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Molecules (Basel, Switzerland) Dec 2023Dolichols are isoprenoid end-products of the mevalonate and 2-methyl-D-erythritol-4-phosphate pathways. The synthesis of dolichols is initiated with the addition of...
Dolichols are isoprenoid end-products of the mevalonate and 2-methyl-D-erythritol-4-phosphate pathways. The synthesis of dolichols is initiated with the addition of several molecules of isopentenyl diphosphate to farnesyl diphosphate. This reaction is catalyzed by a -prenyltransferase and leads to the formation of polyprenyl diphosphate. Subsequent steps involve the dephosphorylation and reduction of the α-isoprene unit by a polyprenol reductase, resulting in the generation of dolichol. The size of the dolichol varies, depending on the number of isoprene units incorporated. In eukaryotes, dolichols are synthesized as a mixture of four or more different lengths. Their biosynthesis is predicted to occur in the endoplasmic reticulum, where dolichols play an essential role in protein glycosylation. In this study, we have developed a selection of aptamers targeting dolichols and enhanced their specificity by incorporating fatty acids for negative selection. One aptamer showed high enrichment and specificity for linear polyisoprenoids containing at least one oxygen atom, such as an alcohol or aldehyde, in the α-isoprene unit. The selected aptamer proved to be a valuable tool for the subcellular localization of polyisoprenoids in the malaria parasite. To the best of our knowledge, this is the first time that polyisoprenoids have been localized within a cell using aptamer-based imaging techniques.
Topics: Animals; Parasites; Diagnostic Imaging; Dolichols; Malaria; Butadienes; Hemiterpenes
PubMed: 38202761
DOI: 10.3390/molecules29010178 -
Experimental & Molecular Medicine Feb 2024Diabetes might be associated with increased cancer risk, with several studies reporting hyperglycemia as a primary oncogenic stimulant. Since glucose metabolism is...
Diabetes might be associated with increased cancer risk, with several studies reporting hyperglycemia as a primary oncogenic stimulant. Since glucose metabolism is linked to numerous metabolic pathways, it is difficult to specify the mechanisms underlying hyperglycemia-induced cancer progression. Here, we focused on the polyol pathway, which is dramatically activated under hyperglycemia and causes diabetic complications. We investigated whether polyol pathway-derived fructose facilitates hyperglycemia-induced gastric cancer metastasis. We performed bioinformatics analysis of gastric cancer datasets and immunohistochemical analyses of gastric cancer specimens, followed by transcriptomic and proteomic analyses to evaluate phenotypic changes in gastric cancer cells. Consequently, we found a clinical association between the polyol pathway and gastric cancer progression. In gastric cancer cell lines, hyperglycemia enhanced cell migration and invasion, cytoskeletal rearrangement, and epithelial-mesenchymal transition (EMT). The hyperglycemia-induced acquisition of metastatic potential was mediated by increased fructose derived from the polyol pathway, which stimulated the nuclear ketohexokinase-A (KHK-A) signaling pathway, thereby inducing EMT by repressing the CDH1 gene. In two different xenograft models of cancer metastasis, gastric cancers overexpressing AKR1B1 were found to be highly metastatic in diabetic mice, but these effects of AKR1B1 were attenuated by KHK-A knockdown. In conclusion, hyperglycemia induces fructose formation through the polyol pathway, which in turn stimulates the KHK-A signaling pathway, driving gastric cancer metastasis by inducing EMT. Thus, the polyol and KHK-A signaling pathways could be potential therapeutic targets to decrease the metastatic risk in gastric cancer patients with diabetes.
Topics: Humans; Animals; Mice; Stomach Neoplasms; Diabetes Mellitus, Experimental; Proteomics; Signal Transduction; Hyperglycemia; Fructokinases; Fructose; Epithelial-Mesenchymal Transition; Cell Movement; Cell Line, Tumor; Aldehyde Reductase; Polymers
PubMed: 38200154
DOI: 10.1038/s12276-023-01153-3 -
Neuroscience Letters Jan 2024Hyperglycemia exacerbates ischemic brain injury by up-regulating autophagy. However, the underlying mechanisms are unknown. This study aims to determine whether...
