Unraveling the Role of RNase L Knockout in Alleviating Immune Response Activation in Mice Bone Marrow after Irradiation.

Ionizing radiation (IR) induces severe hematopoietic injury by causing DNA and RNA damage as well as activating the immune responses, necessitating the development of effective therapeutic strategies. Ribonuclease L (RNase L) as an innate immune response pathway is triggered by exogenous and endogenous abnormal dsRNA under viral infection and dyshomeostasis, thereby activating the immune responses. Thus, we investigated the effect of RNase L on irradiation-induced bone marrow damage using RNase L knockout (RNase L-/-) mice. Phenotypic analysis revealed that RNase L knockout mitigates irradiation-induced injury in the bone marrow. Further investigation into the mechanism of RNase L by RNA-seq, qRT-PCR, and CBA analysis demonstrated that RNase L deficiency counteracts the upregulation of genes related to immune responses induced by irradiation, including cytokines and interferon-stimulated genes. Moreover, RNase L deficiency inhibits the increased levels of immunoglobulins in serum induced by irradiation. These findings indicate that RNase L plays a role in the immune response induced by irradiation in the bone marrow. This study further enhances our understanding of the biological functions of RNase L in the immune response induced by irradiation and offers a novel approach for managing irradiation-induced bone marrow injury through the regulation of RNase L activation.

ABRO1 promotes NLRP3 inflammasome activation through regulation of NLRP3 deubiquitination.

Deubiquitination of NLRP3 has been suggested to contribute to inflammasome activation, but the roles and molecular mechanisms are still unclear. We here demonstrate that ABRO1, a subunit of the BRISC deubiquitinase complex, is necessary for optimal NLRP3-ASC complex formation, ASC oligomerization, caspase-1 activation, and IL-1ß and IL-18 production upon treatment with NLRP3 ligands after the priming step, indicating that efficient NLRP3 activation requires ABRO1. Moreover, we report that ABRO1 deficiency results in a remarkable attenuation in the syndrome severity of NLRP3-associated inflammatory diseases, including MSU- and Alum-induced peritonitis and LPS-induced sepsis in mice. Mechanistic studies reveal that LPS priming induces ABRO1 binding to NLRP3 in an S194 phosphorylation-dependent manner, subsequently recruiting the BRISC to remove K63-linked ubiquitin chains of NLRP3 upon stimulation with activators. Furthermore, deficiency of BRCC3, the catalytically active component of BRISC, displays similar phenotypes to ABRO1 knockout mice. Our findings reveal an ABRO1-mediated regulatory signaling system that controls activation of the NLRP3 inflammasome and provide novel potential targets for treating NLRP3-associated inflammatory diseases.

Hydrogen peroxide and iron ions can modulate lipid peroxidation, apoptosis, and the cell cycle, but do not have a significant effect on DNA double-strand break.

Hydroxyl radical (·OH) generated by the Fenton reaction between transition metal ions and hydrogen peroxide (H2O2) can induce significant cellular damage. However, the specific mechanism of ·OH-induced cell death has not been systematically studied. In this study, we reacted FeSO4 and Fe3O4 magnetic nanoparticles with H2O2 and found that ·OH generated from the intracellular Fenton reaction can lead to significant cell death. The Fenton reaction between Fe2+ with H2O2 resulted in a shift in lipid peroxidation and cell cycle arrest. It is noteworthy that the ·OH generated from the Fenton reaction triggered severe apoptosis but did not lead to DNA double-strand breakage. Our results suggest that the Fenton reaction had acute cytotoxicity, which was primarily due to ·OH produced from the Fenton reaction inducing lipid peroxidation and apoptosis and modulating the cell cycle, but not by inducing DNA damage.

GPS2 promotes erythroid differentiation by control of the stability of EKLF protein.

