Project description:<p>Natural killer (NK) cells are forced to cope with different oxygen environments even under resting conditions. The adaptation to low oxygen is regulated by oxygen-sensitive transcription factors, the hypoxia-inducible factors (HIFs). The function of HIFs for NK cell activation and metabolic rewiring remains controversial. Activated NK cells are predominantly glycolytic, but the metabolic programs that ensure the maintenance of resting NK cells are enigmatic. By combining <em>in situ</em> metabolomic and transcriptomic analyses in resting murine NK cells, our study defines HIF-1a as a regulator of tryptophan metabolism and cellular nicotinamide adenine dinucleotide (NAD+) levels. The HIF-1a/NAD+ axis prevents ROS production during oxidative phosphorylation (OxPhos) and thereby blocks DNA damage and NK cell apoptosis under steadystate conditions. In contrast, in activated NK cells under hypoxia, HIF-1a is required for glycolysis, and forced HIF-1a expression boosts glycolysis and NK cell performance <em>in vitro</em> and <em>in vivo</em>. Our data highlight two distinct pathways by which HIF-1a interferes with NK cell metabolism. While HIF-1a-driven glycolysis is essential for NK cell activation, resting NK cell homeostasis relies on HIF-1a-dependent tryptophan/NAD+ metabolism.</p><p><br></p><p><strong>Linked cross omic data sets:</strong></p><p>RNA-seq data associated with this study are available in ArrayExpress (BioStudies): accession <a href='https://www.ebi.ac.uk/biostudies/arrayexpress/studies/E-MTAB-12082' rel='noopener noreferrer' target='_blank'>E-MTAB-12082</a>.</p>
Project description:Fumarate hydratase (FH) mutations predispose to renal cysts cancer. These cancers overexpress hypoxia-inducible factor-alpha (Hif-1a). We have generated a conditional Fh1 (mouse FH) knockout mice that develop renal cysts and overexpress Hif-1a. In order to identify the contribution of Hif-1a to cyst formation we have intercrossed our mice with conditional HIf-1a KO mice. We intercrossed Fh1/Hif1a mice with kidney specific cre recombinase (Ksp-Cre) and analysed kidney cyst formation. RNA was extracted from cysts from 4xFh1 KO, 4xFh1/Hif-1a KO and 4 control mice. For each comparison littermates were used and the animals were aged 15 weeks i.e. early cystic disease.
Project description:Fumarate hydratase (FH) mutations predispose to renal cysts cancer. These cancers overexpress hypoxia-inducible factor-alpha (Hif-1a). We have generated a conditional Fh1 (mouse FH) knockout mice that develop renal cysts and overexpress Hif-1a. In order to identify the contribution of Hif-1a to cyst formation we have intercrossed our mice with conditional HIf-1a KO mice.
Project description:General activation of hypoxia-inducible factor (HIF) pathways is classically associated with adverse prognosis in cancer and has been proposed to contribute to oncogenic drive. In clear cell renal carcinoma (CCRC) HIF pathways are upregulated by inactivation of the von-Hippel-Lindau tumour suppressor. However HIF-1a and HIF-2a have contrasting effects on experimental tumour progression. To better understand this paradox we examined pan-genomic patterns of HIF DNA binding and associated gene expression in response to manipulation of HIF-1a and HIF-2a and related the findings to CCRC prognosis. Our findings reveal distinct pan-genomic organization of HIF isoform-specific DNA binding at thousands of sites. Overall associations were observed between HIF-1a-specific binding, and genes associated with favourable prognosis and between HIF-2a-specific binding and adverse prognosis. However within each isoform-specific set, individual gene associations were heterogeneous in sign and magnitude, suggesting that activation of each HIF-a isoform contributes a highly complex mix of pro- and anti-tumorigenic effects ChIP and RNASeq of HIF-1a and HIF-2a transfection in 786-O cell lines
Project description:HIF-1a works as a stress-induced transcription factor to induce target genes mediating cell proliferation, meabolism and inflammation. To gain new insights into HIF-1a biology, we used high-throughput sequencing to analyze global HIF-1a transcriptional networks in WT or HIF-1a deficient bone marrow B cells under hypoxia or normoxia.
Project description:Based on the results of numerous clinical and preclinical analyses, the transcription factor HIF-1a has been identified as an important tumor-promoting factor and is considered to be an attractive target for cancer therapy. To further deconstruct the molecular nature of HIF-1a’s role in tumorigenesis, we have applied lentiviral shRNA transduction to establish HIF-1a-deficient gastric cancer cells. Interestingly, functional analyses failed to show a significant growth defect of HIF-1a-deficient gastric cancer cells in vitro and in vivo. These observations led us to propose that stable inactivation of HIF-1a resulted in efficient compensation enabling cell growth and, ultimately, tumor progression in a HIF-1a-independent manner. To better understand the mechanisms that control this compensation, we performed transcriptomics of control (“scrambled” (SCR)) and HIF-1a-deficient (HIF) gastric cancer cells. Analysis of hypoxia-inducible factor-1alpha (HIF-1a)-deficient gastric cancer cells under normoxia. The transcription factor HIF-1a is a key regulator of oxygen homeostasis and has been identified as an important tumor-promoting factor. Results provide insight into the role of HIF-1a in gastric carcinogenesis.
