Phosphoglycerate mutase 5 exacerbates liver ischemia-reperfusion injury by activating mitochondrial fission.

Although the death of hepatocytes is a crucial trigger of liver ischemia-reperfusion (I/R) injury, the regulation of liver I/R-induced hepatocyte death is still poorly understood. Phosphoglycerate mutase 5 (PGAM5), a mitochondrial Serine/Threonine protein phosphatase, regulates mitochondrial dynamics and is involved in the process of both apoptosis and necrotic. However, it is still unclear what role PGAM5 plays in the death of hepatocytes induced by I/R. Using a PGAM5-silence mice model, we investigated the role of PGAM5 in liver I/R injury and its relevant molecular mechanisms. Our data showed that PGAM5 was highly expressed in mice with liver I/R injury. Silence of PGAM5 could decrease I/R-induced hepatocyte death in mice. In subcellular levels, the silence of PGAM5 could restore mitochondrial membrane potential, increase mitochondrial DNA copy number and transcription levels, inhibit ROS generation, and prevent I/R-induced opening of abnormal mPTP. As for the molecular mechanisms, we indicated that the silence of PGAM5 could inhibit Drp1(S616) phosphorylation, leading to a partial reduction of mitochondrial fission. In addition, Mdivi-1 could inhibit mitochondrial fission, decrease hepatocyte death, and attenuate liver I/R injury in mice. In conclusion, our data reveal the molecular mechanism of PGAM5 in driving hepatocyte death through activating mitochondrial fission in liver I/R injury.

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.

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.

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.

CircDUS2L (circ_0039908) promotes lung adenocarcinoma progression by upregulating PGAM1 by acting as a miR-590-5p molecular sponge.

Lung adenocarcinoma (LUAD) is usually found at the metastatic stage. Circular RNA dihydrouridine synthase 2-like (DUS2L) (circDUS2L) has been discovered to be upregulated in LUAD. Nevertheless, the function of circDUS2L in LUAD has not been verified. Levels of circDUS2L, microRNA-590-5p (miR-590-5p), and phosphoglycerate mutase 1 (PGAM1) mRNA were analyzed using quantitative real-time polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, metastasis, and invasion were assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT), colony formation, 5-ethynyl-2'-deoxyuridine (Edu), flow cytometry, and transwell assays. Protein levels were detected by western blotting. Cell glycolysis was analyzed by measuring cell glucose consumption, lactate production, and extracellular acidification rate (ECAR). The regulatory mechanism of circDUS2L in LUAD cells was analyzed by bioinformatics analysis, dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays. Xenograft assay was conducted to confirm the function of circDUS2L in vivo. CircDUS2L was highly expressed in LUAD tissues and cells. CircDUS2L silencing constrained xenograft tumor growth in vivo. CircDUS2L knockdown induced apoptosis, repressed viability, colony formation, proliferation, metastasis, invasion, and glycolysis of LUAD cells in vitro by releasing miR-590-5p via functioning as a miR-590-5p sponge. MiR-590-5p was lowly expressed in LUAD tissues and cells, and miR-590-5p mimic curbed malignant behaviors and glycolysis of LUAD cells by targeting PGAM1. PGAM1 was overexpressed in LUAD tissues and cells, and circDUS2L sponged miR-590-5p to regulate PGAM1 expression. CircDUS2L elevated PGAM1 expression through functioning as a miR-590-5p sponge, thus driving malignant behaviors and glycolysis of LUAD cells.

Surface-expressed phosphoglycerate mutase of Candida albicans binds to salivary DMBT1.