Erythropoiesis is a complex multistage process that involves differentiation of early erythroid progenitors to enucleated mature red blood cells, in which lineage-specific transcription factors play essential roles. Erythroid Krüppel-like factor (EKLF/KLF1) is a pleiotropic erythroid transcription factor that is required for the proper maturation of the erythroid cells, whose expression and activation are tightly controlled in a temporal and differentiation stage-specific manner. Here, we uncover a novel role of G-protein pathway suppressor 2 (GPS2), a subunit of the nuclear receptor corepressor/silencing mediator of retinoic acid and thyroid hormone receptor corepressor complex, in erythrocyte differentiation. Our study demonstrates that knockdown of GPS2 significantly suppresses erythroid differentiation of human CD34+ cells cultured in vitro and xenotransplanted in nonobese diabetic/severe combined immunodeficiency/interleukin-2 receptor γ-chain null mice. Moreover, global deletion of GPS2 in mice causes impaired erythropoiesis in the fetal liver and leads to severe anemia. Flow cytometric analysis and Wright-Giemsa staining show a defective differentiation at late stages of erythropoiesis in Gps2-/- embryos. Mechanistically, GPS2 interacts with EKLF and prevents proteasome-mediated degradation of EKLF, thereby increasing EKLF stability and transcriptional activity. Moreover, we identify the amino acids 191-230 region in EKLF protein, responsible for GPS2 binding, that is highly conserved in mammals and essential for EKLF protein stability. Collectively, our study uncovers a previously unknown role of GPS2 as a posttranslational regulator that enhances the stability of EKLF protein and thereby promotes erythroid differentiation.

Transcriptional regulation of human abraxas brother protein 1 expression by yin yang 1.

Abraxas brother protein 1 (ABRO1) is a subunit of the deubiquitinating enzyme BRCC36-containing isopeptidase complex and plays important roles in cellular responses to stress by interacting with its binding partners, such as ubiquitin-specific peptidase 7, p53, activating transcription factor 4, THAP-domain containing 5, and serine hydroxymethyltransferase. However, the transcriptional regulation of ABRO1 remains unexplored. In this study, we identified and characterized the core regulatory elements of the human ABRO1 gene and mapped them to the ABRO1 promoter region. Additionally, 5' rapid amplification of cDNA ends revealed that the transcriptional start site (TSS) was located -13 bp upstream from the start codon. Reporter gene, chromatin immunoprecipitation, and electrophoretic mobility shift assays demonstrated that ABRO1 transcription was regulated through cis-acting elements located in the region -89 to -59 bp upstream of the ABRO1 TSS and that these elements were targeted by yin yang 1 transcription factor (YY1). Moreover, YY1 overexpression increased human ABRO1 mRNA and protein expression, and small-interfering RNA-mediated downregulation of YY1 attenuated ABRO1 expression. These results suggested that YY1 positively regulated human ABRO1 expression by binding to cis-acting elements located in the ABRO1 TSS.

EDAG mediates Hsp70 nuclear localization in erythroblasts and rescues dyserythropoiesis in myelodysplastic syndrome.

During human erythroid maturation, Hsp70 translocates into the nucleus and protects GATA-1 from caspase-3 cleavage. Failure of Hsp70 to localize to the nucleus was found in Myelodysplastic syndrome (MDS) erythroblasts and can induce dyserythropoiesis, with arrest of maturation and death of erythroblasts. However, the mechanism of the nuclear trafficking of Hsp70 in erythroblasts remains unknown. Here, we found the hematopoietic transcriptional regulator, EDAG, to be a novel binding partner of Hsp70 that forms a protein complex with Hsp70 and GATA-1 during human normal erythroid differentiation. EDAG overexpression blocked the cytoplasmic translocation of Hsp70 induced by EPO deprivation, inhibited GATA-1 degradation, thereby promoting erythroid maturation in an Hsp70-dependent manner. Furthermore, in myelodysplastic syndrome (MDS) patients with dyserythropoiesis, EDAG is dramatically down-regulated, and forced expression of EDAG has been found to restore the localization of Hsp70 in the nucleus and elevate the protein level of GATA-1 to a significant extent. In addition, EDAG rescued the dyserythropoiesis of MDS patients by increasing erythroid differentiation and decreasing cell apoptosis. This study demonstrates the molecular mechanism of Hsp70 nuclear sustaining during erythroid maturation and establishes that EDAG might be a suitable therapeutic target for dyserythropoiesis in MDS patients.

