Investigation of ENO2 as a promising novel marker for the progression of colorectal cancer with microsatellite instability-high.

BACKGROUND: Microsatellite instability-high (MSI-H) has emerged as a significant biological characteristic of colorectal cancer (CRC). Studies reported that MSI-H CRC generally had a better prognosis than microsatellite stable (MSS)/microsatellite instability-low (MSI-L) CRC, but some MSI-H CRC patients exhibited distinctive molecular characteristics and experienced a less favorable prognosis. In this study, our objective was to explore the metabolic transcript-related subtypes of MSI-H CRC and identify a biomarker for predicting survival outcomes. METHODS: Single-cell RNA sequencing (scRNA-seq) data of MSI-H CRC patients were obtained from the Gene Expression Omnibus (GEO) database. By utilizing the copy number variation (CNV) score, a malignant cell subpopulation was identified at the single-cell level. The metabolic landscape of various cell types was examined using metabolic pathway gene sets. Subsequently, functional experiments were conducted to investigate the biological significance of the hub gene in MSI-H CRC. Finally, the predictive potential of the hub gene was assessed using a nomogram. RESULTS: This study revealed a malignant tumor cell subpopulation from the single-cell RNA sequencing (scRNA-seq) data. MSI-H CRC was clustered into two subtypes based on the expression profiles of metabolism-related genes, and ENO2 was identified as a hub gene. Functional experiments with ENO2 knockdown and overexpression demonstrated its role in promoting CRC cell migration, invasion, glycolysis, and epithelial-mesenchymal transition (EMT) in vitro. High expression of ENO2 in MSI-H CRC patients was associated with worse clinical outcomes, including increased tumor invasion depth (p = 0.007) and greater likelihood of perineural invasion (p = 0.015). Furthermore, the nomogram and calibration curves based on ENO2 showed potential prognosis predictive performance. CONCLUSION: Our findings suggest that ENO2 serves as a novel prognostic biomarker and is associated with the progression of MSI-H CRC.

Correlations of Expression Levels of Lung Cancer Marker Gene Eno2 and Genes of Carcinogenesis and Apoptosis in the Hypothalamus of Mice with Depression-Like Behavior.

We experimentally demonstrated that chronic social stress during the development of a depression-like state enhances lung metastasis and modifies the expression of many carcinogenesis- and apoptosis-related genes in the hypothalamus of mice, including genes involved in lung cancer pathogenesis in humans. Analysis of the expression of genes encoding the major clinical markers of lung cancer in the hypothalamus of mice with depression-like behavior revealed increased expression of the Eno2 gene encoding neuron-specific enolase, a blood marker of lung cancer progression in humans. It was shown that the expression of this gene in the hypothalamus correlated with the expression of many carcinogenesis- and apoptosis-related genes. The discovered phenomenon may have a fundamental significance and requires further studies.

ENO1 promotes trophoblast invasion regulated by E2F8 in recurrent miscarriage.

Recurrent miscarriage (RM) is related to the dysfunction of extravillous trophoblast cells (EVTs), but the comprehensive mechanisms remain largely unexplored. We analyzed single-cell RNA sequencing (scRNA-seq), bulk RNA sequencing and microarray datasets obtained from Gene Expression Omnibus (GEO) database to explore the hub genes in the mechanisms of RM. We identified 1724 differentially expressed genes (DEGs) in EVTs from the RM, and they were all expressed along the trajectory of EVTs. These DEGs were associated with hypoxia and glucose metabolism. Single-cell Regulatory Network Inference and Clustering (SCENIC) analysis revealed that E2F transcription factor (E2F) 8 (E2F8) was a key transcription factor for these DEGs. And the expression of ENO1 can be positively regulated by E2F8 via RNA sequencing analysis. Subsequently, we performed immunofluorescence assay (IF), plasmid transfection, western blotting, chromatin immunoprecipitation (ChIP), real-time quantitative polymerase chain reaction (qRT-PCR), and transwell assays for validation experiments. We found that the expression of alpha-Enolase 1 (ENO1) was lower in the placentas of RM. Importantly, E2F8 can transcriptionally regulate the expression of ENO1 to promote the invasion of trophoblast cells by inhibiting secreted frizzled-related protein 1/4 (SFRP1/4) to activate Wnt signaling pathway. Our results suggest that ENO1 can promote trophoblast invasion via an E2F8-dependent manner, highlighting a potential novel target for the physiological mechanisms of RM.