Candida albicans colonizes oral tissues and causes infectious diseases. Colonization of C. albicans on the oral mucosa and tooth enamel surfaces is established via the interaction between C. albicans adhesins and salivary proteins, forming a film on the oral tissues. Deleted in malignant brain tumors 1 (DMBT1), also known as salivary agglutinin or gp-340, belongs to the scavenger receptor cysteine-rich (SRCR) superfamily. In the oral cavity, immobilized DMBT1 on oral tissues causes microbial adherence. Recently, we demonstrated that C. albicans binds to DMBT1 and isolated a 25-kDa C. albicans adhesin involved in the interaction with the binding domain of DMBT1, namely, SRCRP2. In the present study, we searched for additional DMBT1-binding adhesins in C. albicans. The component isolated here had a molecular mass of 29 kDa and was found to be phosphoglycerate mutase (Gpm1). Isolated Gpm1 inhibited C. albicans binding to SRCRP2 and directly bound to SRCRP2 in a dose-dependent manner. Gpm1 localization on the C. albicans cell wall surface was confirmed by immunostaining. These results suggest that surface-expressed Gpm1 functions as an adhesin for the establishment of C. albicans cells on the oral mucosa and tooth enamel by binding to DMBT1.

Identification of human phosphoglycerate mutase 1 (PGAM1) inhibitors using hybrid virtual screening approaches.

PGAM1 plays a critical role in cancer cell metabolism through glycolysis and different biosynthesis pathways to promote cancer. It is generally known as a crucial target for treating pancreatic ductal adenocarcinoma, the deadliest known malignancy worldwide. In recent years different studies have been reported that strived to find inhibitory agents to target PGAM1, however, no validated inhibitor has been reported so far, and only a small number of different inhibitors have been reported with limited potency at the molecular level. Our in silico studies aimed to identify potential new PGAM1 inhibitors that could bind at the allosteric sites. At first, shape and feature-based models were generated and optimized by performing receiver operating characteristic (ROC) based enrichment studies. The best query model was then employed for performing shape, color, and electrostatics complementarity-based virtual screening of the ChemDiv database. The top two hundred and thirteen hits with greater than 1.2 TanimotoCombo score were selected and then subjected to structure-based molecular docking studies. The hits yielded better docking scores than reported compounds, were selected for subsequent structural similarity-based clustering analysis to select the best hits from each cluster. Molecular dynamics simulations and binding free energy calculations were performed to validate their plausible binding modes and their binding affinities with the PGAM1 enzyme. The results showed that these compounds were binding in the reported allosteric site of the enzyme and can serve as a good starting point to design better active selective scaffolds against PGAM1enzyme.

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.

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.

Phosphoglycerate mutase 5 initiates inflammation in acute kidney injury by triggering mitochondrial DNA release by dephosphorylating the pro-apoptotic protein Bax.

Acute kidney injury (AKI) is a worldwide public health problem characterized by excessive inflammation with no specific therapy in clinic. Inflammation is not only a feature of AKI but also an essential promoter for kidney deterioration. Phosphoglycerate mutase 5 (PGAM5) was up-regulated and positively correlated with kidney dysfunction in human biopsy samples and mouse kidneys with AKI. PGAM5 knockout in mice significantly alleviated ischemia/reperfusion-induced kidney injury, mitochondrial abnormality and production of inflammatory cytokines. Elevated PGAM5 was found to be mainly located in kidney tubular epithelial cells and was also related to inflammatory response. Knockdown of PGAM5 inhibited the hypoxia/reoxygenation-induced cytosolic release of mitochondrial DNA (mtDNA) and binding of mtDNA with the cellular DNA receptor cGAS in cultured cells. cGAS deficiency also attenuated the inflammation and kidney injury in AKI. Mechanistically, as a protein phosphatase, PGAM5 was able to dephosphorylate the pro-apoptotic protein Bax and facilitate its translocation to mitochondrial membranes, and then initiate increased mitochondrial membrane permeability and release of mtDNA. Leaked mtDNA recognized by cGAS then initiated its downstream-coupled STING pathway, a component of the innate immune system that functions to detect the presence of cytosolic DNA. Thus, our results demonstrated mtDNA release induced by PGAM5-mediated Bax dephosphorylation and the activation of cGAS-STING pathway as critical determinants of inflammation and kidney injury. Hence, targeting this axis may be useful for treating AKI.

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.

High-Resolution Crystal Structure of Muscle Phosphoglycerate Mutase Provides Insight into Its Nuclear Import and Role.