Glycerol kinase enhances hepatic lipid metabolism by repressing nuclear receptor subfamily 4 group A1 in the nucleus.

Glycerol kinase (GYK) plays a critical role in hepatic metabolism by converting glycerol to glycerol 3-phosphate in an ATP-dependent reaction. GYK isoform b is the only glycerol kinase present in whole cells, and has a non-enzymatic moonlighting function in the nucleus. GYK isoform b acts as a co-regulator of nuclear receptor subfamily 4 group A1 (NR4A1) and participates in the regulation of hepatic glucose metabolism by protein-protein interaction with NR4A1. Herein, GYK expression was found to upregulate the expression of NR4A1-mediated lipid metabolism-related genes (SREBP1C, FASN, ACACA, and GPAM) in HEK293T and L02 cells, and in mouse in vivo studies. GYK expression increased blood levels of cholesterol, triglyceride, and high-density lipoprotein cholesterol, but not low-density lipoprotein cholesterol levels. It enhanced the transcriptional activity of Nr4a1 target genes by negatively cooperating with NR4A1 and its enzymatic activity or by other undefined moonlighting functions. This enhancement was observed in both normal and diabetic mice. We also found a feed-forward regulation loop between GYK and NR4A1, serving as part of a GYK-NR4A1 regulatory mechanism in hepatic metabolism. Thus, GYK regulates the effect of NR4A1 on hepatic lipid metabolism in normal and diabetic mice, partially through the cooperation of GYK and NR4A1.

NLRP3 is dispensable for d-galactosamine/lipopolysaccharide-induced acute liver failure.

The nucleotide-binding domain and leucine-rich repeat-containing family pyrin domain containing 3 (NLRP3) inflammasome is involved in various acute and chronic liver diseases, however, it is not clear whether NLRP3 contributes to d-Galactosamine (D-GalN) plus lipopolysaccharide (LPS)-induced acute liver failure (ALF). This study aims to investigate the role of NLRP3 inflammasome in D-GalN/LPS-induced fatal hepatitis. We found that Nlrp3-/- and WT mice showed similar mortality against a lethal dose of D-GalN/LPS treatment. Serum ALT and AST levels, as well as liver necrosis area and hepatocyte apoptosis, were not significantly different between Nlrp3-/- and WT mice at 6 h after D-GalN/LPS injection. Moreover, the numbers of intrahepatic F4/80+ cells and Ly6G+ cells were comparable in two genotype mice following D-GalN/LPS treatment. Besides, Nlrp3-/- mice had reduced IL-1ß levels but similar TNF-α, IL-6, and MCP-1 levels compared with WT mice upon D-GalN/LPS administration. Our findings revealed that NLRP3 ablation does not protect mice from D-GalN/LPS-induced fatal hepatitis and has a marginal effect on intrahepatic inflammatory response upon D-GalN/LPS treatment. This suggests that NLRP3 inflammasome does not appear to be a major contributor to D-GalN/LPS-induced ALF.

KeggExp: a web server for visual integration of KEGG pathways and expression profile data.

SUMMARY: Effective visualization is important for knowledge discovery when analysing expression profile data. However, existing tools for visually integrating expression profile data with KEGG pathway maps lack extensive interactive visualization operations. KeggExp simultaneously presents the pathway map of one pathway, dendrogram and heatmap of the genes in the pathway and scatter map of one gene; and also provides interactive operations for highlighting specific genes on the pathway map, including differentially-expressed genes, co-expressed genes selected from the heatmap and user-input genes. With KeggExp, researchers, including those without programming skills, can take advantage of its interactive operations to determine key genes or pathways when analysing expression profile data. AVAILABILITY AND IMPLEMENTATION: Freely available at http://www.fgvis.com/expressvis/KeggExp/. Language: JavaScript, python; Libraries: D3.js, Rxjs, Angular, Django, Django rest frame work, Scipy. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Glycerol kinase interacts with nuclear receptor NR4A1 and regulates glucose metabolism in the liver.

