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Mycoplasma hyopneumoniae is an important respiratory pathogen that causes great economic losses to the pig industry worldwide. Although some putative virulence factors have been reported, pathogenesis remains poorly understood. Herein, we evaluated the relative abundance of proteins in virulent 168 (F107) and attenuated 168L (F380) M. hyopneumoniae strains to identify virulence-associated factors by two-dimensional electrophoresis (2-DE). Seven proteins were found to be ≥ 1.5-fold more abundant in 168, and protein–protein interaction network analysis revealed that all seven interact with putative virulence factors. Unexpectedly, six of these virulence-associated proteins are encoded by core rather than accessory genomic elements. The most differentially abundant of the seven, fructose-1,6-bisphosphate aldolase (FBA), was successfully cloned, expressed and purified. Flow cytometry demonstrated the surface localisation of FBA, recombinant FBA (rFBA) mediated adhesion to swine tracheal epithelial cells (STEC), and anti-rFBA sera decreased adherence to STEC. Surface plasmon resonance showed that rFBA bound to fibronectin with a moderately strong K D of 469 nM. The results demonstrate that core gene expression contributes to adhesion and virulence in M. hyopneumoniae , and FBA moonlights as an important adhesin, mediating binding to host cells via fibronectin.

Cancer, a complicated disease characterized by aberrant cellular metabolism, has emerged as a formidable global health challenge. Since the discovery of abnormal aldolase A (ALDOA) expression in liver cancer for the first time, its overexpression has been identified in numerous cancers, including colorectal cancer (CRC), breast cancer (BC), cervical adenocarcinoma (CAC), non-small cell lung cancer (NSCLC), gastric cancer (GC), hepatocellular carcinoma (HCC), pancreatic cancer adenocarcinoma (PDAC), and clear cell renal cell carcinoma (ccRCC). Moreover, ALDOA overexpression promotes cancer cell proliferation, invasion, migration, and drug resistance, and is closely related to poor prognosis of patients with cancer. Although originally discovered to promote cancer initiation and progression by accelerating glycolysis, recent studies have revealed its atypical roles in cancer, e.g., adjusting cytoskeleton, regulating mRNA translation, cell signaling pathways, and DNA repair. These aforementioned findings challenge our traditional understanding of ALDOA function and prompt deep exploration of its novel roles in tumor biology. The present review summarizes the latest insights into ALDOA as a potential cancer biomarker and therapeutic target.

The melanoma‐microglia cross‐talk upregulates the expression of aldolase C (ALDOC) in melanoma cells from several patients. The response of melanoma cells from 2 different patients to ALDOC upregulation was diametrically divergent. Whereas several metastasis‐associated functions including brain metastasis formation were augmented in one melanoma cell line (Mel 1), these functions were attenuated in the other melanoma cell line (Mel 2). Previous studies indicated that microglia cells upregulate the expression of aldolase C (ALDOC) in melanoma cells. The present study using brain‐metastasizing variants from three human melanomas explores the functional role of ALDOC in the formation and maintenance of melanoma brain metastasis (MBM). ALDOC overexpression impacted differentially the malignant phenotype of these three variants. In the first variant, ALDOC overexpression promoted cell viability, adhesion to and transmigration through a layer of brain endothelial cells, and amplified brain micrometastasis formation. The cross‐talk between this MBM variant and microglia cells promoted the proliferation and migration of the latter cells. In sharp contrast, ALDOC overexpression in the second brain‐metastasizing melanoma variant reduced or did not affect the same malignancy features. In the third melanoma variant, ALDOC overexpression augmented certain characteristics of malignancy and reduced others. The analysis of biological functions and disease pathways in the ALDOC overexpressing variants clearly indicated that ALDOC induced the expression of tumor progression promoting genes in the first variant and antitumor progression properties in the second variant. Overall, these results accentuate the complex microenvironment interactions between microglia cells and MBM, and the functional impact of intertumor heterogeneity. Since intertumor heterogeneity imposes a challenge in the planning of cancer treatment, we propose to employ the functional response of tumors with an identical histology, to a particular drug or the molecular signature of this response, as a predictive indicator of response/nonresponse to this drug.

