Project description:The recently identified histone modification lysine lactylation can be stimulated by L-lactate and glycolysis. Although the chemical group added upon lysine lactylation was originally proposed to be the L-enantiomer of lactate (KL-la), two isomeric modifications, lysine D-lactylation (KD-la), and N-ε-(carboxyethyl) lysine (Kce), also exist in cells, with their precursors being metabolites of glycolysis. The dynamic regulation and differences among these three modifications in response to hypoxia have not been investigated previously. In this study, we demonstrate that intracellular KL-la, but not KD-la or Kce, is upregulated in response to hypoxia. Depletion of glyoxalase enzymes, GLO1 and GLO2, had minimal impact on KD_x001E_la, Kce, or hypoxia-induced KL-la. Conversely, blocking glycolytic flux to L-lactate under hypoxic conditions by knocking out LDHA/B completely abolished the induction of KL-la, but increased KD-la and Kce. We further observed a correlation between the level of KL-la and HIF-1α expression under hypoxic conditions and when small molecules were used to stabilize HIF-1α in the normoxia condition. Our result demonstrated that there is a strong correlation between HIF-1α and KL-la in lung cancer tissues, and that patient samples with higher grade tend to have higher KL-la levels. Using a proteomics approach, we quantified 66 KL-la sites that were upregulated by hypoxia and demonstrated that p300/CBP contributes to hypoxia-induced KL-la. Collectively, our study demonstrates that KL-la, rather than KD-la or Kce, is the prevailing lysine lactylation in response to hypoxia. Our results therefore demonstrate a link between KL-la and the hypoxia-induced adaptation of tumor cells.
Project description:Hypoxia-induced M1 polarization of microglia and the resultant inflammatory response are pivotal mechanisms in the development of hypoxic-ischemic encephalopathy (HIE). Recent studies have identified lactylation of histones as a novel epigenetic modification, in which lactate groups are added to lysine residues on histones. Lactate, a product of cellular respiration, accumulates in the cytoplasm when cells experience hypoxia due to the conversion of pyruvate by lactate dehydrogenase. Therefore, histone lactylation may be involved in the pathogenesis of HIE. This study aims to investigate the role and mechanism of histone lactylation in hypoxia-induced M1 polarization of microglia and the associated inflammation, with the goal of providing new insights for the research and treatment of HIE.
Project description:Hypoxia promotes tumorigenesis and lactate accumulation in esophageal squamous cell carcinoma (ESCC). Lactate can induce histone lysine lactylation (Kla, a recently-identified histone marks) to regulate transcription. However, the functional consequence of histone Kla under hypoxia in ESCC remains to be explored. Here, we reveal that hypoxia facilitates histone H3K9la to enhance LAMC2 transcription for proliferation of ESCC. We found that global level of Kla was elevated under hypoxia, and thus identified the landscape of histone Kla in ESCC by quantitative proteomics. Furthermore, we show a significant increase of H3K9la level induced by hypoxia. Next, MNseq ChIP-seq and RNA-seq analysis suggest that H3K9la is enriched at the promoter of cell junction genes. Finally, we demonstrate that the histone H3K9la facilitates the expression of LAMC2 for ESCC invasion by in vivo and in vitro experiments. Briefly, our study reveal a vital role of histone Kla triggered by hypoxia in cancer.
Project description:Here we investigated the protein composition of the main pulmonary artery (MPA), distal pulmonary arteries (DPA) distal whole lung (DWL) of early stage hypoxia (using a neonatal bovine calf model) and late stage hypoxia (using adult steers with hypoxia-induced PH) using high resolution mass spectrometry. Compartment-resolved analysis allowed for quantitative measurements of proteins from cellular, soluble ECM and insoluble ECM fractions
Project description:Cancer-augmented lactogenesis has been described by the Warburg effect, and is associated with several major hallmarks of neoplasia. However, the non-metabolic functions of elevated lactate in physiology and disease remain unknown. Here we report histone lysine lactylation as a new type of epigenetic mechanism and as a functional destination for lactate. Histone lactylation is induced under glycolytic conditions such as hypoxia and M1 macrophage polarization. In the late phase of M1 macrophage polarization, increases in histone lactylation but not acetylation mark M2-like genes for activation. Our findings suggest a feedback mechanism of the innate immune system to switch from proinflammation to resolution through histone Kla-associated gene expression. This mechanism is implemented by the coopted function of lactate and histone lactylation in metabolism and epigenetics. Together, our study opens a new avenue for understanding function of lactate and glycolysis underlined diverse pathophysiological conditions.
Project description:To investigate the differentially expressed lncRNAs between hypoxia-induced Hep3B cells and normoxia cultured Hep3B cells, Arraystar Human LncRNA Microarray V5.0 is employed for the global profiling of human LncRNAs and protein-coding transcripts.
Project description:We explored the prognostic impact of the dynamic contrast enhanced MR imaging (DCE-MRI) parameter ABrix in cervical cancer combined with global gene expression data to reveal the underlying molecular phenotype of the parameter and construct a gene signature that reflected ABrix. Based on 78 cervical cancer patients subjected to curative chemoradiotherapy, we identified a prognostic ABrix parameter by pharmacokinetic analysis of DCE-MR images based on the Brix model, where tumors with low ABrix appeared to be most aggressive. Gene set enrichment analysis of 46 tumors with pairwise DCE-MRI and gene expression data showed a significant correlation between ABrix and the hypoxia gene sets, whereas gene sets related to proliferation, radioresistance, and wound healing were not significant. Hypoxia gene sets specific for cervical cancer created in cell culture experiments, including targets of the hypoxia inducible factor (HIF1M-NM-1) and the unfolded protein response (UPR), were the most significant. In the remaining 32 tumors, low ABrix was associated with upregulation of HIF1M-NM-1 protein expression, as assessed by immunohistochemistry, consistent with increased hypoxia. Based on the hypoxia gene sets, a signature of 31 genes that were upregulated in tumors with low ABrix was constructed. This DCE-MRI hypoxia gene signature showed prognostic impact in an independent validation cohort of 109 patients. Gene expression correlating with the DCE-MRI parameter ABrix were identified in 46 patients (DCE-MRI cohort) and used to find a hypoxia gene signature. The prognsotic impact of the gene signature was validated in an independent cohort of 109 patients (validation chort). Cell culture experiments were performed to generate cervical cancer specific gene lists associated with hypoxia (GSM897799 - GSM897804).