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.

PPIExp: A Web-Based Platform for Integration and Visualization of Protein-Protein Interaction Data and Spatiotemporal Proteomics Data.

Integrating spatiotemporal proteomics data with protein-protein interaction (PPI) data can help researchers make an in-depth exploration of their proteins of interest in a dynamic manner. However, there is still a lack of proper tools for the biologists who usually have few programming skills to construct a PPI network for a protein list, visualize active PPI subnetworks, and then select key nodes for further study. We propose a web-based platform named PPIExp that can automatically construct a PPI network, perform clustering analysis according to protein abundances, and perform functional enrichment analysis. More importantly, it provides multiple effective visualization interfaces, such as the interface to display the PPI network map, the interface to display a dendrogram and heatmap for the clustering result, and the interface to display the expression pattern of a selected protein. To visualize the active PPI subnetworks in specific space or time, it provides buttons to highlight the differentially expressed proteins under each condition on the network map. Additionally, to help researchers determine which proteins are worth further attention, PPIExp provides extensive one-click interactive operations to map node centrality measures to node size on the network and highlight three types of proteins, that is, the proteins in an enriched functional term, the coexpressed proteins selected from the dendgrogram and heatmap, and the proteins input by users. PPIExp is available at http://www.fgvis.com/expressvis/PPIExp .

CBLB502, a Toll-like receptor 5 agonist, offers protection against radiation-induced male reproductive system damage in mice.

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 2 levels and a decrease in the levels of DNA repair protein and proliferating cell nuclear antigen. Moreover, an IR-induced reduction in serum testosterone and superoxide dismutase levels and an increase in malondialdehyde 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.

Toll-like receptor 5 signaling restrains T-cell/natural killer T-cell activation and protects against concanavalin A-induced hepatic injury.

Toll-like receptor-5 (TLR5) signaling regulates the immune privileged status of the liver and is involved in hepatic immune disorders. However, the role of TLR5 has not yet been investigated in experimental models of concanavalin A (Con A)-mediated liver injury. Here, we show that TLR5 is highly up-regulated in the hepatic mononuclear cells of mice during Con A-induced hepatitis. Increased mortality and liver histopathology of TLR5-deficient mice correlated with excessive production of proinflammatory cytokines, suggesting that TLR5 knockout mice were more susceptible to Con A-induced hepatitis. We also report that administration of CBLB502, an exogenous TLR5 agonist, substantially alleviated Con A-mediated hepatitis in wild-type mice as shown by increased survival rates, reduced aminotransferase and proinflammatory cytokine production, impaired lymphocyte infiltration, and ameliorated hepatocyte necrosis and/or apoptosis. Mechanistic studies revealed that CBLB502 acts as a negative regulator in limiting T-cell/natural killer T-cell activity and cytokine production in the Con A-hepatitis model. Bone marrow transplantation experiments showed that TLR5 in bone marrow-derived cells contributed to the hepatoprotective efficacy of CBLB502 against Con A-induced liver injury. Moreover, interleukin-6 elevation induced by CBLB502 is an important protective factor against Con A-induced liver injury. In addition, we demonstrate that CBLB502 suppresses α-galactosylceramide-induced natural killer T cell-dependent inflammatory liver injury. CONCLUSION: The TLR5 signaling pathway plays an important role in T cell-mediated hepatic injury and may be exploited for therapeutic treatment of inflammatory liver diseases. (Hepatology 2017;65:2059-2073).

Serine 249 phosphorylation by ATM protein kinase regulates hepatocyte nuclear factor-1α transactivation.