Phosphoglycerate mutase (PGAM) is a glycolytic enzyme converting 3-phosphoglycerate to 2-phosphoglycerate, which in mammalian cells is expressed in two isoforms: brain (PGAM1) and muscle (PGAM2). Recently, it was shown that besides its enzymatic function, PGAM2 can be imported to the cell nucleus where it co-localizes with the nucleoli. It was suggested that it functions there to stabilize the nucleolar structure, maintain mRNA expression, and assist in the assembly of new pre-ribosomal subunits. However, the precise mechanism by which the protein translocates to the nucleus is unknown. In this study, we present the first crystal structure of PGAM2, identify the residues involved in the nuclear localization of the protein and propose that PGAM contains a "quaternary nuclear localization sequence (NLS)", i.e., one that consists of residues from different protein chains. Additionally, we identify potential interaction partners for PGAM2 in the nucleoli and demonstrate that 14-3-3ζ/δ is indeed an interaction partner of PGAM2 in the nucleus. We also present evidence that the insulin/IGF1-PI3K-Akt-mTOR signaling pathway is responsible for the nuclear localization of PGAM2.

PGAM1 Promotes Glycolytic Metabolism and Paclitaxel Resistance via Pyruvic Acid Production in Ovarian Cancer Cells.

BACKGROUND: Enhanced glycolysis occurs in most human cancer cells and is related to chemoresistance. However, detailed mechanisms remain vague. METHODS: Using proteinomics analysis, we found that the glycolytic enzyme Phosphoglycerate mutase 1 (PGAM1) was highly expressed in the paclitaxel-resistant ovarian cancer cell line SKOV3-TR30, as compared to its parental cell line SKOV3. Cell Counting Kit-8 proliferation experiment, plasmids and siRNA transfection, pyruvic acid and lactic acid production detection, immunofluorescence staining of functional mitochondria and oxygen consumption rate and extracellular acidification rate measurement were uesd to assess the glycolytic metabolism and paclitaxel resistance in ovarian cancer cells. The expression and prognostic effect of PGAM1 in 180 ovarian cancer patients were analyzed. RESULTS: SKOV3-TR30 cells display higher glycolytic flux and lower mitochondrial function than SKOV3 cells. Down-regulation of PGAM1 in SKOV3-TR30 cells resulted in decreased paclitaxel resistance. Up-regulation of PGAM1 in SKOV3 cells led to enhanced paclitaxel resistance. Analysis of the glycolytic flux revealed that PGAM1-mediated pyruvic acid or lactic acid production could modulate the capabilities of ovarian cancer cell resistance to paclitaxel. Our data also show high expression of PGAM1 as significantly correlated with reduced overall survival and reduced progression free survival in ovarian cancer patients. CONCLUSIONS: PGAM1 acts to promote paclitaxel resistance via pyruvic acid and/or lactate production in ovarian cancer cells. Inhibiting PGAM1 may provide a new approach to favorably alter paclitaxel resistance in ovarian cancer.

Matrine induces hepatocellular carcinoma apoptosis and represses EMT and stemness through microRNA-299-3p/PGAM1 axis.

This study explored the impacts of matrine on hepatocellular carcinoma (HCC) cell growth, metastasis, epithelial-mesenchymal transition (EMT), and stemness through regulating the microRNA (miR)-299-3p/phosphoglycerate mutase 1 (PGAM1) axis. The association between miR-299-3p expression with the prognosis of HCC patients was studied. miR-299-3p and PGAM1 sequences were transfected into matrine-treated HCC cells, and cell proliferation, invasion, apoptosis, and stemness were detected, as well as protein expression of EMT- and stemness-related makers. The targeting relationship between miR-299-3p and PGAM1 was identified. Matrine elevated miR-299-3p expression, repressed proliferation, invasion, and anti-apoptosis of HCC cells, and constrained EMT and stemness in vitro. PGAM1 was a target of miR-299-3p. Repression of PGAM1 rescued the effects of miR-299-3p downregulation on HCC cells. Matrine stimulates HCC cell apoptosis and represses the process of EMT and stemness through the miR-299-3p/PGAM1 axis.

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.

Phosphoglycerate mutase 1 that is essential for glycolysis may act as a novel metabolic target for predicating poor prognosis for patients with gastric cancer.

