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Biotechnology and Applied Biochemistry Jun 2024Clostridium aceticum DSM1496 is an acid-resistant strain in which ornithine decarboxylase (ODC) plays a crucial role in acid resistance. In this study, we expressed ODC...
Clostridium aceticum DSM1496 is an acid-resistant strain in which ornithine decarboxylase (ODC) plays a crucial role in acid resistance. In this study, we expressed ODC derived from C. aceticum DSM1496 in Escherichia coli BL21 (DE3) and thoroughly examined its enzymatic properties. The enzyme has a molecular weight of 55.27 kDa and uses pyridoxal-5'-phosphate (PLP) as a coenzyme with a K = 0.31 mM. ODC exhibits optimal activity at pH 7.5, and it maintains high stability even at pH 4.5. The peak reaction temperature for ODC is 30°C. Besides, it can be influenced by certain metal ions such as Mn. Although l-ornithine serves as the preferred substrate for ODC, the enzyme also decarboxylates l-arginine and l-lysine simultaneously. The results indicate that ODC derived from C. aceticum DSM1496 exhibits the ability to produce putrescine, cadaverine, and agmatine through decarboxylation. These polyamines have the potential to neutralize acid in an acidic environment, facilitating the growth of microorganisms. These significant findings provide a strong basis for further investigation into the acid-resistant mechanisms contributed by ODC.
Topics: Ornithine Decarboxylase; Hydrogen-Ion Concentration; Escherichia coli
PubMed: 38225812
DOI: 10.1002/bab.2556 -
Molecular Brain Jan 2024Alzheimer's disease (AD) is characterized by the loss of memory due to aggregation of misphosphorylated tau and amyloid beta (Aβ) plaques in the brain, elevated release...
Alzheimer's disease (AD) is characterized by the loss of memory due to aggregation of misphosphorylated tau and amyloid beta (Aβ) plaques in the brain, elevated release of inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and reactive oxygen species from astrocytes, and subsequent neurodegeneration. Recently, it was found that enzyme Ornithine Decarboxylase 1 (ODC1) acts as a bridge between the astrocytic urea cycle and the putrescine-to-GABA conversion pathway in the brain of AD mouse models as well as human patients. In this study, we show that the long-term knockdown of astrocytic Odc1 in APP/PS1 animals was sufficient to completely clear Aβ plaques in the hippocampus while simultaneously switching the astrocytes from a detrimental reactive state to a regenerative active state, characterized by proBDNF expression. Our experiments also reveal an effect of astrocytic ODC1 inhibition on the expression of genes involved in synapse pruning and organization, histone modification, apoptotic signaling and protein processing. These genes are previously known to be associated with astrocytic activation and together create a neuroregeneration-supportive environment in the brain. By inhibiting ODC1 for a long period of 3 months in AD mice, we demonstrate that the beneficial amyloid-clearing process of astrocytes can be completely segregated from the systemically harmful astrocytic response to insult. Our study reports an almost complete clearance of Aβ plaques by controlling an endogenous degradation process, which also modifies the astrocytic state to create a regeneration-supportive environment in the brain. These findings present the potential of modulating astrocytic clearance of Aβ as a powerful therapeutic strategy against AD.
Topics: Animals; Humans; Mice; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Astrocytes; Brain; Disease Models, Animal; gamma-Aminobutyric Acid; Mice, Transgenic; Plaque, Amyloid; Ornithine Decarboxylase
PubMed: 38216963
DOI: 10.1186/s13041-024-01076-8 -
British Journal of Cancer Mar 2024MYC genes regulate ornithine decarboxylase (Odc) to increase intratumoral polyamines. We conducted a Phase I trial [NCT02030964] to determine the maximum tolerated dose...
BACKGROUND
MYC genes regulate ornithine decarboxylase (Odc) to increase intratumoral polyamines. We conducted a Phase I trial [NCT02030964] to determine the maximum tolerated dose (MTD) of DFMO, an Odc inhibitor, with celecoxib, cyclophosphamide and topotecan.
METHODS
Patients 2-30 years of age with relapsed/refractory high-risk neuroblastoma received oral DFMO at doses up to 9000 mg/m/day, with celecoxib (500 mg/m daily), cyclophosphamide (250 mg/m/day) and topotecan (0.75 mg/m/day) IV for 5 days, for up to one year with G-CSF support.