Sperm mobility is defined as sperm movement against resistance at body temperature. Although all mobile sperm are motile, not all motile sperm are mobile. Sperm mobility is a primary determinant of male fertility in the chicken. Previous work explained phenotypic variation at the level of the sperm cell and the mitochondrion. The present work was conducted to determine if phenotypic variation could be explained at the level of the proteome using semen donors from lines of chickens selected for low or high sperm mobility. We began by testing the hypothesis that premature mitochondrial failure, and hence sperm immobility, arose from Ca²⁺ overloading. The hypothesis was rejected because staining with a cell permeant Ca²⁺-specific dye was not enhanced in the case of low mobility sperm. The likelihood that sperm require little energy before ejaculation and the realization that the mitochondrial permeability transition can be induced by oxidative stress arising from inadequate NADH led to the hypothesis that glycolytic enzymes might differ between lines. This possibility was confirmed by 2-dimensional electrophoresis for aldolase and phosphoglycerate kinase 1. This outcome warranted evaluation of the whole cell proteome by differential detergent fractionation and mass spectrometry. Bioinformatics evaluation of proteins with different expression levels confirmed the likelihood that ATP metabolism and glycolysis differ between lines. This experimental outcome corroborated differences observed between lines in previous work, which include mitochondrial ultrastructure, sperm cell oxygen consumption, and straight line velocity. Although glycolytic proteins were more abundant within highly mobile sperm, quantitative PCR of representative testis RNA, which included mRNA for phosphoglycerate kinase 1, found no difference between lines. In summary, we propose a proteome-based model for sperm mobility phenotype in which a genetic predisposition puts sperm cells at risk of premature mitochondrial failure as they pass through the excurrent ducts of the testis. In other words, we attribute mitochondrial failure to sperm cell and reproductive tract attributes that interact to affect sperm in a stochastic manner before ejaculation. In conclusion, our work provides a starting point for understanding chicken semen quality in terms of gene networks.

Fructose-bisphophate aldolase (FbaB), is an enzyme in glycolysis and gluconeogenesis in living organisms. The mutagenesis in a unique fbaB gene of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak, led the pathogen not only unable to use pyruvate and malate for growth and delayed its growth when fructose was used as the sole carbon source, but also reduced extracellular polysaccharide (EPS) production and impaired bacterial virulence and growth in rice. Intriguingly, the fbaB promoter contains an imperfect PIP-box (plant-inducible promoter) (TTCGT-N(9)-TTCGT). The expression of fbaB was negatively regulated by a key hrp regulatory HrpG and HrpX cascade. Base substitution in the PIP-box altered the regulation of fbaB with the cascade. Furthermore, the expression of fbaB in X. oryzae pv. oryzicola RS105 strain was inducible in planta rather than in a nutrient-rich medium. Except other hrp-hrc-hpa genes, the expression of hrpG and hrpX was repressed and the transcripts of hrcC, hrpE and hpa3 were enhanced when fbaB was deleted. The mutation in hrcC, hrpE or hpa3 reduced the ability of the pathogen to acquire pyruvate and malate. In addition, bacterial virulence and growth in planta and EPS production in RΔfbaB mutant were completely restored to the wild-type level by the presence of fbaB in trans. This is the first report to demonstrate that carbohydrates, assimilated by X. oryzae pv. oryzicola, play critical roles in coordinating hrp gene expression through a yet unknown regulator.

Loss of hepatic fructose-1, 6-bisphosphate aldolase B (Aldob) leads to a paradoxical up-regulation of glucose metabolism to favor hepatocellular carcinogenesis (HCC), but the upstream signaling events remain poorly defined. Akt is highly activated in HCC, and targeting Akt is being explored as a potential therapy for HCC. Herein, we demonstrate that Aldob suppresses Akt activity and tumor growth through a protein complex containing Aldob, Akt, and protein phosphatase 2A (PP2A), leading to inhibition of cell viability, cell cycle progression, glucose uptake, and metabolism. Interestingly, Aldob directly interacts with phosphorylated Akt (p-Akt) and promotes the recruitment of PP2A to dephosphorylate p-Akt, and this scaffolding effect of Aldob is independent of its enzymatic activity. Loss of Aldob or disruption of Aldob/Akt interaction in Aldob R304A mutant restores Akt activity and tumor-promoting effects. Consistently, Aldob and p-Akt expression are inversely correlated in human HCC tissues, and Aldob down-regulation coupled with p-Akt up-regulation predicts a poor prognosis for HCC. We have further discovered that Akt inhibition or a specific small-molecule activator of PP2A (SMAP) efficiently attenuates HCC tumorigenesis in xenograft mouse models. Our work reveals a novel nonenzymatic role of Aldob in negative regulation of Akt activation, suggesting that directly inhibiting Akt activity or through reactivating PP2A may be a potential therapeutic approach for HCC treatment.

Gliding motility and host-cell invasion by apicomplexan parasites depend on cell-surface adhesins that are translocated via an actin–myosin motor beneath the membrane. The current model posits that fructose-1,6-bisphosphate aldolase (ALD) provides a critical link between the cytoplasmic tails of transmembrane adhesins and the actin–myosin motor. Here we tested this model using the Toxoplasma gondii apical membrane protein 1 (TgAMA1), which binds to aldolase in vitro. TgAMA1 cytoplasmic tail mutations that disrupt ALD binding in vitro showed no correlation with host-cell invasion, indicating this interaction is not essential. Furthermore, ALD-depleted parasites were impaired when grown in glucose, yet they showed normal gliding and invasion in glucose-free medium. Depletion of ALD in the presence of glucose led to accumulation of fructose-1,6-bisphosphate, which has been associated with toxicity in other systems. Finally, TgALD knockout parasites and an ALD mutant that specifically disrupts adhesin binding in vitro also supported normal invasion when cultured in glucose-free medium. Taken together, these results suggest that ALD is primarily important for energy metabolism rather than interacting with microneme adhesins, challenging the current model for apicomplexan motility and invasion.

