Astragaloside IV inhibits cell viability and glycolysis of hepatocellular carcinoma by regulating KAT2A-mediated succinylation of PGAM1.

BACKGROUND: Astragaloside IV (AS-IV) is one of the basic components of Astragali radix, that has been shown to have preventive effects against various diseases, including cancers. This study aimed to explore the role of AS-IV in hepatocellular carcinoma (HCC) and its underlying mechanism. METHODS: The cell viability, glucose consumption, lactate production, and extracellular acidification rate (ECAR) in SNU-182 and Huh7 cell lines were detected by specific commercial kits. Western blot was performed to analyze the succinylation level in SNU-182 and Huh7 cell lines. The interaction between lysine acetyltransferase (KAT) 2 A and phosphoglycerate mutase 1 (PGAM1) was evaluated by co-immunoprecipitation and immunofluorescence assays. The role of KAT2A in vivo was explored using a xenografted tumor model. RESULTS: The results indicated that AS-IV treatment downregulated the protein levels of succinylation and KAT2A in SNU-182 and Huh7 cell lines. The cell viability, glucose consumption, lactate production, ECAR, and succinylation levels were decreased in AS-IV-treated SNU-182 and Huh7 cell lines, and the results were reversed after KAT2A overexpression. KAT2A interacted with PGAM1 to promote the succinylation of PGAM1 at K161 site. KAT2A overexpression promoted the viability and glycolysis of SNU-182 and Huh7 cell lines, which were partly blocked following PGAM1 inhibition. In tumor-bearing mice, AS-IV suppressed tumor growth though inhibiting KAT2A-mediated succinylation of PGAM1. CONCLUSION: AS-IV inhibited cell viability and glycolysis in HCC by regulating KAT2A-mediated succinylation of PGAM1, suggesting that AS-IV might be a potential and suitable therapeutic agent for treating HCC.

Metabolic model guided CRISPRi identifies a central role for phosphoglycerate mutase in Chlamydia trachomatis persistence.

Upon nutrient starvation, Chlamydia trachomatis serovar L2 (CTL) shifts from its normal growth to a non-replicating form, termed persistence. It is unclear if persistence reflects an adaptive response or a lack thereof. To understand this, transcriptomics data were collected for CTL grown under nutrient-replete and nutrient-starved conditions. Applying K-means clustering on transcriptomics data revealed a global transcriptomic rewiring of CTL under stress conditions in the absence of any canonical global stress regulator. This is consistent with previous data that suggested that CTL's stress response is due to a lack of an adaptive response mechanism. To investigate the impact of this on CTL metabolism, we reconstructed a genome-scale metabolic model of CTL (iCTL278) and contextualized it with the collected transcriptomics data. Using the metabolic bottleneck analysis on contextualized iCTL278, we observed that phosphoglycerate mutase (pgm) regulates the entry of CTL to the persistence state. Our data indicate that pgm has the highest thermodynamics driving force and lowest enzymatic cost. Furthermore, CRISPRi-driven knockdown of pgm in the presence or absence of tryptophan revealed the importance of this gene in modulating persistence. Hence, this work, for the first time, introduces thermodynamics and enzyme cost as tools to gain a deeper understanding on CTL persistence. IMPORTANCE: This study uses a metabolic model to investigate factors that contribute to the persistence of Chlamydia trachomatis serovar L2 (CTL) under tryptophan and iron starvation conditions. As CTL lacks many canonical transcriptional regulators, the model was used to assess two prevailing hypotheses on persistence-that the chlamydial response to nutrient starvation represents a passive response due to the lack of regulators or that it is an active response by the bacterium. K-means clustering of stress-induced transcriptomics data revealed striking evidence in favor of the lack of adaptive (i.e., a passive) response. To find the metabolic signature of this, metabolic modeling pin-pointed pgm as a potential regulator of persistence. Thermodynamic driving force, enzyme cost, and CRISPRi knockdown of pgm supported this finding. Overall, this work introduces thermodynamic driving force and enzyme cost as a tool to understand chlamydial persistence, demonstrating how systems biology-guided CRISPRi can unravel complex bacterial phenomena.

PKM2 functions as a histidine kinase to phosphorylate PGAM1 and increase glycolysis shunts in cancer.