RESULTS
Twenty-four patients (median age, 6.8 years) received 136 courses. Slow platelet recovery with 21-day courses (dose-levels 1 and 2) led to subsequent dose-levels using 28-day courses (dose-levels 2a-4a). There were three course-1 dose-limiting toxicities (DLTs; hematologic; anorexia; transaminases), and 23 serious adverse events (78% fever-related). Five patients (21%) completed 1-year of therapy. Nine stopped for PD, 2 for DLT, 8 by choice. Best overall response included two PR and four MR. Median time-to-progression was 19.8 months, and 3 patients remained progression-free at >4 years without receiving additional therapy. The MTD of DFMO with this regimen was 6750 mg/m/day.
CONCLUSION
High-dose DFMO is tolerable when added to chemotherapy in heavily pre-treated patients. A randomized Phase 2 trial of DFMO added to chemoimmunotherapy is ongoing [NCT03794349].
Topics: Child; Humans; Antineoplastic Combined Chemotherapy Protocols; Celecoxib; Cyclophosphamide; Neoplasm Recurrence, Local; Neuroblastoma; Topotecan; Child, Preschool; Adolescent; Young Adult; Adult
PubMed: 38200233
DOI: 10.1038/s41416-023-02525-2 -
Cell Communication and Signaling : CCS Jan 2024Metabolism of polyamines is of critical importance to physiological processes. Ornithine decarboxylase (ODC) antizyme inhibitors (AZINs) are capable of interacting with... (Review)
Review
Metabolism of polyamines is of critical importance to physiological processes. Ornithine decarboxylase (ODC) antizyme inhibitors (AZINs) are capable of interacting with antizymes (AZs), thereby releasing ODC from ODC-AZs complex, and promote polyamine biosynthesis. AZINs regulate reproduction, embryonic development, fibrogenesis and tumorigenesis through polyamine and other signaling pathways. Dysregulation of AZINs has involved in multiple human diseases, especially malignant tumors. Adenosine-to-inosine (A-to-I) RNA editing is the most common type of post-transcriptional nucleotide modification in humans. Additionally, the high frequencies of RNA-edited AZIN1 in human cancers correlates with increase of cancer cell proliferation, enhancement of cancer cell stemness, and promotion of tumor angiogenesis. In this review, we summarize the current knowledge on the various contribution of AZINs related with potential cancer promotion, cancer stemness, microenvironment and RNA modification, especially underlying molecular mechanisms, and furthermore explored its promising implication for cancer diagnosis and treatment.
Topics: Humans; Ornithine Decarboxylase; Translational Research, Biomedical; Polyamines; Cell Transformation, Neoplastic; RNA; Tumor Microenvironment
PubMed: 38169396
DOI: 10.1186/s12964-023-01445-1 -
Cutaneous and Ocular Toxicology Mar 2024Skin exposure to noxious agents leads to cutaneous lesion marked by an increase in inflammation, cellular proliferation, and hyperplasiogenic reactions. Studies have...
PURPOSE
Skin exposure to noxious agents leads to cutaneous lesion marked by an increase in inflammation, cellular proliferation, and hyperplasiogenic reactions. Studies have demonstrated that these damages breach the skin integrity resulting in the aetiology of various cutaneous disorders like atopic dermatitis, eczema, psoriasis, and development of non-melanoma skin cancer. Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, is an effective treatment for a variety of inflammatory diseases. Its importance in the therapy of skin problems, however, remains under appreciated.
METHODS
We tested efficacy of topically applied celecoxib in mitigating skin inflammation, cellular proliferation, and hyperplasia induced by the phorbol ester 12--tetradecanoylphorbol-13-acetate (TPA) in Swiss albino mice.
RESULTS
Celecoxib (5 and 10 μmol) markedly reduced TPA (10 nmol) induced prostaglandin E (PGE) production, oedema formation, myeloperoxidase (MPO) activity, and levels of pro-inflammatory cytokines such as tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). It also resulted in a considerable decrease in ornithine decarboxylase (ODC) activity and the incorporation of [H]-thymidine into DNA. In addition, there was a significant reduction in histoarchitectural abnormalities such as epidermal thickness, number of epidermal cell layers, neutrophil infiltration, intercellular oedema, and vasodilation.
CONCLUSION
Our results demonstrate that topical celecoxib can reduce the inflammation, hyperproliferation, and hyperplasiogenic events of skin insults suggesting that it may prove to be a valuable management option for cutaneous lesion and associated illnesses such as atopic dermatitis, eczema, and psoriasis, as well as the emergence of non-melanoma cancer.