The lactating mammary gland strongly induces de novo lipogenesis (DNL) to support the synthesis of fatty acids, triglycerides, and cholesterol found within milk. In monogastric species, glucose is a major substrate utilized for DNL within the lactating mammary gland and must be efficiently taken up and processed to supply cytosolic acetyl-CoA for DNL. Along with the enzymes of the DNL pathway, the glycolytic enzyme, Aldolase C ( Aldoc ), is transcriptionally upregulated and is highly expressed during lactation in the mammary gland, suggesting a role for Aldoc in lactation. Aldoc is also a transcriptional target of the sterol regulatory element binding proteins 1 and 2 (Srebp1 and Srebp2), which transcriptionally regulate enzymes within the DNL pathway and has recently been shown to regulate plasma cholesterol and triglycerides. Here, we investigate the role of Aldoc in lactation, by utilizing a whole-body Aldoc knockout mouse. Our results demonstrate that Aldoc has a significant impact on lactation, whereby pups nursing from Aldoc -/- dams have reduced body weight. Biochemical analysis of milk identified that milk from Aldoc -/- dams have significantly higher galactose, lower lactose, and cholesterol content. Mass spectrometry analysis of milk lipids from Aldoc -/- dams revealed significantly lower quantities of medium and long chain fatty acid containing triglycerides, which has direct implications on lactation as these are the predominant triglycerides synthesized from glucose in human mammary gland. Overall, our results provide functional evidence for the contribution of Aldoc in mammary gland lactose and lipid synthesis during lactation.

BackgroundHypoxia is an important factor in malignant tumors, and glycolysis is a major metabolic contributor in their development. Glycolytic enzymes have gained increasing attention as potential therapeutic targets because they are associated with cancer-specific metabolism. Fructose-bisphosphate aldolase A (ALDOA), a key glycolytic enzyme, reportedly is associated with hepatocellular carcinoma (HCC). However, its role in pathogenesis and its clinical significance in HCC remain largely unknown.AimTo explore the increased expression of ALDOA in HCC in correlation with tumor malignancy, and to investigate the potential regulatory role ALDOA plays in HCC progression through its regulation in hypoxia adaptation.Methods and ResultsTo better understand ALDOA and its correlation with clinicopathological features of HCC, we analyzed 100 HCC clinical specimens using immunohistochemistry analysis. The results show that the ALDOA expression level is significantly higher in advanced HCC and in HCC with venous invasion. Using in vitro knockdown assays, we showed that higher ALDOA expression was positively associated with cell proliferation, cell cycle, apoptosis, and invasion under both normoxic and hypoxic conditions. Evidence shows that the underlying mechanism is due to the regulatory function of ALDOA in glycolysis, the cell cycle, matrix metalloproteinase-mediated extracellular matrix degradation, and epithelial–mesenchymal transformation.ConclusionsData indicated that ALDOA is significantly upregulated in HCC tissue and is closely related to HCC malignancy. ALDOA is likely to regulate HCC progression by regulating HCC tumor cell proliferation, apoptosis, and invasion in both normoxic and hypoxic condition.

Aldolase C (Aldoc, also known as \"zebrin II\"), a brain type isozyme of a glycolysis enzyme, is expressed heterogeneously in subpopulations of cerebellar Purkinje cells (PCs) that are arranged longitudinally in a complex striped pattern in the cerebellar cortex, a pattern which is closely related to the topography of input and output axonal projections. Here, we generated knock-in Aldoc-Venus mice in which Aldoc expression is visualized by expression of a fluorescent protein, Venus. Since there was no obvious phenotypes in general brain morphology and in the striped pattern of the cerebellum in mutants, we made detailed observation of Aldoc expression pattern in the nervous system by using Venus expression in Aldoc-Venus heterozygotes. High levels of Venus expression were observed in cerebellar PCs, cartwheel cells in the dorsal cochlear nucleus, sensory epithelium of the inner ear and in all major types of retinal cells, while moderate levels of Venus expression were observed in astrocytes and satellite cells in the dorsal root ganglion. The striped arrangement of PCs that express Venus to different degrees was carefully traced with serial section alignment analysis and mapped on the unfolded scheme of the entire cerebellar cortex to re-identify all individual Aldoc stripes. A longitudinally striped boundary of Aldoc expression was first identified in the mouse flocculus, and was correlated with the climbing fiber projection pattern and expression of another compartmental marker molecule, heat shock protein 25 (HSP25). As in the rat, the cerebellar nuclei were divided into the rostrodorsal negative and the caudoventral positive portions by distinct projections of Aldoc-positive and negative PC axons in the mouse. Identification of the cerebellar Aldoc stripes in this study, as indicated in sample coronal and horizontal sections as well as in sample surface photos of whole-mount preparations, can be referred to in future experiments.