Project description:HIF-1 (Hypoxia-inducible factor 1) is the master regulator responding to hypoxic conditions. Here, we found that HIF-1A is citrullinated by peptidyl arginine deiminase 4 (PADI4) at arginine 698, promoting HIF-1A stabilization and thus HIF-1-driven tumor growth. The knockdown of PADI4 could dramatically decrease HIF-1 protein expression without affecting the mRNA level, and this could be rescued by the proteasome inhibitor MG132 treatment under hypoxia. And PADI4-HIF-1A interaction is critical for HIF-1A stability and tumor progression, depending on the enzymatic activity of PADI4 and the pocket structure of PADI4. DHE, an FDA-approved agent for the treatment of migraine, was found serve as a potential antitumor agent throgh disrupting PADI4-HIF-1A interaction and suppressing HIF-1A stability. Taken together, we found the anti-tumor effect of DHE due to its effect on blocking PADI4-HIF-1A interaction and downregulating HIF-1A pathway in cancer cells. To figure out the influence of DHE on liver cancer cell under hypoxia, we treated Hep3B cell lines with two does DHE in 6 hours under Hypoxia and extracted mRNA for furthur RNA seq.
Project description:HIF-1A and HIF-2A regulate both overlapping and unique target genes in response to hypoxia. In this dataset, we identify specific HIF-1A and HIF-2A target genes in glioblastoma cells.
Project description:HIF-1a activates genes under hypoxia and was hypothesized to regulate bone regeneration. Surprisingly, HET HIF-1a fracture calluses are larger, stronger and stiffer than WT HIF-1a calluses due to decreased apoptosis. These data identify apoptosis inhibition as a means to enhance bone regeneration. Introduction: Bone regeneration subsequent to fracture involves the synergistic activation of multiple signaling pathways. Localized hypoxia following fracture activates hypoxia-inducible factor 1 alpha (HIF-1a) leading to increased expression of HIF-1 target genes. We therefore hypothesized that HIF-1a is a key regulator of bone regeneration Materials and Methods: Fixed femoral fractures were generated in mice with partial HIF-1a deficiency (HET HIF-1a) and wild type littermates (WT HIF-1a). Fracture calluses and intact contralateral femurs from post fracture day (PFD) 21 and 28 (N=5-10) were subjected to MicroCT evaluation and 4-point bending in order to assess morphometric and mechanical properties. Molecular analyses were carried out on PFD 7, 10 and 14 samples (N=3) to determine differential gene expression at both mRNA and protein levels. Finally, TUNEL staining was performed on PFD 14 samples (N=2) to elucidate differential apoptosis. Results: Surprisingly, fracture calluses from HET HIF-1a mice exhibit greater mineralization and are larger, stronger and stiffer. Microarray analyses focused on hypoxia-induced genes revealed differential expression (between genotypes) of several genes associated with the apoptotic pathway. Real-time PCR confirmed these results, demonstrating higher expression of pro-apoptotic PP2A and lower expression of anti-apoptotic BCL2 in WT HIF-1a calluses. Subsequent TUNEL staining demonstrates that WT HIF-1a calluses contain larger numbers of TUNEL positive chondrocytes and osteoblasts than HET HIF-1a calluses. Conclusions: We conclude that partial HIF-1a deficiency results in decreased chondrocytic and osteoblastic apoptosis; thereby allowing the development of larger, stiffer calluses and enhancing bone regeneration. Furthermore, apoptosis inhibition may be a promising target for developing new treatments to accelerate bone regeneration. Keywords: Bone, Fracture, Apoptosis, Hypoxia, Microarray
Project description:Mitochondria fulfill vital metabolic functions and act as crucial cellular signaling hubs integrating their metabolic status into the cellular context. Here, we show that defective cardiolipin-remodeling, upon loss of the cardiolipin acyl transferase Tafazzin, mutes HIF-1a signaling in hypoxia. Tafazzin-deficiency does not affect posttranslational HIF-1a regulation but rather HIF-1a gene-expression, a dysfunction recapitulated in iPSCs-derived cardiomyocytes from Barth Syndrome patients with Tafazzin-deficiency. RNAseq analyses confirmed drastically altered signaling in Tafazzin mutant cells. In hypoxia, Tafazzin-deficient cells display reduced production of reactive oxygen species (ROS) perturbing NF-kB activation and concomitantly HIF-1a gene-expression. In agreement, Tafazzin-deficient mice hearts display reduced HIF-1a levels and undergo maladaptive hypertrophy with heart failure in response to pressure overload challenge. We conclude that defective mitochondrial cardiolipin-remodeling dampens HIF-1a signaling through inactivation of a non-canonical signaling pathway: Lack of NF-kB activation through reduced mitochondrial ROS production diminishes HIF-1a transcription.