Doxorubicin-based ENO1 targeted drug delivery strategy enhances therapeutic efficacy against colorectal cancer.

Alpha-enolase (ENO1), a multifunctional protein with carcinogenic properties, has emerged as a promising cancer biomarker because of its differential expression in cancer and normal cells. On the basis of this characteristic, we designed a cell-targeting peptide that specifically targets ENO1 and connected it with the drug doxorubicin (DOX) by aldehyde-amine condensation. A surface plasmon resonance (SPR) assay showed that the affinity for ENO1 was stronger (KD = 2.5 µM) for the resulting cell-targeting drug, DOX-P, than for DOX. Moreover, DOX-P exhibited acid-responsive capabilities, enabling precise release at the tumor site under the guidance of the homing peptide and alleviating DOX-induced cardiotoxicity. An efficacy experiment confirmed that, the targeting ability of DOX-P toward ENO1 demonstrated superior antitumor activity against colorectal cancer than that of DOX, while reducing its toxicity to cardiomyocytes. Furthermore, in vivo metabolic distribution results indicated low accumulation of DOX-P in nontumor sites, further validating its targeting ability. These results showed that the ENO1-targeted DOX-P peptide has great potential for application in targeted drug-delivery systems for colorectal cancer therapy.

Identification of host protein ENO1 (alpha-enolase) interacting with Cryptosporidium parvum sporozoite surface protein, Cpgp40.

BACKGROUND: Cryptosporidium parvum is an apicomplexan zoonotic parasite causing the diarrheal illness cryptosporidiosis in humans and animals. To invade the host intestinal epithelial cells, parasitic proteins expressed on the surface of sporozoites interact with host cells to facilitate the formation of parasitophorous vacuole for the parasite to reside and develop. The gp40 of C. parvum, named Cpgp40 and located on the surface of sporozoites, was proven to participate in the process of host cell invasion. METHODS: We utilized the purified Cpgp40 as a bait to obtain host cell proteins interacting with Cpgp40 through the glutathione S-transferase (GST) pull-down method. In vitro analysis, through bimolecular fluorescence complementation assay (BiFC) and coimmunoprecipitation (Co-IP), confirmed the solid interaction between Cpgp40 and ENO1. In addition, by using protein mutation and parasite infection rate analysis, it was demonstrated that ENO1 plays an important role in the C. parvum invasion of HCT-8 cells. RESULTS: To illustrate the functional activity of Cpgp40 interacting with host cells, we identified the alpha-enolase protein (ENO1) from HCT-8 cells, which showed direct interaction with Cpgp40. The mRNA level of ENO1 gene was significantly decreased at 3 and 24 h after C. parvum infection. Antibodies and siRNA specific to ENO1 showed the ability to neutralize C. parvum infection in vitro, which indicated the participation of ENO1 during the parasite invasion of HCT-8 cells. In addition, we further demonstrated that ENO1 protein was involved in the regulation of cytoplasmic matrix of HCT-8 cells during C. parvum invasion. Functional study of the protein mutation illustrated that ENO1 was also required for the endogenous development of C. parvum. CONCLUSIONS: In this study, we utilized the purified Cpgp40 as a bait to obtain host cell proteins ENO1 interacting with Cpgp40. Functional studies illustrated that the host cell protein ENO1 was involved in the regulation of tight junction and adherent junction proteins during C. parvum invasion and was required for endogenous development of C. parvum.

Glycolytic enzyme Enolase-1 regulates insulin gene expression in pancreatic ß-cell.

Enolase-1 (Eno1) plays a critical role in regulating glucose metabolism; however, its specific impact on pancreatic islet ß-cells remains elusive. This study aimed to provide a preliminary exploration of Eno1 function in pancreatic islet ß-cells. The findings revealed that the expression of ENO1 mRNA in type 2 diabetes donors was significantly increased and positively correlated with HbA1C and negatively correlated with insulin gene expression. A high level of Eno1 in human insulin-secreting rat INS-1832/13 cells with co-localization with intracellular insulin proteins was accordingly observed. Silencing of Eno1 using siRNA or inhibiting Eno1 protein activity with an Eno1 antagonist significantly reduced insulin secretion and insulin content in ß-cells, while the proinsulin/insulin content ratio remained unchanged. This reduction in ß-cells function was accompanied by a notable decrease in intracellular ATP and mitochondrial cytochrome C levels. Overall, our findings confirm that Eno1 regulates the insulin secretion process, particularly glucose metabolism and ATP production in the ß-cells. The mechanism primarily involves its influence on insulin production, suggesting that Eno1 represents a potential target for ß-cell protection and diabetes treatment.

