Obesity-induced insulin resistance via changes in the DNA methylation profile of insulin pathway genes.

BACKGROUND: Obesity has been shown to play a key role in the development of insulin resistance (IR). Abundant data implicate obesity in DNA hypermethylation at global and site-specific levels, including genes regulating insulin sensitivity. Deregulation of epigenetic marks implicates gene expression and changes in cell metabolism. OBJECTIVES: Our previous reports demonstrated that the strongest risk factor in the development of IR is BMI; accordingly, the objective of this study was to investigate the effect of obesity on DNA methylation and insulin sensitivity. MATERIAL AND METHODS: A study was carried out on lymphocytes (N-34) and visceral adipose tissue (VAT; N-35) of insulin-resistant subjects and healthy controls. Genetic material (DNA and RNA) was extracted from cells. Global and site-specific DNA methylation was analyzed with the use of restriction enzymes followed by real-time polymerase chain reaction (PCR). Gene expression was analyzed as relative mRNA level normalized to a housekeeping gene. RESULTS: Global DNA methylation increased in both types of tissue in obese and insulin-resistant individuals and correlated positively with IR. Two of the 3 investigated promoters of insulin pathway genes were hypermethylated, which correlated negatively with gene expression and positively with IR. The DNMT3a gene was upregulated in obese insulin-resistant individuals in both types of tissues and correlated positively with global DNA methylation. CONCLUSIONS: DNA methylation profile changed depending on body mass index (BMI) and influenced glucose metabolism and insulin sensitivity in VAT.

Preliminary analysis of polymorphism of STR markers in the population of domestic cats (Felis catus) in Lower Silesia.

AIM OF THE STUDY: Genetic tests play a crucial role in the crime investigation process and often provide the strongest evidence for case resolution. Although the majority of genetic analyses in the field of criminalistics focus on the human DNA, genetic identification of animals is becoming an increasingly common procedure. Domestic animals, which live around people, may be silent witnesses and even victims of criminal activity. Their typically limited value as evidence in such cases could radically change thanks to the possibility of using animal biological material present at the crime scene. In addition to forensic medicine, genetic identification methods of this type may also become a valuable tool in many other areas of life. Recently, there has been an increase in public interest in verifying the pedigree of animals, investigating poaching and illegal shooting of animals, e.g. protected wildcats and lynx, as well as illegal trade in animals. The main aims of the studies reported in this paper were to assess the degree of polymorphism of the analyzed STR markers in feline genetic material, and to perform a preliminary evaluation of their suitability for developing an original feline genetic identification test. MATERIAL AND METHODS: The studies involved an analysis of genetic material samples obtained from a population consisting of 123 unrelated cats representing various domestic cat breeds, living in the Lower Silesia region. The material collected from individual cats in the form of blood drops or buccal swabs was subjected to an analysis of five STR markers forming a single multiplex assay (FCA742, FCA744, F124, FCA732, FCA749). RESULTS: The results obtained for each marker separately were analyzed statistically and, using the 2 test, the concordance of the study population with the Hardy-Weinberg principle was evaluated. CONCLUSIONS: The findings demonstrate a significant potential of the analyzed markers for the development of genetic identification tests.