Pyroptosis is mediated by gasdermins and serves a critical role in ionizing radiation (IR)‑induced damage in normal tissues, but its role in cancer radiotherapy and underlying mechanisms remains unclear. Long non‑coding (lnc) RNAs serve important roles in regulating the radiosensitivity of cancer cells. The present study aimed to investigate the mechanistic involvement of lncRNAs in IR‑induced pyroptosis in human colorectal cancer HCT116 cells. LncRNA, microRNA (miR)‑448 and gasdermin E (GSDME) levels were evaluated using reverse transcription‑quantitative polymerase chain reaction. Protein expression and activation of gasdermins were measured using western blotting. The binding association between miR‑448 and GSDME was assessed using the dual‑luciferase reporter assay. Pyroptosis was examined using phase‑contrast microscopy, flow cytometry, Cell Counting Kit‑8 assay and lactate dehydrogenase release assay. IR dose‑dependently induced GSDME‑mediated pyroptosis in HCT116 cells. GSDME was identified as a downstream target of miR‑448. LncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) was upregulated in response to IR and enhanced GSDME expression by negatively regulating miR‑448 expression. Notably, NEAT1 knockdown suppressed IR‑induced pyroptosis, full‑length GSDME expression and GSDME cleavage compared with that in irradiated cells. In addition, NEAT1 knockdown rescued the IR‑induced decrease in cell viability in HCT116 cells. The findings of the present study indicated that lncRNA NEAT1 modulates IR‑induced pyroptosis and viability in HCT116 cells via miR‑448 by regulating the expression, but not activation of GSDME. The present study provides crucial mechanistic insight into the potential role of lncRNA NEAT1 in IR‑induced pyroptosis.

CBLB502, a Toll-like receptor (TLR)5 agonist derived from Salmonella flagellin, was shown to protect mammalian hematopoietic and gastrointestinal systems from acute irradiation syndrome and to stimulate regeneration. To explore whether CBLB502 can improve testicular injuries caused by irradiation, mice were intraperitoneally injected with 0.2 mg/kg CBLB502 or vehicle control 30 min prior to applying 5.0 Gy ionizing radiation (IR). We observed these mice for the following 120 days and determined that CBLB502 pretreatment alleviated IR-induced oxidative stress, alleviated the distorted architecture of seminiferous tubules, reversed the decline of sperm quantity and quality, and helped recover male mouse fertility. Additionally, CBLB502 efficiently reduced DNA damage and chromosomal aberrations in IR-treated mice and their offspring. Due to the suppression of p53-dependent apoptosis, in IR-treated mice, CBLB502 was shown to significantly activate the nuclear factor kappa B (NFκB) pathway and reduce the apoptotic rate in association with an increase in anti-apoptotic B-cell lymphoma (BCL)2 levels and a decrease in the levels of DNA repair protein and proliferating cell nuclear antigen (PCNA). Moreover, an IR-induced reduction in serum testosterone and superoxide dismutase (SOD) levels and an increase in malondialdehyde (MDA) levels were considerably reversed in CBLB502-pretreated mice. No significant reverse effects were found in Tlr5 knockout mice, suggesting that protection of the testis against IR by CBLB502 is primarily dependent on the TLR5 signaling pathway. Our results may help further investigations into potential CBLB502 applications for the protection of the male reproductive system during radiotherapy.

Glycerol kinase (Gyk), consisting of 4 isoforms, plays a critical role in metabolism by converting glycerol to glycerol 3‐phosphate in an ATP‐dependent reaction. Only Gyk isoform b is present in whole cells, but its function in the nucleus remains elusive. Previous studies have shown that nuclear orphan receptor subfamily 4 group A member (NR4A)‐1 is an important regulator of hepatic glucose homeostasis and lipid metabolism in adipose tissue. We aimed to elucidate the functional interaction between nuclear Gyk and NR4A1 during hepatic gluconeogenesis in the unfed state and diabetes. We identified nuclear Gyk as a novel corepressor of NR4A1 in the liver; moreover, this recruitment was dependent on the C‐terminal ligand‐binding domain instead of the N‐terminal activation function 1 domain, which interacts with other NR4A1 coregulators. NR4A1 transcriptional activity was inhibited by Gyk via protein‐protein interaction but not enzymatic activity. Moreover, Gyk overexpression suppressed NR4A1 ability to regulate the expression of target genes involved in hepatic gluconeogenesis in vitro and in vivo as well as blood glucose regulation, which was observed in both unfed and diabetic mice. These results highlight the moonlighting function of nuclear Gyk, which was found to act as a coregulator of NR4A1, participating in the regulation of hepatic glucose homeostasis in the unfed state and diabetes.—Miao, L., Yang, Y., Liu, Y., Lai, L., Wang, L., Zhan, Y., Yin, R., Yu, M., Li, C., Yang, X., Ge, C. Glycerol kinase interacts with nuclear receptor NR4A1 and regulates glucose metabolism in the liver. FASEB J. 33, 6736–6747 (2019). www.fasebj.org

Erythroid differentiation‐associated gene (EDAG) has been considered to be a transcriptional regulator that controls hematopoietic cell differentiation, proliferation, and apoptosis. The role of EDAG in erythroid differentiation of primary erythroid progenitor cells and in vivo remains unknown. In this study, we found that EDAG is highly expressed in CMPs and MEPs and upregulated during the erythroid differentiation of CD34⁺ cells following erythropoietin (EPO) treatment. Overexpression of EDAG induced erythroid differentiation of CD34⁺ cells in vitro and in vivo using immunodeficient mice. Conversely, EDAG knockdown reduced erythroid differentiation in EPO‐treated CD34⁺ cells. Detailed mechanistic analysis suggested that EDAG forms complex with GATA1 and p300 and increases GATA1 acetylation and transcriptional activity by facilitating the interaction between GATA1 and p300. EDAG deletion mutants lacking the binding domain with GATA1 or p300 failed to enhance erythroid differentiation, suggesting that EDAG regulates erythroid differentiation partly through forming EDAG/GATA1/p300 complex. In the presence of the specific inhibitor of p300 acetyltransferase activity, C646, EDAG was unable to accelerate erythroid differentiation, indicating an involvement of p300 acetyltransferase activity in EDAG‐induced erythroid differentiation. ChIP‐PCR experiments confirmed that GATA1 and EDAG co‐occupy GATA1‐targeted genes in primary erythroid cells and in vivo. ChIP‐seq was further performed to examine the global occupancy of EDAG during erythroid differentiation and a total of 7,133 enrichment peaks corresponding to 3,847 genes were identified. Merging EDAG ChIP‐Seq and GATA1 ChIP‐Seq datasets revealed that 782 genes overlapped. Microarray analysis suggested that EDAG knockdown selectively inhibits GATA1‐activated target genes. These data provide novel insights into EDAG in regulation of erythroid differentiation. Stem Cells 2014;32:2278–2289