Phosphoglycerate mutase 1 (PGAM1) is a key node enzyme that diverts the metabolic reactions from glycolysis into its shunts to support macromolecule biosynthesis for rapid and sustainable cell proliferation. It is prevalent that PGAM1 activity is upregulated in various tumors; however, the underlying mechanism remains unclear. Here, we unveil that pyruvate kinase M2 (PKM2) moonlights as a histidine kinase in a phosphoenolpyruvate (PEP)-dependent manner to catalyze PGAM1 H11 phosphorylation, that is essential for PGAM1 activity. Moreover, monomeric and dimeric but not tetrameric PKM2 are efficient to phosphorylate and activate PGAM1. In response to epidermal growth factor signaling, Src-catalyzed PGAM1 Y119 phosphorylation is a prerequisite for PKM2 binding and the subsequent PGAM1 H11 phosphorylation, which constitutes a discrepancy between tumor and normal cells. A PGAM1-derived pY119-containing cell-permeable peptide or Y119 mutation disrupts the interaction of PGAM1 with PKM2 and PGAM1 H11 phosphorylation, dampening the glycolysis shunts and tumor growth. Together, these results identify a function of PKM2 as a histidine kinase, and illustrate the importance of enzyme crosstalk as a regulatory mode during metabolic reprogramming and tumorigenesis.

Phosphoglycerate mutase 1 promotes breast cancer progression through inducing immunosuppressive M2 macrophages.

Immunosuppressive tumor microenvironment (TME) contributes to tumor progression and causes major obstacles for cancer therapy. Phosphoglycerate mutase 1 (PGAM1) is a key enzyme involved in cancer metabolism while its role in remodeling TME remains unclear. In this study, we reported that PGAM1 suppression in breast cancer (BC) cells led to a decrease in M2 polarization, migration, and interleukin-10 (IL-10) production of macrophages. PGAM1 regulation on CCL2 expression was essential to macrophage recruitment, which further mediated by activating JAK-STAT pathway. Additionally, the CCL2/CCR2 axis was observed to participate in PGAM1-mediated immunosuppression via regulating PD-1 expression in macrophages. Combined targeting of PGAM1 and the CCL2/CCR2 axis led to a reduction in tumor growth in vivo. Furthermore, clinical validation in BC tissues indicated a positive correlation between PGAM1, CCL2 and macrophage infiltration. Our study provides novel insights into the induction of immunosuppressive TME by PGAM1 and propose a new strategy for combination therapies targeting PGAM1 and macrophages in BC.

Eicosapentaenoic acid-mediated activation of PGAM2 regulates skeletal muscle growth and development via the PI3K/AKT pathway.

Eicosapentaenoic acid regulates glucose uptake in skeletal muscle and significantly affects whole-body energy metabolism. However, the underlying molecular mechanism remains unclear. Here we report that eicosapentaenoic acid activates phosphoglycerate mutase 2, which mediates the conversion of 2-phosphoglycerate into 3-phosphoglycerate. This enzyme plays a pivotal role in glycerol degradation, thereby facilitating the proliferation and differentiation of satellite cells in skeletal muscle. Interestingly, phosphoglycerate mutase 2 inhibits mitochondrial metabolism, promoting the formation of fast-type muscle fibers. Treatment with eicosapentaenoic acid and phosphoglycerate mutase 2 knockdown induced opposite transcriptomic changes, most of which were enriched in the PI3K-AKT signaling pathway. Phosphoglycerate mutase 2 activated the PI3K-AKT signaling pathway, which inhibited the phosphorylation of FOXO1, and, in turn, inhibited mitochondrial function and promoted the formation of fast-type muscle fibers. Our results suggest that eicosapentaenoic acid promotes skeletal muscle growth and regulates glucose metabolism by targeting phosphoglycerate mutase 2 and activating the PI3K/AKT signaling pathway.

Phosphoglycerate mutase 5 aggravates alcoholic liver disease through disrupting VDAC-1-dependent mitochondrial integrity.