Topics: Mice; Animals; Celecoxib; Dermatitis, Atopic; Ornithine Decarboxylase; Skin; Tetradecanoylphorbol Acetate; Inflammation; Skin Diseases; Psoriasis; Edema; Acetates; Eczema; Skin Neoplasms
PubMed: 38127818
DOI: 10.1080/15569527.2023.2295843 -
BioRxiv : the Preprint Server For... Dec 2023The eukaryotic genome, first packed into nucleosomes of about 150 bp around the histone core, is organized into euchromatin and heterochromatin, corresponding to the A...
The eukaryotic genome, first packed into nucleosomes of about 150 bp around the histone core, is organized into euchromatin and heterochromatin, corresponding to the A and B compartments, respectively. Here, we asked if individual nucleosomes in vivo know where to go. That is, do mono-nucleosomes by themselves contain A/B compartment information, associated with transcription activity, in their biophysical properties? We purified native mono-nucleosomes to high monodispersity and used physiological concentrations of biological polyamines to determine their condensability. The chromosomal regions known to partition into A compartments have low condensability and vice versa. chromatin polymer simulations using condensability as the only input showed that biophysical information needed to form compartments is all contained in single native nucleosomes and no other factors are needed. Condensability is also strongly anticorrelated with gene expression, and especially so near the promoter region and in a cell type dependent manner. Therefore, individual nucleosomes in the promoter know whether the gene is on or off, and that information is contained in their biophysical properties. Comparison with genetic and epigenetic features suggest that nucleosome condensability is a very meaningful axis onto which to project the high dimensional cellular chromatin state. Analysis of condensability using various condensing agents including those that are protein-based suggests that genome organization principle encoded into individual nucleosomes is electrostatic in nature. Polyamine depletion in mouse T cells, by either knocking out ornithine decarboxylase (ODC) or inhibiting ODC, results in hyperpolarized condensability, suggesting that when cells cannot rely on polyamines to translate biophysical properties of nucleosomes to control gene expression and 3D genome organization, they accentuate condensability contrast, which may explain dysfunction known to occur with polyamine deficiency.
PubMed: 38106048
DOI: 10.1101/2023.12.08.570828 -
Journal of Insect Physiology Jan 2024The brown planthopper (BPH, Nilaparvata lugens), a major insect pest of rice, can make a shift in wing dimorphism to adapt to complex external environments. Our previous...
The brown planthopper (BPH, Nilaparvata lugens), a major insect pest of rice, can make a shift in wing dimorphism to adapt to complex external environments. Our previous study showed that NlODC (Ornithine decarboxylase in N. lugens) was involved in wing dimorphism of the brown planthopper. Here, further experiments were conducted to reveal possible molecular mechanism of NlODC in manipulating the wing dimorphism. We found that the long-winged rate (LWR) of BPH was significantly reduced after RNAi of NlODC or injection of DFMO (D, L-α-Difluoromethylornithine), and LWR of males and females significantly decreased by 21.7% and 34.6%, respectively. Meanwhile, we also examined the contents of three polyamines under DFMO treatment and found that the contents of putrescine and spermidine were significantly lower compared to the control. After 3rd instar nymphs were injected with putrescine and spermidine, LWR was increased significantly in both cases, and putrescine was a little bit more effective, with 5.6% increase in males and 11.4% in females. Three days after injection of dsNlODC, injection of putrescine and spermidine rescued LWR to the normal levels. In the regulation of wing differentiation in BPH, NlODC mutually antagonistic to NlAkt may act through other signaling pathways rather than the classical insulin signaling pathway. This study illuminated a physiological function of an ODC gene involved in wing differentiation in insects, which could be a potential target for pest control.
Topics: Female; Male; Animals; Ornithine Decarboxylase; Hemiptera; Sex Characteristics; Putrescine; Spermidine
PubMed: 38043786
DOI: 10.1016/j.jinsphys.2023.104587 -
BioRxiv : the Preprint Server For... Nov 2023The glioblastoma microenvironment is enriched in immunosuppressive factors that potently interfere with the function of cytotoxic T lymphocytes. Cancer cells can...
