Chromatin immunoprecipitation with mouse adipocytes using hypotonic buffer to enrich nuclear fraction before fixation

Cost Minimized Immunoaffinity Purification of EPO and Its Analogs in Doping Control-A Step-by-Step Protocol for Human Urine and Blood

A cost minimized immunoaffinity protocol was developed, which allows the direct purification of ERAs (urinary and recombinant human EPO, Darbepoetin, EPO-Fc, CERA) from human urine. The method applies magnetic beads and needs no covalent immobilization of the capture antibody. It requires only 10 mL of urine, 1 μg of anti-EPO antibody, and 25 μL of bead slurry. The beads are coated with the capture antibody in advance and can be stored in the refrigerator for months without any loss of functionality. The protocol was fully validated in combination with SAR-PAGE and Western blotting using the biotinylated clone AE7A5 anti-EPO antibody. It is compliant with the criteria of TD2024EPO of the World Anti-Doping Agency (WADA) for the gel electrophoretic detection of ERAs. For each ERA, the achieved limit of detection (LOD) is at least one tenth of the minimum required performance limit (MRPL) of WADA, that is, 0.1 IU/L, 0.1 pg/mL, 0.5 pg/mL, and 0.5 pg/mL for rEPO, Darbepoetin, EPO-Fc, and CERA, respectively. After slight modification, the protocol is also applicable to serum and plasma and also fulfils the corresponding MRPLs of WADA for these matrices. Compared to commercial immunoaffinity purification kits for EPO, the material costs are significantly lower but with identical results.

NFIA in adipocytes reciprocally regulates mitochondrial and inflammatory gene program to improve glucose homeostasis

Adipose tissue is central to regulation of energy homeostasis. Adaptive thermogenesis, which relies on mitochondrial oxidative phosphorylation (Ox-Phos), dissipates energy to counteract obesity. On the other hand, chronic inflammation in adipose tissue is linked to type 2 diabetes and obesity. Here, we show that nuclear factor I-A (NFIA), a transcriptional regulator of brown and beige adipocytes, improves glucose homeostasis by upregulation of Ox-Phos and reciprocal downregulation of inflammation. Mice with transgenic expression of NFIA in adipocytes exhibited improved glucose tolerance and limited weight gain. NFIA up-regulates Ox-Phos and brown-fat-specific genes by enhancer activation that involves facilitated genomic binding of PPARγ. In contrast, NFIA in adipocytes, but not in macrophages, down-regulates proinflammatory cytokine genes to ameliorate adipose tissue inflammation. NFIA binds to regulatory region of the Ccl2 gene, which encodes proinflammatory cytokine MCP-1 (monocyte chemoattractant protein-1), to down-regulate its transcription. CCL2 expression was negatively correlated with NFIA expression in human adipose tissue. These results reveal the beneficial effect of NFIA on glucose and body weight homeostasis and also highlight previously unappreciated role of NFIA in suppressing adipose tissue inflammation.