Alcoholic liver disease (ALD) poses a substantial global health challenge, with its pathogenesis deeply rooted in mitochondrial dysfunction. Our study explores the pivotal roles of Phosphoglycerate mutase family member 5 (Pgam5) and Voltage-Dependent Anion Channel 1 (VDAC1) in the progression of ALD, providing novel insights into their interplay and impact on mitochondrial integrity. We demonstrate that Pgam5 silencing preserves hepatocyte viability and attenuates ethanol-induced apoptosis, underscoring its detrimental role in exacerbating hepatocyte dysfunction. Pgam5's influence extends to the regulation of VDAC1 oligomerization, a key process in mitochondrial permeability transition pore (mPTP) opening, mitochondrial swelling, and apoptosis initiation. Notably, the inhibition of VDAC1 oligomerization through Pgam5 silencing or pharmacological intervention (VBIT-12) significantly preserves mitochondrial function, evident in the maintenance of mitochondrial membrane potential and reduced reactive oxygen species (ROS) production. In vivo experiments using hepatocyte-specific Pgam5 knockout (Pgam5hKO) and control mice reveal that Pgam5 deficiency mitigates ethanol-induced liver histopathology, inflammation, lipid peroxidation, and metabolic disorder, further supporting its role in ALD progression. Our findings highlight the critical involvement of Pgam5 and VDAC1 in mitochondrial dysfunction in ALD, suggesting potential therapeutic targets. While promising, these findings necessitate further research, including human studies, to validate their clinical applicability and explore broader implications in liver diseases. Overall, our study provides a significant advancement in understanding ALD pathophysiology, paving the way for novel therapeutic strategies targeting mitochondrial pathways in ALD.

PGAM5 exacerbates acute renal injury by initiating mitochondria-dependent apoptosis by facilitating mitochondrial cytochrome c release.

Acute kidney injury (AKI) is a worldwide public health problem characterized by the massive loss of tubular cells. However, the precise mechanism for initiating tubular cell death has not been fully elucidated. Here, we reported that phosphoglycerate mutase 5 (PGAM5) was upregulated in renal tubular epithelial cells during ischaemia/reperfusion or cisplatin-induced AKI in mice. PGAM5 knockout significantly alleviated the activation of the mitochondria-dependent apoptosis pathway and tubular apoptosis. Apoptosis inhibitors alleviated the activation of the mitochondria-dependent apoptosis pathway. Mechanistically, as a protein phosphatase, PGAM5 could dephosphorylate Bax and facilitate Bax translocation to the mitochondrial membrane. The translocation of Bax to mitochondria increased membrane permeability, decreased mitochondrial membrane potential and facilitated the release of mitochondrial cytochrome c (Cyt c) into the cytoplasm. Knockdown of Bax attenuated PGAM5 overexpression-induced Cyt c release and tubular cell apoptosis. Our results demonstrated that the increase in PGAM5-mediated Bax dephosphorylation and mitochondrial translocation was implicated in the development of AKI by initiating mitochondrial Cyt c release and activating the mitochondria-dependent apoptosis pathway. Targeting this axis might be beneficial for alleviating AKI.

RFX6 facilitates aerobic glycolysis-mediated growth and metastasis of hepatocellular carcinoma through targeting PGAM1.

BACKGROUND: Hepatocellular carcinoma (HCC) cells undergo reprogramming of glucose metabolism to support uncontrolled proliferation, of which the intrinsic mechanism still merits further investigation. Although regulatory factor X6 (RFX6) is aberrantly expressed in different cancers, its precise role in cancer development remains ambiguous. METHODS: Microarrays of HCC tissues were employed to investigate the expression of RFX6 in tumour and adjacent non-neoplastic tissues. Functional assays were employed to explore the role of RFX6 in HCC development. Chromatin immunoprecipitation, untargeted metabolome profiling and sequencing were performed to identify potential downstream genes and pathways regulated by RFX6. Metabolic assays were employed to investigate the effect of RFX6 on glycolysis in HCC cells. Bioinformatics databases were used to validate the above findings. RESULTS: HCC tissues exhibited elevated expression of RFX6. High RFX6 expression represented as an independent hazard factor correlated to poor prognosis in patients with HCC. RFX6 deficiency inhibited HCC development in vitro and in vivo, while its overexpression exerted opposite functions. Mechanistically, RFX6 bound to the promoter area of phosphoglycerate mutase 1 (PGAM1) and upregulated its expression. The increased PGAM1 protein levels enhanced glycolysis and further promoted the development of HCC. CONCLUSIONS: RFX6 acted as a novel driver for HCC development by promoting aerobic glycolysis, disclosing the potential of the RFX6-PGAM1 axis for therapeutic targeting.