Hepatocyte nuclear factor-1 alpha (HNF1α) exerts important effects on gene expression in multiple tissues. Several studies have directly or indirectly supported the role of phosphorylation processes in the activity of HNF1α. However, the molecular mechanism of this phosphorylation remains largely unknown. Using microcapillary liquid chromatography MS/MS and biochemical assays, we identified a novel phosphorylation site in HNF1α at Ser249. We also found that the ATM protein kinase phosphorylated HNF1α at Ser249 in vitro in an ATM-dependent manner and that ATM inhibitor KU55933 treatment inhibited phosphorylation of HNF1α at Ser249 in vivo. Coimmunoprecipitation assays confirmed the association between HNF1α and ATM. Moreover, ATM enhanced HNF1α transcriptional activity in a dose-dependent manner, whereas the ATM kinase-inactive mutant did not. The use of KU55933 confirmed our observation. Compared with wild-type HNF1α, a mutation in Ser249 resulted in a pronounced decrease in HNF1α transactivation, whereas no dominant-negative effect was observed. The HNF1αSer249 mutant also exhibited normal nuclear localization but decreased DNA-binding activity. Accordingly, the functional studies of HNF1αSer249 mutant revealed a defect in glucose metabolism. Our results suggested that ATM regulates the activity of HNF1α by phosphorylation of serine 249, particularly in glucose metabolism, which provides valuable insights into the undiscovered mechanisms of ATM in the regulation of glucose homeostasis.

Hepassocin is required for hepatic outgrowth during zebrafish hepatogenesis.

BACKGROUND & AIMS: Hepassocin (HPS) is a hepatotrophic growth factor that specifically stimulates hepatocyte proliferation and promotes liver regeneration after liver damage. In this paper, zebrafish were used to investigate the role of HPS in liver development. METHODS AND RESULTS: During zebrafish development, HPS expression is enriched in liver throughout hepatogenesis. Knockdown of HPS using its specific morpholino leads to a smaller liver phenotype. Further results showed that the HPS knockdown has no effect on the expression of the early endoderm marker gata6 and early hepatic marker hhex. In addition, results showed that the smaller-liver phenotype in HPS morphants was caused by suppression of cell proliferation, not induction of cell apoptosis. CONCLUSIONS: Current findings indicated that HPS is essential to the later stages of development in vertebrate liver organogenesis.

EDAG positively regulates erythroid differentiation and modifies GATA1 acetylation through recruiting p300.

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.

14-3-3ζ interacts with hepatocyte nuclear factor 1α and enhances its DNA binding and transcriptional activation.

14-3-3 proteins regulate numerous cellular processes through interaction with a variety of proteins, and have been identified as HNF1α binding partner by mass spectrometry analysis in our previous study. In the present study, the interaction between 14-3-3ζ and HNF1α has been further validated by in vivo and in vitro assays. Moreover, we have found that overexpression of 14-3-3ζ potentiated the transcriptional activity of HNF1α in cultured cells, and silencing of 14-3-3ζ by RNA interference in HepG2 cells specifically affected the HNF1α-dependent gene expression. Furthermore, we have demonstrated that 14-3-3ζ is recruited to endogenous HNF1α responsive promoters and enhances HNF1α binding to its cognate DNA sequences. In addition, we have also provided evidence that the association between HNF1α and 14-3-3ζ is phosphorylation-dependent. Taken together, these results suggest that 14-3-3ζ may be an endogenous physiologic regulator of HNF1α.

Expansion of the polyQ repeats in THAP11 forms intranuclear aggregation and causes cell G0/G1 arrest.