BACKGROUND: To identify a novel marker for gastric cancer, we examined the usefulness of phosphoglycerate mutase 1 (PGAM1) as a potential diagnostic marker using isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics and evaluated its clinical significance. METHODS: Proteins from a discovery group of four paired gastric cancer tissues and adjacent gastric tissues were labeled with iTRAQ reagents and then identified and quantified using LC-MS/MS. The expression of PGAM1 was further validated in 139 gastric cancer patients using immunohistochemistry. Furthermore, the correlation of PGAM1 expression with clinical parameters was analyzed. Gene set enrichment analysis (GSEA) was performed to identify gene sets that were activated in PGAM1-overexpressing patients with gastric cancer. RESULTS: PGAM1 was significantly overexpressed in most cancers but particularly so in gastric cancer, with a sensitivity of 82.01% (95% confidence interval [CI]: 75.5%-88.5%) and specificity of 79.13% (95% CI: 72.3%-86%). Its expression was significantly associated with histological grade II and III tumors (p = 0.033), lymph node metastasis (p = 0.031), and TNM III-IV staging (p = 0.025). The area under the receiver operating characteristic (ROC) curve for the detection of PGAM1 overexpression in gastric cancer was 0.718 (p < 0.01). Furthermore, GSEA revealed that several important pathways such as glycolysis pathway and immune pathways were significantly enriched in patients with gastric cancer with PGAM1 overexpression. CONCLUSIONS: This study provided a sensitive method for detecting PGAM1, which may serve as a novel indicator for poor prognosis of gastric cancer, as well as a potent drug target for gastric cancer.

Schistosoma mansoni phosphoglycerate mutase: a glycolytic ectoenzyme with thrombolytic potential.

Schistosomiasis is a debilitating parasitic disease caused by intravascular flatworms called schistosomes (blood flukes) that affects >200 million people worldwide. Proteomic analysis has revealed the surprising presence of classical glycolytic enzymes - typically cytosolic proteins - located on the extracellular surface of the parasite tegument (skin). Immunolocalization experiments show that phosphoglycerate mutase (PGM) is widely expressed in parasite tissues and is highly expressed in the tegument. We demonstrate that live Schistosoma mansoni parasites express enzymatically active PGM on their tegumental surface. Suppression of PGM using RNA interference (RNAi) diminishes S. mansoni PGM (SmPGM) gene expression, protein levels, and surface enzyme activity. Sequence comparisons place SmPGM in the cofactor (2,3-bisphosphoglycerate)-dependent PGM (dPGM) family. We have produced recombinant SmPGM (rSmPGM) in an enzymatically active form in Escherichia coli. The Michaelis-Menten constant (Km) of rSmPGM for its glycolytic substrate (3-phosphoglycerate) is 0.85 mM ± 0.02. rSmPGM activity is inhibited by the dPGM-specific inhibitor vanadate. Here, we show that rSmPGM not only binds to plasminogen but also promotes its conversion to an active form (plasmin) in vitro. This supports the hypothesis that host-interactive tegumental proteins (such as SmPGM), by enhancing plasmin formation, may help degrade blood clots around the worms in the vascular microenvironment and thus promote parasite survival in vivo.