PGAM1 Inhibition Promotes HCC Ferroptosis and Synergizes with Anti-PD-1 Immunotherapy.

The combination of immunotherapy and molecular targeted therapy exhibits promising therapeutic efficacy in hepatocellular carcinoma (HCC), but the underlying mechanism is still unclear. Here, phosphoglycerate mutase 1 (PGAM1) is identified as a novel immunometabolic target by using a bioinformatic algorithm based on multiple HCC datasets. PGAM1 is highly expressed in HCC and associated with a poor prognosis and a poor response to immunotherapy. In vitro and in vivo experiments indicate that targeting PGAM1 inhibited HCC cell growth and promoted the infiltration of CD8+ T-cells due to decreased enzymatic activity. Mechanistically, inhibition of PGAM1 promotes HCC cell ferroptosis by downregulating Lipocalin (LCN2) by inducing energy stress and ROS-dependent AKT inhibition, which can also downregulate Programmed death 1-ligand 1 (PD-L1). Moreover, an allosteric PGAM1 inhibitor (KH3) exhibits good antitumor effects in patient-derived xenograft (PDX) models and enhanced the efficacy of anti-PD-1 immunotherapy in subcutaneous and orthotopic HCC models. Taken together, the findings demonstrate that PGAM1 inhibition exerts an antitumor effect by promoting ferroptosis and CD8+ T-cell infiltration and can synergize with anti-PD-1 immunotherapy in HCC. Targeting PGAM1 can be a promising new strategy of "killing two birds with one stone" for HCC treatment.

PGAM5 deacetylation mediated by SIRT2 facilitates lipid metabolism and liver cancer proliferation.

Tumor metabolic reprogramming and epigenetic modification work together to promote tumorigenesis and development. Protein lysine acetylation, which affects a variety of biological functions of proteins, plays an important role under physiological and pathological conditions. Here, through immunoprecipitation and mass spectrum data, we show that phosphoglycerate mutase 5 (PGAM5) deacetylation enhances malic enzyme 1 (ME1) metabolic enzyme activity to promote lipid synthesis and proliferation of liver cancer cells. Mechanistically, we demonstrate that the deacetylase SIRT2 mediates PGAM5 deacetylation to activate ME1 activity, leading to ME1 dephosphorylation, subsequent lipid accumulation and the proliferation of liver cancer cells. Taken together, our study establishes an important role for the SIRT2-PGAM5-ME1 axis in the proliferation of liver cancer cells, suggesting a potential innovative cancer therapy.

Exosomal PGAM1 promotes prostate cancer angiogenesis and metastasis by interacting with ACTG1.

Tumor-derived exosomes and their contents promote cancer metastasis. Phosphoglycerate mutase 1 (PGAM1) is involved in various cancer-related processes. Nevertheless, the underlying mechanism of exosomal PGAM1 in prostate cancer (PCa) metastasis remains unclear. In this study, we performed in vitro and in vivo to determine the functions of exosomal PGAM1 in the angiogenesis of patients with metastatic PCa. We performed Glutathione-S-transferase pulldown, co-immunoprecipitation, western blotting and gelatin degradation assays to determine the pathway mediating the effect of exosomal PGAM1 in PCa. Our results revealed a significant increase in exosomal PGAM1 levels in the plasma of patients with metastatic PCa compared to patients with non-metastatic PCa. Furthermore, PGAM1 was a key factor initiating PCa cell metastasis by promoting invadopodia formation and could be conveyed by exosomes from PCa cells to human umbilical vein endothelial cells (HUVECs). In addition, exosomal PGAM1 could bind to γ-actin (ACTG1), which promotes podosome formation and neovascular sprouting in HUVECs. In vivo results revealed exosomal PGAM1 enhanced lung metastasis in nude mice injected with PCa cells via the tail vein. In summary, exosomal PGAM1 promotes angiogenesis and could be used as a liquid biopsy marker for PCa metastasis.

Phosphorylation-mediated regulation of the Bacillus anthracis phosphoglycerate mutase by the Ser/Thr protein kinase PrkC.