USP21 deubiquitinates and stabilizes HSP90 and ENO1 to promote aerobic glycolysis and proliferation in cholangiocarcinoma.

Deubiquitylating enzymes (DUBs) play an essential role in targeted protein degradation and represent an emerging therapeutic paradigm in cancer. However, their therapeutic potential in cholangiocarcinoma (CCA) has not been explored. Herein, based on The Cancer Genome Atlas (TCGA) and The Gene Expression Omnibus (GEO) databases, we found that ubiquitin-specific protease 21 (USP21) was upregulated in CCA, high USP21 level was associated with poor prognosis. In vivo and in vitro, we identified USP21 as a master regulator of CCA growth and maintenance, which directly interacted with deubiquitinates and stabilized the heat shock protein 90 (HSP90) through K48-linked deubiquitination, and in turn, this stabilization increased HIF1A expression, thus upregulating key glycolytic enzyme genes ENO2, ENO3, ALDOC, ACSS2, and then promoted aerobic glycolysis, which provided energy for CCA cell proliferation. In addition, USP21 could directly stabilize alpha-Enolase 1 (ENO1) to promote aerobic glycolysis. Furthermore, increased USP21 level enhanced chemotherapy resistance to the gemcitabine-based regimen. Taken together, we identify a USP21-regulated aerobic glycolysis mechanism that involves the USP21/HSP90/HIF1A axis and USP21/ENO1 axis in CCA tumorigenesis, which could serve as a potential target for the treatment of CCA.

Interrogating l-fuconate dehydratase with tartronate and 3-hydroxypyruvate reveals subtle differences within the mandelate racemase-subgroup of the enolase superfamily.

Enzymes of the enolase superfamily share a conserved structure and a common partial reaction (i.e., metal-assisted, Brønsted base-catalyzed enol(ate) formation). The architectures of the enolization apparatus at the active sites of the mandelate racemase (MR)-subgroup members MR and l-fuconate dehydratase (FucD) are almost indistinguishable at the structural level. Tartronate and 3-hydroxypyruvate (3-HP) recognize the enolization apparatus and can be used to interrogate the active sites for differences that may not be apparent from structural data. We report a circular dichroism-based assay of FucD activity that monitors the change in ellipticity at 216 nm (Δ[Θ]S-P = 8985 ± 87 deg cm2 mol-1) accompanying the conversion of l-fuconate to 2-keto-3-deoxy-l-fuconate. Tartronate was a linear mixed-type inhibitor of FucD (Ki = 8.4 ± 0.7 mM, αKi = 63 ± 11 mM), binding 18-fold weaker than l-fuconate, compared with 2-fold weaker binding of tartronate by MR relative to mandelate. 3-HP irreversibly inactivated FucD (kinact/KI = 0.018 ± 0.002 M-1s-1) with an efficiency that was ∼4.6 × 103-fold less than that observed with MR. The inactivation arose predominantly from modifications at multiple sites and Tris-HCl, but not l-fuconate, afforded protection against inactivation. Similar to the reaction of 3-HP with MR, 3-HP modified the Brønsted base catalyst (Lys 220) at the active site of FucD, which was facilitated by the Brønsted acid catalyst His 351. Thus, the interactions of tartronate and 3-HP with MR and FucD revealed differences in binding affinity and reactivity that differentiated between the enzymes' enolization apparatuses.

Enolase of Streptococcus suis serotype 2 promotes biomolecular condensation of ribosomal protein SA for HBMECs apoptosis.