Hyperglycemia exacerbates ischemic brain injury by up-regulating autophagy. However, the underlying mechanisms are unknown. This study aims to determine whether hyperglycemia activates autophagy through the p53-Sesn2-AMPK signaling pathway. Rats were subjected to 30-min middle cerebral artery occlusion (MCAO) with reperfusion for 1- and 3-day under normo- and hyperglycemic conditions; and HT22 cells were exposed to oxygen deprivation (OG) or oxygen-glucose deprivation and re-oxygenation (OGD/R) with high glucose. Autophagy inhibitors, 3-MA and ARI, were used both in vivo and in vitro. The results showed that, compared with the normoglycemia group (NG), hyperglycemia (HG) increased infarct volume and apoptosis in penumbra area, worsened neurological deficit, and augmented autophagy. after MCAO followed by 1-day reperfusion. Further, HG promoted the conversion of LC-3I to LC-3II, decreased p62, increased protein levels of aldose reductase, p53, P-p53, Sesn2, AMPK and numbers of autophagosomes and autolysosomes, detected by transmission electron microscopy and mRFP-GFP-LC3 molecular probe, in the cerebral cortex after ischemia and reperfusion injury in animals or in cultured HT22 cells exposed to hypoxia with high glucose content. Finally, experiments with autophagy inhibitors 3-MA and aldose reductase inhibitor (ARI) revealed that while both inhibitors reduced the number of TUNEL positive neurons and reversed the effects of hyperglycemic ischemia on LC3 and p62, only ARI decreased the levels of p53, P-p53. These results suggested that hyperglycemia might induce excessive autophagy to aggravate the brain injury resulted from I/R and that hyperglycemia might activate the p53-Sesn2-AMPK signaling pathway, in addition to the classical PI3K/AKT/mTOR autophagy pathway.
Topics: Animals; Rats; Aldehyde Reductase; AMP-Activated Protein Kinases; Autophagy; Brain Ischemia; Glucose; Hyperglycemia; Infarction, Middle Cerebral Artery; Oxygen; Phosphatidylinositol 3-Kinases; Reperfusion Injury; Signal Transduction; Tumor Suppressor Protein p53
PubMed: 38191089
DOI: 10.1016/j.neulet.2024.137629 -
PeerJ 2024Sepsis and sepsis-associated acute kidney injury (SA-AKI) pose significant global health challenges, necessitating the development of innovative therapeutic strategies....
BACKGROUND
Sepsis and sepsis-associated acute kidney injury (SA-AKI) pose significant global health challenges, necessitating the development of innovative therapeutic strategies. Dysregulated protein expression has been implicated in the initiation and progression of sepsis and SA-AKI. Identifying potential protein targets and modulating their expression is crucial for exploring alternative therapies.
METHOD
We established an SA-AKI rat model using cecum ligation perforation (CLP) and employed differential proteomic techniques to identify protein expression variations in kidney tissues. Aldose reductase (AKR1B1) emerged as a promising target. The SA-AKI rat model received treatment with the aldose reductase inhibitor (ARI), epalrestat. Blood urea nitrogen (BUN) and creatinine (CRE) levels, as well as IL-1, IL-6 and TNF- levels in the serum and kidney tissues, were monitored. Hematoxylin-eosin (H-E) staining and a pathological damage scoring scale assessed renal tissue damage, while protein blotting determined PKC (protein kinase C)/NF-B pathway protein expression.
RESULT
Differential proteomics revealed significant downregulation of seven proteins and upregulation of 17 proteins in the SA-AKI rat model renal tissues. AKR1B1 protein expression was notably elevated, confirmed by Western blot. ARI prophylactic administration and ARI treatment groups exhibited reduced renal injury, low BUN and CRE levels and decreased IL-1, IL-6 and TNF- levels compared to the CLP group. These changes were statistically significant ( < 0.05). AKR1B1, PKC-, and NF-B protein expression levels were also lowered in the ARI prophylactic administration and ARI treatment groups compared to the CLP group ( < 0.05).
CONCLUSIONS
Epalrestat appeared to inhibit the PKC/NF-B inflammatory pathway by inhibiting AKR1B1, resulting in reduced inflammatory cytokine levels in renal tissues and blood. This mitigated renal tissue injuries and improved the systemic inflammatory response in the severe sepsis rat model. Consequently, AKR1B1 holds promise as a target for treating sepsis-associated acute kidney injuries.
Topics: Animals; Rats; Acute Kidney Injury; Aldehyde Reductase; Interleukin-6; NF-kappa B; Proteomics; Sepsis; Tumor Necrosis Factor-alpha
PubMed: 38188141
DOI: 10.7717/peerj.16709 -
Chemico-biological Interactions Feb 2024Neurodegeneration is a complex process involving various inflammatory mediators and cellular responses. Aldose reductase (AR) is a key enzyme in the polyol pathway,... (Review)
Review
Neurodegeneration is a complex process involving various inflammatory mediators and cellular responses. Aldose reductase (AR) is a key enzyme in the polyol pathway, which converts glucose to sorbitol. Beyond its metabolic role, AR has also been found to play a significant role in modulating neuroinflammation. This review aims to provide an overview of the current knowledge regarding the involvement of AR inhibition in attenuating neuroinflammation and complications from diabetic neuropathies. Here, we review the literature regarding AR and neuropathy/neurodegeneration. We discuss the mechanisms underlying the influence of AR inhibitors on ocular inflammation, beta-amyloid-induced neurodegeneration, and optic nerve degeneration. Furthermore, potential therapeutic strategies targeting AR in neurodegeneration are explored. The understanding of AR's role in neurodegeneration may lead to the development of novel therapeutic interventions for other neuroinflammatory disorders.