Polyglutamine diseases are a group of neurodegenerative disorders caused by expansion of a CAG repeat that encodes polyglutamine in each respective disease gene. The transcription factor THAP11, a member of THAP family, is involved in cell growth, ES cell pluripotency and embryogenesis. Previous studies suggest that THAP11 protein contains a 29-residue repeat polyglutamine motif and the number of polyglutamine ranges from 20 to 41 in Indian population. We have investigated the CAG numbers at the THAP11 locus in normal individuals and neurodegenerative disease patients of Chinese Han population and a 38Q expansion (THAP11(38Q)) was found in patients. Using fluorescence confocal-based cell imaging, THAP11(38Q) protein formed intranuclear inclusions easier than THAP11(29Q) in PC12 cells. Enhanced toxicity was investigated in THAP11(38Q)-expressing cells by growth inhibition and G0/G1 arrest. CREB-mediated transcription activity was inhibited by THAP11(38Q). The transcription factor, TBP, coactivator CBP, and chaperon protein, HSP70, could be recruited to THAP11(38Q). These results indicate that expansion of the polyglutamine in THAP11 forms intracellular aggregation and is toxic in PC12 cells, suggesting a putative role of THAP11 in polyglutamine disease.

Toll-like Receptor Agonist CBLB502 Protects Against Radiation-induced Intestinal Injury in Mice.

BACKGROUND/AIM: The small intestine is one of the organs most vulnerable to ionizing radiation (IR) damage. However, methods to protect against IR-induced intestinal injury are limited. CBLB502, a Toll-like receptor 5 (TLR5) agonist from Salmonella flagellin, exerts radioprotective effects on various tissues and organs. However, the molecular mechanisms by which CBLB502 protects against IR-induced intestinal injury remain unclear. Thus, this study aimed to elucidate the mechanisms underlying IR-induced intestinal injury and the protective effects of CBLB502 against this condition in mice. MATERIALS AND METHODS: Mice were administered 0.2 mg/kg CBLB502 before IR at different doses for different time points, and then the survival rate, body weight, hemogram, and histopathology of the mice were analyzed. RESULTS: CBLB502 reduced IR-induced intestinal injury. RNA-seq analysis revealed that different doses and durations of IR induced different regulatory patterns. CBLB502 protected against intestinal injury mainly after IR by reversing the expression of IR-induced genes and regulating immune processes and metabolic pathways. CONCLUSION: This study preliminarily describes the regulatory mechanism of IR-induced intestinal injury and the potential molecular protective mechanism of CBLB502, providing a basis for identifying the functional genes and molecular mechanisms that mediate protection against IR-induced injury.

Long non­coding RNA lung cancer­associated transcript 1 regulates ferroptosis via microRNA­34a­5p­mediated GTP cyclohydrolase 1 downregulation in lung cancer cells.

Ferroptosis, a recently discovered type of programmed cell death triggered by excessive accumulation of iron­dependent lipid peroxidation, is linked to several malignancies, including non­small cell lung cancer. Long non­coding RNAs (lncRNAs) are involved in ferroptosis; however, data on their role and mechanism in cancer therapy remains limited. Therefore, the aim of the present study was to identify ferroptosis­associated mRNAs and lncRNAs in A549 lung cancer cells treated with RAS­selective lethal 3 (RSL3) and ferrostatin­1 (Fer­1) using RNA sequencing. The results demonstrated that lncRNA lung cancer­associated transcript 1 (LUCAT1) was significantly upregulated in lung adenocarcinoma and lung squamous cell carcinoma tissues. Co­expression analysis of differentially expressed mRNAs and lncRNAs suggested that LUCAT1 has a crucial role in ferroptosis. LUCAT1 expression was markedly elevated in A549 cells treated with RSL3, which was prevented by co­incubation with Fer­1. Functionally, overexpression of LUCAT1 facilitated cell proliferation and reduced the occurrence of ferroptosis induced by RSL3 and Erastin, while inhibition of LUCAT1 expression reduced cell proliferation and increased ferroptosis. Mechanistically, downregulation of LUCAT1 resulted in the downregulation of both GTP cyclohydrolase 1 (GCH1) and ferroptosis suppressor protein 1 (FSP1). Furthermore, inhibition of LUCAT1 expression upregulated microRNA (miR)­34a­5p and then downregulated GCH1. These results indicated that inhibition of LUCAT1 expression promoted ferroptosis by modulating the downregulation of GCH1, mediated by miR­34a­5p. Therefore, the combination of knocking down LUCAT1 expression with ferroptosis inducers may be a promising strategy for lung cancer treatment.