into two major types, namely, white adipose tissue (WAT) and brown adipose tissue (BAT). According to classical view, the main function of WAT is to store excess energy in the form of triglycerides, while BAT is a thermogenic tissue that acts a pivotal part in maintaining the core body temperature. White adipocytes display high plasticity and can transdifferentiate into beige adipocytes which have many similar morphological and functional properties with brown adipocytes under the stimulations of exercise, cold exposure and other factors. This phenomenon is also known as 'browning of WAT'. In addition to transdifferentiation, beige adipocytes can also come from de novo differentiation from tissue-resident progenitors. Activating BAT and inducing browning of WAT can accelerate the intake of glycolipids and reduce the insulin secretion requirement, which may be a new strategy to improve glycolipids metabolism and insulin resistance of obese and type 2 diabetes mellitus (T2DM) patients. This review mainly discusses the significance of brown and beige adipose tissues in the treatment of obesity and T2DM, and focuses on the effect of the browning agent on obesity and T2DM, which provides a brand-new theoretical reference for the prevention and treatment of obesity and T2DM.

Histone modifications influence the insulin-signaling genes and are related to insulin resistance in human adipocytes

Insulin resistance (IR) is a state when the physiological amount of insulin is not sufficient to evoke proper action, that is, glucose uptake. Numerous conditions lead to IR, including epigenetic components. Epigenetic modifications, associated with obesity and IR are one of the main mechanisms leading to IR pathogenesis. The adipose tissue samples (subcutaneous (SAT) and visceral (VAT)) were collected during abdominal surgery from 40 patients of a wide range of BMI, age, and insulin resistance ratios (F = 9, M = 31). IR was induced in 3T3-L1 adipocytes and human adipocytes collected from SAT and VAT of healthy subjects. Global and site-specific histone modifications (H3K4me3 and H3K9/14ac) were determined. We found lower histone modifications in adipose tissue of IR patients. Furthermore, numerous genes regulating insulin action (PPARG, SLC2A4, ADIPOQ) were differently marked by histone methylation and acetylation. Moreover, we noticed that epigenetic changes appear as soon as 72 h following IR induction. The epigenetic changes appeared to be mediated through the SIRT family. Based on obtained results, the histone marks related to insulin resistance mostly concerned PPARG and SLC2A4 genes. Furthermore, our results proved a vital role of the SIRT family in insulin action and IR pathogenesis.

De Novo Lipogenesis as a Source of Second Messengers in Adipocytes

PURPOSE OF REVIEW

Obesity is a major risk factor for type 2 diabetes. Although adipose tissue allows storage of excess calories in periods of overnutrition, in obesity, adipose tissue metabolism becomes dysregulated and can promote metabolic diseases. This review discusses recent advances in understandings how adipocyte metabolism impacts metabolic homeostasis.

RECENT FINDINGS

The ability of adipocytes to synthesize lipids from glucose is a marker of metabolic fitness, e.g., low de novo lipogenesis (DNL) in adipocytes correlates with insulin resistance in obesity. Adipocyte DNL may promote synthesis of special "insulin sensitizing" signaling lipids that act hormonally. However, each metabolic intermediate in the DNL pathway (i.e., citrate, acetyl-CoA, malonyl-CoA, and palmitate) also has second messenger functions. Mounting evidence suggests these signaling functions may also be important for maintaining healthy adipocytes. While adipocyte DNL contributes to lipid storage, lipid precursors may have additional second messenger functions critical for maintaining adipocyte health, and thus systemic metabolic homeostasis.