Topics: Humans; Aldehyde Reductase; Neuroinflammatory Diseases; Diabetic Neuropathies; Enzyme Inhibitors; Inflammation
PubMed: 38185272
DOI: 10.1016/j.cbi.2024.110856 -
Archives of Toxicology Mar 2024The most important dose-limiting factor of the anthracycline idarubicin is the high risk of cardiotoxicity, in which the secondary alcohol metabolite idarubicinol plays...
In vitro evaluation of the reductive carbonyl idarubicin metabolism to evaluate inhibitors of the formation of cardiotoxic idarubicinol via carbonyl and aldo-keto reductases.
The most important dose-limiting factor of the anthracycline idarubicin is the high risk of cardiotoxicity, in which the secondary alcohol metabolite idarubicinol plays an important role. It is not yet clear which enzymes are most important for the formation of idarubicinol and which inhibitors might be suitable to suppress this metabolic step and thus would be promising concomitant drugs to reduce idarubicin-associated cardiotoxicity. We, therefore, established and validated a mass spectrometry method for intracellular quantification of idarubicin and idarubicinol and investigated idarubicinol formation in different cell lines and its inhibition by known inhibitors of the aldo-keto reductases AKR1A1, AKR1B1, and AKR1C3 and the carbonyl reductases CBR1/3. The enzyme expression pattern differed among the cell lines with dominant expression of CBR1/3 in HEK293 and MCF-7 and very high expression of AKR1C3 in HepG2 cells. In HEK293 and MCF-7 cells, menadione was the most potent inhibitor (IC = 1.6 and 9.8 µM), while in HepG2 cells, ranirestat was most potent (IC = 0.4 µM), suggesting that ranirestat is not a selective AKR1B1 inhibitor, but also an AKR1C3 inhibitor. Over-expression of AKR1C3 verified the importance of AKR1C3 for idarubicinol formation and showed that ranirestat is also a potent inhibitor of this enzyme. Taken together, our study underlines the importance of AKR1C3 and CBR1 for the reduction of idarubicin and identifies potent inhibitors of metabolic formation of the cardiotoxic idarubicinol, which should now be tested in vivo to evaluate whether such combinations can increase the cardiac safety of idarubicin therapies while preserving its efficacy.
Topics: Humans; Idarubicin; Aldo-Keto Reductases; Cardiotoxicity; HEK293 Cells; Aldehyde Reductase; Daunorubicin; Pyrazines; Spiro Compounds
PubMed: 38175295
DOI: 10.1007/s00204-023-03661-7 -
Organic Letters Jan 2024Sativene () and -sativene are an important family of fungal sesquiterpenoids that feature unique tricyclo[4.4.0.0]decane and bicyclo[3.2.1]octane skeletons,...
Sativene () and -sativene are an important family of fungal sesquiterpenoids that feature unique tricyclo[4.4.0.0]decane and bicyclo[3.2.1]octane skeletons, respectively. Herein, we identify a three-enzyme cassette: SatA cyclizes farnesyl diphosphate (FPP) to form compound ; CYP450 SatB catalyzes C14-C15 dihydroxylations and subsequent bond cleavage; and reductase SatC regioselectively reduces C14 aldehyde and mediates hemiacetal ring closure to generate prehelminthosporol (). Our findings clarify the synthetic step of sativene and its oxidative transformation processes into -sativene.
Topics: Sesquiterpenes; Oxidative Stress
PubMed: 38174895
DOI: 10.1021/acs.orglett.3c04005 -
The Journal of Biological Chemistry Feb 2024Cofactor imbalance obstructs the productivities of metabolically engineered cells. Herein, we employed a minimally perturbing system, xylose reductase and lactose...