BACKGROUND: Ribosomal protein SA (RPSA) of human brain microvascular endothelial cells (HBMECs) can transfer from the cytosol to the cell surface and act as a receptor for some pathogens, including Streptococcus suis serotype 2 (SS2), a zoonotic pathogen causing meningitis in pigs and humans. We previously reported that SS2 virulence factor enolase (ENO) binds to RPSA on the cell surface of HBMECs and induces apoptosis. However, the mechanism that activates RPSA translocation to the cell surface and induces ENO-mediated HBMEC apoptosis is unclear. RESULTS: Here, we show that RPSA localization and condensation on the host cell surface depend on its internally disordered region (IDR). ENO binds to the IDR of RPSA and promotes its interaction with RPSA and vimentin (VIM), which is significantly suppressed after 1,6-Hexanediol (1,6-Hex, a widely used tool to disrupt phase separation) treatment, indicating that ENO incorporation and thus the concentration of RPSA/VIM complexes via co-condensation. Furthermore, increasing intracellular calcium ions (Ca2+) in response to SS2 infection further facilitates the liquid-like condensation of RPSA and aggravates ENO-induced HBMEC cell apoptosis. CONCLUSIONS: Together, our study provides a previously underappreciated molecular mechanism illuminating that ENO-induced RPSA condensation activates the migration of RPSA to the bacterial cell surface and stimulates SS2-infected HBMEC death and, potentially, disease progression. This study offers a fresh avenue for investigation into the mechanism by which other harmful bacteria infect hosts via cell surfaces' RPSA.

A variant in sperm-specific glycolytic enzyme enolase 4 (ENO4) causes human male infertility.

BACKGROUND: Although defects in sperm morphology and physiology lead to male infertility, in many instances, the exact disruption of molecular pathways in a given patient is often unknown. The glycolytic pathway is an essential process to supply energy in sperm cell motility. Enolase 4 (ENO4) is crucial for the glycolytic process, which provides the energy for sperm cells in motility. ENO4 is located in the sperm principal piece and is essential for the motility and organization of the sperm flagellum. In the present study, we characterized a family with asthenozoospermia and abnormal sperm morphology as a result of a variant in the enolase 4 (ENO4) gene. METHODS: Computer-assisted semen analysis, papanicolaou smear staining and scanning electron microscopy were used to examine sperm motility and morphology for semen analysis in patients. For genetic analysis, whole-exome sequencing followed by Sanger sequencing was performed. RESULTS: Two brothers in a consanguineous family were being clinically investigated for sperm motility and morphology issues. Genetic analysis by whole-exome sequencing revealed a homozygous variant [c.293A>G, p.(Lys98Arg)] in the ENO4 gene that segregated with infertility in the family, shared by affected but not controls. CONCLUSIONS: In view of the association of asthenozoospermia and abnormal sperm morphology in Eno4 knockout mice, we consider this to be the first report describing the involvement of ENO4 gene in human male infertility. We also explore the possible involvement of another variant in explaining other phenotypic features in this family.

A comprehensive study of the interactions in the B. subtilis degradosome with special emphasis on the role of the small proteins SR1P and SR7P.

Here, we employ coelution experiments and far-western blotting to identify stable interactions between the main components of the B. subtilis degradosome and the small proteins SR1P and SR7P. Our data indicate that B. subtilis has a degradosome comprising at least RNases Y and PnpA, enolase, phosphofructokinase, glycerol-3-phosphate dehydrogenase GapA, and helicase CshA that can be co-purified without cross-linking. All interactions were corroborated by far-western blotting with proteins purified from E. coli. Previously, we discovered that stress-induced SR7P binds enolase to enhance its interaction with and activity of enolase-bound RNase Y (RnY), while SR1P transcribed under gluconeogenic conditions interacts with GapA to stimulate its interaction with and the activity of RnjA (RnjA). We show that SR1P can directly bind RnjA, RnY, and PnpA independently of GapA, whereas SR7P only interacts with enolase. Northern blotting suggests that the degradation of individual RNAs in B. subtilis under gluconeogenic or stress conditions depends on either RnjA or RnY alone or on RnjA-SR1P, RnY-SR1P, or RnY-Eno. In vitro degradation assays with RnY or RnjA substrates corroborate the in vivo role of SR1P. Currently, it is unknown which substrate property is decisive for the utilization of one of the complexes.