Title: La phosphoglycérate mutase de Schistosoma mansoni ­ une ectoenzyme glycolytique avec un potentiel thrombolytique. Abstract: La schistosomiase est une maladie parasitaire débilitante causée par des vers plats intravasculaires appelés schistosomes qui affecte plus de 200 millions de personnes dans le monde. L'analyse protéomique a révélé la présence surprenante d'enzymes glycolytiques classiques ­ typiquement des protéines cytosoliques ­ situées sur la surface extracellulaire du tégument du parasite. Des expériences d'immunolocalisation montrent que la phosphoglycérate mutase (PGM) est largement exprimée dans les tissus parasitaires et fortement exprimée dans le tégument. Nous démontrons que les parasites Schistosoma mansoni vivants expriment une PGM enzymatiquement active sur leur surface tégumentaire. La suppression de la PGM à l'aide de l'interférence ARN (ARNi) diminue l'expression du gène PGM de S. mansoni (SmPGM), les niveaux de protéines et l'activité enzymatique de surface. Les comparaisons de séquences placent la SmPGM dans la famille des PGM dépendantes du cofacteur (2,3-bisphosphoglycérate) (dPGM). Nous avons produit de la SmPGM recombinante (rSmPGM) sous une forme enzymatiquement active dans Escherichia coli. La constante de Michaelis-Menten (Km) de rSmPGM pour son substrat glycolytique (3-phosphoglycérate) est de 0,85 mM ± 0,02. L'activité de la rSmPGM est inhibée par le vanadate, un inhibiteur spécifique des dPGM. Ici, nous montrons que rSmPGM non seulement se lie au plasminogène mais favorise également sa conversion en une forme active (plasmine) in vitro. Cela soutient l'hypothèse selon laquelle les protéines tégumentaires interactives avec l'hôte (telles que SmPGM), en améliorant la formation de plasmine, peuvent aider à dégrader les caillots sanguins autour des vers dans le microenvironnement vasculaire et ainsi favoriser la survie du parasite in vivo.

PGAM1 regulation of ASS1 contributes to the progression of breast cancer through the cAMP/AMPK/CEBPB pathway.

Phosphoglycerate mutase 1 (PGAM1) is a crucial glycolytic enzyme, and its expression status has been confirmed to be associated with tumor progression and metastasis. However, the precise role and other biological functions of PGAM1 remain unclear. Here, we report that PGAM1 expression is upregulated and related to poor prognosis in patients with breast cancer (BC). Functional experiments showed that knockdown of PGAM1 could suppress the proliferation, invasion, migration, and epithelial-mesenchymal transition of BC cells. Through RNA sequencing, we found that argininosuccinate synthase 1 (ASS1) expression was markedly upregulated in BC cells following PGAM1 knockdown, and it is required to suppress the malignant biological behavior of BC cells. Importantly, we demonstrated that PGAM1 negatively regulates ASS1 expression through the cAMP/AMPK/CEBPB axis. In vivo experiments further validated that PGAM1 promoted tumor growth in BC by altering ASS1 expression. Finally, immunohistochemical analysis showed that downregulated ASS1 levels were associated with PGAM1 expression and poor prognosis in patients with BC. Our study provides new insight into the regulatory mechanism of PGAM1-mediated BC progression that might shed new light on potential targets and combination therapeutic strategies for BC treatment.

Phosphoglycerate mutase 5 promotes necroptosis in trophoblast cells through activation of dynamin-related protein 1 in early-onset preeclampsia.

OBJECTIVES: Placentae from patients with preeclampsia have increased susceptibility to necroptosis and phosphoglycerate mutase 5 (PGAM5) plays a role in many necrosis pathways. We determined whether PGAM5 promotes necroptosis of trophoblast cells and the underlying mechanisms in this study. METHODS: The injury model was established by treating JEG3 cells with hypoxia for 24 h. The functional measurements were assessed by the cell counting kit-8, propidium iodide (PI)/Annexin V staining, JC-1 staining and firefly luciferase ATP assay. The expression of proteins in human placentae and JEG3 cells was measured Western blot. PGAM5 was knocked down to study its role in hypoxia-induced necroptosis. RESULTS: The placentae from patients with preeclampsia showed up-regulation of PGAM5 and decreased levels of p-Drp1-S637, accompanied by increased necroptosis-relevant proteins expression. The expression of PGAM5 in JEG3 cells was up-regulated under hypoxia, which promoted dephosphorylation of Drp1 at Serine 637 residue, mitochondrial dysfunction (elevated ROS level and reduced mitochondrial membrane potential and ATP content) and cellular necroptosis (increased PI+ /Annexin V+ cells and decreased cell viability), accompanied by increased expression of necroptosis-relevant proteins; knockdown of PGAM5 attenuated these phenomena. CONCLUSIONS: Our results indicate that PGAM5 can promote necroptosis in trophoblast cells through, at least in part, activation of Drp1. It may be used as a new therapeutic target to prevent trophoblast dysfunction in preeclampsia.