Bacillus anthracis Ser/Thr protein kinase PrkC is necessary for phenotypic memory and spore germination, and the loss of PrkC-dependent phosphorylation events affect the spore development. During sporulation, Bacillus sp. can store 3-Phosphoglycerate (3-PGA) that will be required at the onset of germination when ATP will be necessary. The Phosphoglycerate mutase (Pgm) catalyzes the isomerization of 2-PGA and 3-PGA and is important for spore germination as a key metabolic enzyme that maintains 3-PGA pool at later events. Therefore, regulation of Pgm is important for an efficient spore germination process and metabolic switching. While the increased expression of Pgm in B. anthracis decreases spore germination efficiency, it remains unexplored if PrkC could directly influence Pgm activity. Here, we report the phosphorylation and regulation of Pgm by PrkC and its impact on Pgm stability and catalytic activity. Mass spectrometry revealed Pgm phosphorylation on seven threonine residues. In silico mutational analysis highlighted the role of Thr459 residue towards metal and substrate binding. Altogether, we demonstrated that PrkC-mediated Pgm phosphorylation negatively regulates its activity that is essential to maintain Pgm in its apo-like isoform before germination. This study advances the role of Pgm regulation that represents an important switch for B. anthracis resumption of metabolism and spore germination.

MicroRNA-324-3p inhibits osteosarcoma progression by suppressing PGAM1-mediated aerobic glycolysis.

Osteosarcoma (OS) is the most common primary malignant neoplasm of the bone. Recent studies have indicated that the inhibitory effects of microRNA (miR)-324-3p could affect the development of numerous cancers. However, its biological roles and underlying mechanisms in OS progression remain unexplored. In this study, miR-324-3p expression was markedly reduced in OS cell lines and tissues. Functionally, miR-324-3p overexpression suppressed OS progression and was involved in the Warburg effect. Mechanistically, miR-324-3p negatively regulated phosphoglycerate mutase 1 (PGAM1) expression by targeting its 3'-UTR. Moreover, high expression of PGAM1 promoted OS progression and aerobic glycolysis, which were associated with inferior overall survival in patients with OS. Notably, the tumor suppressor functions of miR-324-3p were partially recovered by PGAM1 overexpression. In summary, the miR-324-3p/PGAM1 axis plays an important role in regulating OS progression by controlling the Warburg effect. Our results provide mechanistic insights into the function of miR-324-3p in glucose metabolism and subsequently on the progression of OS. Targeting the miR-324-3p/PGAM1 axis could be a promising molecular strategy for the treatment of OS.

A phosphoglycerate mutase 1 allosteric inhibitor overcomes drug resistance to EGFR-targeted therapy via disrupting IL-6/JAK2/STAT3 signaling pathway in lung adenocarcinoma.

Resistance to epidermal growth factor receptor (EGFR) inhibitors, from the first-generation erlotinib to the third generation osimertinib, is a clinical challenge in the treatment of patients with EGFR-mutant lung adenocarcinoma. Our previous work found that a novel allosteric inhibitor of phosphoglycerate mutase 1 (PGAM1), HKB99, restrains erlotinib resistance in lung adenocarcinoma cells. However, the role of HKB99 in osimertinib resistance and its underlying molecular mechanism remains to be elucidated. Herein, we found that IL-6/JAK2/STAT3 signaling pathway is aberrantly activated in both erlotinib and osimertinib resistant cells. Importantly, HKB99 significantly blocks the interaction of PGAM1 with JAK2 and STAT3 via the allosteric sites of PGAM1, which leads to inactivation of JAK2/STAT3 and thereby disrupts IL-6/JAK2/STAT3 signaling pathway. Consequently, HKB99 remarkably restores EGFR inhibitor sensitivity and exerts synergistic tumoricidal effect. Additionally, HKB99 alone or in combination with osimertinib down-regulated the level of p-STAT3 in xenograft tumor models. Collectively, this study identifies PGAM1 as a key regulator in IL-6/JAK2/STAT3 axis in the development of resistance to EGFR inhibitors, which could serve as a therapeutic target in lung adenocarcinoma with acquired resistance to EGFR inhibitors.

Phosphoglycerate mutase 5 facilitates mitochondrial dysfunction and neuroinflammation in spinal tissues after spinal cord injury.