Monoclonal enolase-1 blocking antibody ameliorates pulmonary inflammation and fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic fatal disease with limited therapeutic options. The infiltration of monocytes and fibroblasts into the injured lungs is implicated in IPF. Enolase-1 (ENO1) is a cytosolic glycolytic enzyme which could translocate onto the cell surface and act as a plasminogen receptor to facilitate cell migration via plasmin activation. Our proprietary ENO1 antibody, HL217, was screened for its specific binding to ENO1 and significant inhibition of cell migration and plasmin activation (patent: US9382331B2). METHODS: In this study, effects of HL217 were evaluated in vivo and in vitro for treating lung fibrosis. RESULTS: Elevated ENO1 expression was found in fibrotic lungs in human and in bleomycin-treated mice. In the mouse model, HL217 reduced bleomycin-induced lung fibrosis, inflammation, body weight loss, lung weight gain, TGF-ß upregulation in bronchial alveolar lavage fluid (BALF), and collagen deposition in lung. Moreover, HL217 reduced the migration of peripheral blood mononuclear cells (PBMC) and the recruitment of myeloid cells into the lungs. In vitro, HL217 significantly reduced cell-associated plasmin activation and cytokines secretion from primary human PBMC and endothelial cells. In primary human lung fibroblasts, HL217 also reduced cell migration and collagen secretion. CONCLUSIONS: These findings suggest multi-faceted roles of cell surface ENO1 and a potential therapeutic approach for pulmonary fibrosis.

Unrevealed roles of extracellular enolase­1 (ENO1) in promoting glycolysis and pro­cancer activities in multiple myeloma via hypoxia­inducible factor 1α.

The involvement of enolase­1 (ENO1), intracellularly or extracellularly, has been implicated in cancer development. Moreover, anticancer activities of an ENO1­targeting antibody has demonstrated the pathological roles of extracellular ENO1 (surface or secreted forms). However, although ENO1 was first identified as a glycolytic enzyme in the cytosol, to the best of our knowledge, extracellular ENO1 has not been implicated in glycolysis thus far. In the present study, the effects of extracellular ENO1 on glycolysis and other related pro­cancer activities were investigated in multiple myeloma (MM) cells in vitro and in vivo. Knockdown of ENO1 expression reduced lactate production, cell viability, cell migration and surface ENO1 expression in MM cells. Notably, addition of extracellular ENO1 protein in cancer cell culture enhanced glycolytic activity, hypoxia­inducible factor 1­α (HIF­1α) expression, glycolysis­related gene (GRG) expression and pro­cancer activities, such as cell migration, cell viability and tumor­promoting cytokine secretion. Consistently, these extracellular ENO1­induced cellular effects were inhibited by an ENO1­specific monoclonal antibody (mAb). In addition, extracellular ENO1­mediated glycolysis, GRG expression and pro­cancer activities were also reduced by HIF­1α silencing. Lastly, administration of an ENO1 mAb reduced tumor growth and serum lactate levels in an MM xenograft model. These results suggested that extracellular ENO1 (surface or secreted forms) enhanced a HIF­1α­mediated glycolytic pathway, in addition to its already identified roles. Therefore, the results of the present study highlighted the therapeutic potential of ENO1­specific antibodies in treating MM, possibly via glycolysis inhibition, and warrant further studies in other types of cancer.

Diclofenac sodium and dexamethasone co-therapy restores brain neuron-specific enolase (NSE), S-100 Beta and glial fibrillary acid protein (GFAP) proteins in experimental rat's model: A possible inhibition of P-glycoprotein.

Non-steroidal anti-inflammatory drugs decrease pain and fever while corticosteroids regulate inflammation and immune response, both are prescribed to reduce inflammation and control pain. The present study aimed to study the effects of their monotherapy and co-administration on the brain tissue structure of experimental rats. P-glycoprotein (PGP), a transporter membrane protein, plays an important role in various physiological and physio-pathological conditions, drug-drug and drug-food interactions, and multi-drug resistance. Male rats were divided into four groups and received normal saline, dexamethasone, diclofenac sodium and their dual therapy respectively, then after one-month rats were sacrificed and brain tissues proceeded for hematoxylin and eosin staining to study their histopathology and immunohistochemically staining of NSE, S100-B and GFAP biomarkers were performed. Additionally, in silico molecular docking studies were conducted to elucidate interactions between PGP and used compounds. Resultsshowed that dexamethasone or diclofenac sodium treatments showed abnormalities like edema, neuronal vacuoles, astrocytes hyperplasia and microglial cells with positive reaction to NSE, S100 and GFAP antibodies while the dual therapy displayed less edema and other signs of damage with negative and weak positive staining of NSE, S100 and GFAP antibodies respectively. The molecular docking showed that there were different affinities toward the involved PGP active site. These interaction results were great with Dexamethasone -9.6 kcal/mol forming hydrophobic interactions with the highest affinity when compared with Diclofenac sodium which gave -8.4 kcal/mol. In conclusion, the side effects of the two types of anti-inflammatory drugs may be minimized through their interactions. However, Molecular Dynamic Simulations studies are required to explain the exact dynamic behaviors and protein-ligand stability.