The glioblastoma microenvironment is enriched in immunosuppressive factors that potently interfere with the function of cytotoxic T lymphocytes. Cancer cells can directly impact the immune system, but the mechanisms driving these interactions are not completely clear. Here we demonstrate that the polyamine metabolite spermidine is elevated in the glioblastoma tumor microenvironment. Exogenous administration of spermidine drives tumor aggressiveness in an immune-dependent manner in pre-clinical mouse models via reduction of CD8+ T cell frequency and phenotype. Knockdown of ornithine decarboxylase, the rate-limiting enzyme in spermidine synthesis, did not impact cancer cell growth in vitro but did result in extended survival. Furthermore, glioblastoma patients with a more favorable outcome had a significant reduction in spermidine compared to patients with a poor prognosis. Our results demonstrate that spermidine functions as a cancer cell-derived metabolite that drives tumor progression by reducing CD8+T cell number and function.
PubMed: 38014234
DOI: 10.1101/2023.11.14.567048 -
Analytica Chimica Acta Dec 2023Escherichia coli and Shigella spp. are closely related, making it crucial to accurately identify them for disease control and prevention. In this study, we utilized...
Escherichia coli and Shigella spp. are closely related, making it crucial to accurately identify them for disease control and prevention. In this study, we utilized MALDI-TOF MS to identify characteristic peaks of decarboxylation products of lysine and ornithine to distinguish between E. coli and Shigella spp. Our findings indicate that the peak at m/z 103.12 ± 0.1 of the product cadaverine from lysine decarboxylase is unique to E. coli, while all Shigella species lack the m/z 103.12 ± 0.1 peak. However, S. sonnei and S. boydii serotype C13 exhibit a specific peak at m/z 89.10 ± 0.1, which is the product of putrescine from ornithine decarboxylase. We were able to correctly identify 97.06% (132 of 136) of E. coli and Shigella isolates and 100% (8 of 8) of S. sonnei isolates using this biochemical-based MALDI-TOF MS detection system. This technology is advantageous for its high-throughput, high quality, and ease of operation, and is of significant value for the diagnosis of E. coli and Shigella-related diseases.
Topics: Escherichia coli; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Shigella; Cadaverine; Putrescine
PubMed: 37996154
DOI: 10.1016/j.aca.2023.341967 -
Journal of Plant Physiology Dec 2023Drought stress is a major factor limiting agricultural development, and exogenous polyamines (PAs) can increase plant drought resistance by enhancing antioxidant...
Enriched endogenous free Spd and Spm in alfalfa (Medicago sativa L.) under drought stress enhance drought tolerance by inhibiting HO production to increase antioxidant enzyme activity.
Drought stress is a major factor limiting agricultural development, and exogenous polyamines (PAs) can increase plant drought resistance by enhancing antioxidant activity, but few studies have examined whether endogenous PAs enhance the plant antioxidant system. Here, to investigate the effects of endogenous PAs on the antioxidant system of alfalfa under drought stress and the underlying mechanisms, two alfalfa cultivars, Longzhong (drought resistant) and Gannong No. 3 (drought sensitive), were used as test materials, and their seedlings were treated with polyethylene glycol (PEG-6000) for 8 days at -1.2 MPa to simulate drought stress. The levels of free PAs [putrescine (Put), spermidine (Spd) and spermine (Spm)], hydrogen peroxide (HO), malondialdehyde (MDA), key PA metabolism enzyme [arginine decarboxylase (ADC), ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), polyamine oxidase (PAO), and diamine oxidase (DAO)] activities, and antioxidant enzyme [superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)] activities were measured. These physiological indicators were used for correlation analysis to investigate the relationship between PA metabolism and the antioxidant enzyme system. The results showed that PA synthesis in alfalfa under drought stress was dominated by the ADC pathway. Spd and Spm played an important role in improving drought tolerance. The high levels of ADC and SAMDC activities were facilitated by the conversion of Put to Spd and Spm. HO generation by oxidative decomposition of PAs was mainly dependent on the oxidative decomposition of DAO but not PAO. Low DAO activity favored low HO production. Spd, Spm, ADC, ODC and SAMDC were positively correlated with the antioxidant enzymes SOD, CAT and POD in both cultivars under drought. Therefore, we concluded that high ADC and SAMDC activities in alfalfa promoted the conversion of Put to Spd and Spm, leading to high accumulation of Spd and Spm and low Put accumulation. Low Put levels led to low HO production through low DAO activity, and low HO levels induced the expression of antioxidant enzyme-encoding genes to improve antioxidant enzyme activity and reduce MDA accumulation and thereby enhanced drought resistance in alfalfa.
Topics: Spermidine; Spermine; Antioxidants; Hydrogen Peroxide; Medicago sativa; Droughts; Drought Resistance; Polyamines; Putrescine; Superoxide Dismutase; Peroxidases
PubMed: 37988872
DOI: 10.1016/j.jplph.2023.154139