Spinal cord injury (SCI) is a high incidence worldwide that causes a heavy physical and psychological burden to patients. It is urgent to further reveal the pathological mechanism and effective treatment of SCI. Mitochondrial dysfunction plays an important role in the disease progression of SCI. As a mitochondrial membrane protein, phosphoglycerate mutase 5 (PGAM5) is mainly involved in mitochondrial function and mitosis to modulate cellular physiological functions, but the roles of PGAM5 in spinal tissues remain to be unreported after SCI. The purpose of this study was to evaluate the role of PGAM5 in SCI mice and its relationship with neuroinflammation. The results showed that the mitochondrial membrane protein PGAM5 was involved in microglia activation after SCI, and PGAM5 deletion could improve mitochondrial dysfunction (including abnormal mtDNA, ATP synthases, and ATP levels, Cyt C expression, and ROS and rGSH levels) in spinal cord tissue after SCI, Arg1/iNOS mRNA level, iNOS expression, and pro-inflammatory cytokines TNF-α, IL-1ß, and IL-18 levels. In vitro, H2O2 increased TNF-α, IL-1ß, and IL-18 levels in BV2 cells, and PGAM5-sh and Nrf2 activators significantly reversed H2O2-induced iNOS expression and proinflammatory cytokine production. Furthermore, IP/Western blotting results revealed that PGAM5-sh treatment significantly reduced the interaction of PGAM5 with Nrf2 and enhanced the nuclear translocation of Nrf2 in BV2 cells. The data suggested that PGAM5 was involved in the cascade of oxidative stress and inflammatory response in microglia via facilitating the expression level of Nrf2 in the nucleus after SCI. It provided a reference for clarifying the pathological mechanism and therapeutic target of SCI.

PGAM5 regulates DRP1-mediated mitochondrial fission/mitophagy flux in lipid overload-induced renal tubular epithelial cell necroptosis.

The pathophysiology of renal lipid toxicity caused by excess adiposity is not well-understood. Necroptosis, a regulated form of cell death, is involved in injuring renal tubular epithelial cells (RTECs). Phosphoglycerate mutase 5 (PGAM5) is a key downstream effector of necroptosis. This study investigated the underlying mechanism of PGAM5 in promoting lipid-induced necroptosis in RTECs. HK2 cells (an immortalized proximal tubule epithelial cell line) were exposed to oleic acid (OA) to mimic the lipid overload environment in vitro. We found that OA suppressed HK2 cell proliferation, triggered cytoskeleton rupture and cell death. In OA-treated cells, upregulated expression of necroptosis pathway proteins, phosphorylated receptor-interacting protein-1/3 (pRIPK1/3), phosphorylated mixed lineage kinase domain-like protein (pMLKL), PGAM5, phosphorylated dynamin-related protein 1 (pDRP1S616), and downregulated pDRP1S637 expression were observed. This was accompanied by mitochondrial dysfunction (mitochondrial ROS overproduction and decreased mitochondrial membrane potential) and increased cellular necrosis, as reflected by Annexin V/ Propidium Iodide (PI) labeling. OA also induced the accumulation of LC3II and P62, blocking autophagosome fusion with lysosomes. Knockdown of PGAM5 could prevent these OA-induced changes. We propose inhibition of PGAM5 protects lipid-induced RTECs from necroptosis by reducing DRP1-mediated mitochondrial fission and improving mitophagy flux.

Ubiquitin specific protease 46 potentiates triple negative breast cancer development by stabilizing PGAM1-mediated glycolysis.

Triple-negative breast cancer (TNBC) is a malignancy with high metastasis rate and poor prognosis. Limited drugs are effective for the treatment of TNBC patients. Ubiquitin specific proteases (USPs) are important posttranscription modulators that promote protein stability by reducing the ubiquitination of the proteins. Aberrant expression of USPs is involved in the development of numerous cancers. However, it remains poorly understood on the role of USP46 in TNBC growth and metastasis. In this study, we explored the clinical relevance, function and molecular mechanisms of USP46 in TNBC. USP46 expression was increased in breast cancer tissues. High expression of USP46 was associated with the poorer prognosis of the patients. Overexpression and knockdown experiments demonstrated that USP46 was critical for TNBC cell growth, migration, and tumorigenesis. Mechanistically, USP46 enhanced the protein stability of phosphoglycerate mutase 1 (PGAM1) via direct interaction. Importantly, USP46 stimulated the glycolysis and promoted the malignant growth of TNBC cells through upregulation of PGAM1. Our study reveals that USP46/PGAM1 axis contributes to TNBC progression and is a potential target for the treatment of TNBC patients.