The CD4+ T cell repertoire specific for citrullinated peptides shows evidence of immune tolerance.

Rheumatoid arthritis occurs most often in people who express HLA-DR molecules containing a five aa "shared epitope" in the ß chain. These MHCII molecules preferentially bind citrullinated peptides formed by posttranslational modification of arginine. Citrullinated peptide:HLA-DR complexes may act as arthritis-initiating neo-antigens for CD4+ T cells. Here, we used fluorophore-conjugated HLA-DR tetramers containing citrullinated peptides from human cartilage intermediate layer protein, fibrinogen, vimentin, or enolase 1 to track cognate CD4+ T cells. Immunization of HLA-DR transgenic mice with citrullinated peptides from vimentin or enolase 1 failed to cause any expansion of tetramer-binding cells, whereas immunization with citrullinated peptides from cartilage intermediate layer protein or fibrinogen elicited some expansion. The expanded tetramer-binding populations, however, had lower T helper 1 and higher regulatory T cell frequencies than populations elicited by viral peptides. These results indicate that HLA-DR-bound citrullinated peptides are not neo-antigens and induce varying degrees of immune tolerance that could pose a barrier to rheumatoid arthritis.

DeSUMOylation of a Verticillium dahliae enolase facilitates virulence by derepressing the expression of the effector VdSCP8.

The soil-borne fungus Verticillium dahliae, the most notorious plant pathogen of the Verticillium genus, causes vascular wilts in a wide variety of economically important crops. The molecular mechanism of V. dahliae pathogenesis remains largely elusive. Here, we identify a small ubiquitin-like modifier (SUMO)-specific protease (VdUlpB) from V. dahliae, and find that VdUlpB facilitates V. dahliae virulence by deconjugating SUMO from V. dahliae enolase (VdEno). We identify five lysine residues (K96, K254, K259, K313 and K434) that mediate VdEno SUMOylation, and SUMOylated VdEno preferentially localized in nucleus where it functions as a transcription repressor to inhibit the expression of an effector VdSCP8. Importantly, VdUlpB mediates deSUMOylation of VdEno facilitates its cytoplasmic distribution, which allows it to function as a glycolytic enzyme. Our study reveals a sophisticated pathogenic mechanism of VdUlpB-mediated enolase deSUMOylation, which fortifies glycolytic pathway for growth and contributes to V. dahliae virulence through derepressing the expression of an effector.

Extracellular Pgk1 interacts neural membrane protein enolase-2 to improve the neurite outgrowth of motor neurons.

Understanding the molecular interaction between ligand and receptor is important for providing the basis for the development of regenerative drugs. Although it has been reported that extracellular phosphoglycerate kinase 1 (Pgk1) can promote the neurite outgrowth of motoneurons, the Pgk1-interacting neural receptor remains unknown. Here we show that neural membranous Enolase-2 exhibits strong affinity with recombinant Pgk1-Flag, which is also evidently demonstrated by immunoelectron microscopy. The 325th-417th domain of Pgk1 interacts with the 405th-431st domain of Enolase-2, but neither Enolase-1 nor Enolase-3, promoting neurite outgrowth. Combining Pgk1 incubation and Enolase-2 overexpression, we demonstrate a highly significant enhancement of neurite outgrowth of motoneurons through a reduced p-P38-T180/p-Limk1-S323/p-Cofilin signaling. Collectively, extracellular Pgk1 interacts neural membrane receptor Enolase-2 to reduce the P38/Limk1/Cofilin signaling which results in promoting neurite outgrowth. The extracellular Pgk1-specific neural receptor found in this study should provide a material for screening potential small molecule drugs that promote motor nerve regeneration.