Cofactor imbalance obstructs the productivities of metabolically engineered cells. Herein, we employed a minimally perturbing system, xylose reductase and lactose (XR/lactose), to increase the levels of a pool of sugar phosphates which are connected to the biosynthesis of NAD(P)H, FAD, FMN, and ATP in Escherichia coli. The XR/lactose system could increase the amounts of the precursors of these cofactors and was tested with three different metabolically engineered cell systems (fatty alcohol biosynthesis, bioluminescence light generation, and alkane biosynthesis) with different cofactor demands. Productivities of these cells were increased 2-4-fold by the XR/lactose system. Untargeted metabolomic analysis revealed different metabolite patterns among these cells, demonstrating that only metabolites involved in relevant cofactor biosynthesis were altered. The results were also confirmed by transcriptomic analysis. Another sugar reducing system (glucose dehydrogenase) could also be used to increase fatty alcohol production but resulted in less yield enhancement than XR. This work demonstrates that the approach of increasing cellular sugar phosphates can be a generic tool to increase in vivo cofactor generation upon cellular demand for synthetic biology.
Topics: Aldehyde Reductase; Escherichia coli; Fatty Alcohols; Fermentation; Lactose; Metabolic Engineering; Metabolic Networks and Pathways; Sugar Phosphates; Xylose
PubMed: 38159859
DOI: 10.1016/j.jbc.2023.105598 -
Plant Cell Reports Dec 2023NtTAS14-like1 enhances osmotic tolerance through coordinately activating the expression of osmotic- and ABA-related genes. Osmotic stress is one of the most important...
NtTAS14-like1 enhances osmotic tolerance through coordinately activating the expression of osmotic- and ABA-related genes. Osmotic stress is one of the most important limiting factors for tobacco (Nicotiana tabacum) growth and development. Dehydrin proteins are widely involved in plant adaptation to osmotic stress, but few of these proteins have been functionally characterized in tobacco. Here, to identify genes required for osmotic stress response in tobacco, an encoding dehydrin protein gene NtTAS14-like1 was isolated based on RNA sequence data. The expression of NtTAS14-like1 was obviously induced by mannitol and abscisic acid (ABA) treatments. Knock down of NtTAS14-like1 expression reduced osmotic tolerance, while overexpression of NtTAS14-like1 conferred tolerance to osmotic stress in transgenic tobacco plants, as determined by physiological analysis of the relative electrolyte leakage and malonaldehyde accumulation. Further expression analysis by quantitative real-time PCR indicated that NtTAS14-like1 participates in osmotic stress response possibly through coordinately activating osmotic- and ABA-related genes expression, such as late embryogenesis abundant (NtLEA5), early responsive to dehydration 10C (NtERD10C), calcium-dependent protein kinase 2 (NtCDPK2), ABA-responsive element-binding protein (NtAREB), ABA-responsive element-binding factor 1 (NtABF1), dehydration-responsive element-binding genes (NtDREB2A), xanthoxin dehydrogenase/reductase (NtABA2), ABA-aldehyde oxidase 3 (NtAAO3), 9-cis-epoxycarotenoid dioxygenase (NtNCED3). Together, this study will facilitate to improve our understandings of molecular and functional properties of plant TAS14 proteins and to improve genetic evidence on the involvement of the NtTAS14-like1 in osmotic stress response of tobacco.
Topics: Osmoregulation; Nicotiana; Dehydration; Stress, Physiological; Abscisic Acid; Plant Proteins; Plants, Genetically Modified; Osmotic Pressure; Gene Expression Regulation, Plant
PubMed: 38155260
DOI: 10.1007/s00299-023-03118-2 -
Journal of Biochemistry Mar 2024The core M3 O-mannosyl glycan on α-dystroglycan serves as the binding epitope for extracellular matrix molecules. Defects in core M3 glycans cause congenital muscular...
The core M3 O-mannosyl glycan on α-dystroglycan serves as the binding epitope for extracellular matrix molecules. Defects in core M3 glycans cause congenital muscular dystrophies that are collectively known as dystroglycanopathies. The core M3 glycan contains a tandem D-ribitol-5-phosphate (Rbo5P) structure, which is synthesized by the Rbo5P-transferases fukutin and fukutin-related protein using CDP-ribitol (CDP-Rbo) as a donor substrate. CDP-Rbo is synthesized from CTP and Rbo5P by CDP-Rbo pyrophosphorylase A. However, the Rbo5P biosynthesis pathway has yet to be elucidated in mammals. Here, we investigated the reductase activities toward four substrates, including ribose, ribulose, ribose-phosphate and ribulose-phosphate, to identify the intracellular Rbo5P production pathway and elucidated the role of the aldo-keto reductases AKR1A1, AKR1B1 and AKR1C1 in those pathways. It was shown that the ribose reduction pathway is the endogenous pathway that contributes most to Rbo5P production in HEK293T cells and that AKR1B1 is the major reductase in this pathway.
Topics: Humans; Animals; Ribitol; Ribose; Phosphates; HEK293 Cells; Dystroglycans; Oxidoreductases; Mammals; Polysaccharides; Aldehyde Reductase
PubMed: 38140954
DOI: 10.1093/jb/mvad115