PGAM4 silencing inhibited glycolysis and chemoresistance to temozolomide in glioma cells.

Gliomas account for about 80% of malignant brain tumors. The incidence of a new brain tumor is 6.4 per 100,000 persons per year with an overall 5-year survival rate of 33.4%. Regardless of the great advances that have been made in recent years, the causes and pathogenesis of glioma remain unclear. Here we study how phosphoglycerate mutase 4 (PGAM4) contributes to glioma. Using a variety of methods to examine glioma cell viability, proliferation, apoptosis, glycolysis, as well as ChIP coanalysis with modified histone H3, we showed that PGAM4 was significantly upregulated in patients with glioma and associated with poor survival. Silencing PGAM4 attenuated cell viability, proliferation, and glycolysis in T98G cells and suppressed tumor growth in vivo, while overexpressing PGAM4 promoted cell viability, proliferation, and glycolysis in U251 cells via regulating glycolysis pathway. Study also revealed that PGAM4 was regulated by EP300-mediated modifications of H3K27ac. PGAM4 silencing inhibited cell viability and proliferation, suppressed tumor growth, and decreased chemoresistance to temozolomide in glioma cells through suppressing glycolysis.

Metabolite profiling of Arabidopsis mutants of lower glycolysis.

We have previously shown that in Arabidopsis the three enzymes of lower glycolysis namely phosphoglycerate mutase (PGAM), enolase and pyruvate kinase form a complex which plays an important role in tethering the mitochondria to the chloroplast. Given that the metabolism of these mutants, the complemented of pgam mutant and overexpression lines of PGAM were unclear, here, we present gas chromatography mass spectrometry-based metabolomics data of them alongside their plant growth phenotypes. Compared with wild type, both sugar and amino acid concentration are significantly altered in phosphoglycerate mutase, enolase and pyruvate kinase. Conversely, overexpression of PGAM could decrease the content of 3PGA, sugar and several amino acids and increase the content of alanine and pyruvate. In addition, the pgam mutant could not be fully complemented by either a nuclear target pgam, a side-directed-mutate of pgam or a the E.coli PGAM in term of plant phenotype or metabolite profiles, suggesting the low glycolysis complete formation is required to support normal metabolism and growth.

Necroptosis Contributes to LPS-Induced Activation of the Hypothalamic-Pituitary-Adrenal Axis in a Piglet Model.

Stressors cause activation of the hypothalamic-pituitary-adrenal (HPA) axis and a systemic inflammatory response. As a newly proposed cell death manner in recent years, necroptosis occurs in a variety of tissue damage and inflammation. However, the role of necroptosis in HPA axis activation remains to be elucidated. The aim of this study was to investigate the occurrence of necroptosis and its role in HPA activation in a porcine stress model induced by Escherichia coli lipopolysaccharide (LPS). Several typical stress behaviors like fever, anorexia, shivering and vomiting were observed in piglets after LPS injection. HPA axis was activated as shown by increased plasma cortisol concentration and mRNA expression of pituitary corticotropin-releasing hormone receptor 1 (CRHR1) and adrenal steroidogenic acute regulatory protein (StAR). The mRNA expression of tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß) and IL-6 in the hypothalamus, pituitary gland and adrenal gland was elevated by LPS, accompanied by the activation of necroptosis indicated by higher mRNA expression of necroptosis signals including receptor-interacting protein kinase (RIP) 1, RIP3, and phosphorylated mixed-lineage kinase domain-like protein (MLKL). Furthermore, necrostatin-1 (Nec-1), an inhibitor of necroptosis, inhibited necroptosis indicated by decreased mRNA levels of RIP1, RIP3, MLKL, and phosphoglycerate mutase family member 5 (PGAM5) in the hypothalamus, pituitary gland and adrenal gland. Nec-1 also decreased the mRNA expression of TNF-α and IL-ß and inhibited the activation of the HPA axis indicated by lower plasma cortisol concentration and mRNA expression of adrenal type 2 melanocortin receptor (MC2R) and StAR. These findings suggest that necroptosis is present and contributes to HPA axis activation induced by LPS. These findings provide a potential possibility for necroptosis as an intervention target for alleviating HPA axis activation and stress responses.