ENO1 promotes liver carcinogenesis through YAP1-dependent arachidonic acid metabolism.

Enolase 1 (ENO1) is a glycolytic enzyme that plays essential roles in various pathological activities including cancer development. However, the mechanisms underlying ENO1-contributed tumorigenesis are not well explained. Here, we uncover that ENO1, as an RNA-binding protein, binds to the cytosine-uracil-guanine-rich elements of YAP1 messenger RNA to promote its translation. ENO1 and YAP1 positively regulate alternative arachidonic acid (AA) metabolism by inverse regulation of PLCB1 and HPGD (15-hydroxyprostaglandin dehydrogenase). The YAP1/PLCB1/HPGD axis-mediated activation of AA metabolism and subsequent accumulation of prostaglandin E2 (PGE2) are responsible for ENO1-mediated cancer progression, which can be retarded by aspirin. Finally, aberrant activation of ENO1/YAP1/PLCB1 and decreased HPGD expression in clinical hepatocellular carcinoma samples indicate a potential correlation between ENO1-regulated AA metabolism and cancer development. These findings underline a new function of ENO1 in regulating AA metabolism and tumorigenesis, suggesting a therapeutic potential for aspirin in patients with liver cancer with aberrant expression of ENO1 or YAP1.

Enolase 1 of Candida albicans binds human CD4+ T cells and modulates naïve and memory responses.

To obtain a better understanding of the biology behind life-threatening fungal infections caused by Candida albicans, we recently conducted an in silico screening for fungal and host protein interaction partners. We report here that the extracellular domain of human CD4 binds to the moonlighting protein enolase 1 (Eno1) of C. albicans as predicted bioinformatically. By using different anti-CD4 monoclonal antibodies, we determined that C. albicans Eno1 (CaEno1) primarily binds to the extracellular domain 3 of CD4. Functionally, we observed that CaEno1 binding to CD4 activated lymphocyte-specific protein tyrosine kinase (LCK), which was also the case for anti-CD4 monoclonal antibodies tested in parallel. CaEno1 binding to naïve human CD4+ T cells skewed cytokine secretion toward a Th2 profile indicative of poor fungal control. Moreover, CaEno1 inhibited human memory CD4+ T-cell recall responses. Therapeutically, CD4+ T cells transduced with a p41/Crf1-specific T-cell receptor developed for adoptive T-cell therapy were not inhibited by CaEno1 in vitro. Together, the interaction of human CD4+ T cells with CaEno1 modulated host CD4+ T-cell responses in favor of the fungus. Thus, CaEno1 mediates not only immune evasion through its interference with complement regulators but also through the direct modulation of CD4+ T-cell responses.

Keratin 17 covalently binds to alpha-enolase and exacerbates proliferation of keratinocytes in psoriasis.

Dysregulated glucose metabolism is an important characteristic of psoriasis. Cytoskeletal protein keratin 17 (K17) is highly expressed in the psoriatic epidermis and contributes to psoriasis pathogenesis. However, whether K17 is involved in the dysregulated glucose metabolism of keratinocytes (KCs) in psoriasis remains unclear. In the present study, loss- and gain-of-function studies showed that elevated K17 expression was critically involved in glycolytic pathway activation in psoriatic KCs. The level of α-enolase (ENO1), a novel potent interaction partner of K17, was also elevated in psoriatic KCs. Knockdown of ENO1 by siRNA or inhibition of ENO1 activity by the inhibitor ENOBlock remarkably suppressed KCs glycolysis and proliferation. Moreover, ENO1 directly interacted with K17 and maintained K17-Ser44 phosphorylation to promote the nuclear translocation of K17, which promoted the transcription of the key glycolysis enzyme lactic dehydrogenase A (LDHA) and resulted in enhanced KCs glycolysis and proliferation in vitro. Finally, either inhibiting the expression and activation of ENO1 or repressing K17-Ser44 phosphorylation significantly alleviated the IMQ-induced psoriasis-like phenotype in vivo. These findings provide new insights into the metabolic profile of psoriatic KCs and suggest that modulation of the ENO1-K17-LDHA axis is a potentially innovative therapeutic approach to psoriasis.