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Journal of Nippon Medical School =... 2023Dentin matrix protein 1 (DMP1) is central to matrix mineralization. Clarification of the function of DMP1 is crucial to understanding normal bone formation and...
BACKGROUND
Dentin matrix protein 1 (DMP1) is central to matrix mineralization. Clarification of the function of DMP1 is crucial to understanding normal bone formation and pathological calcification. The tissue-nonspecific alkaline phosphatase (TNAP) -progressive ankylosing enzyme (ANK) -extracellular nucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1) axis induces deposition of hydroxyapatite (HA) and pyrophosphate dehydrate (CPPD) by regulating pyrophosphate (PPi). Here, we investigated the mechanism by which DMP1 and the TNAP-ANK-ENPP1 axis participate in mineralization.
METHODS
Expression of DMP1, TNAP, NPP1, and ANK genes in MC3T3-E1 cells was detected by RT-qPCR before and after treatment with DMP1 siRNA. An enzyme-linked immunosorbent assay was used to determine expression of DMP1 protein, TNAP activity was detected by SIGMAFAST p-nitrophenyl phosphate tablets, and mineralization of osteoblasts was determined by alizarin red staining. PPi levels were determined radiometrically and equalized for cell DNA. Levels of calcium, inorganic phosphate, zinc, and magnesium were assessed by standard laboratory techniques.
RESULTS
After DMP1 gene silencing, expressions of TNAP, ENPP1, and ANK were correspondingly reduced. DMP1 altered extravesicular and intravesicular ion levels through the TNAP-ENPP1-ANK axis in MC3T3-E1 cells.
CONCLUSIONS
DMP1 regulated mineralization of MC3T3-E1 cells via the TNAP-ANK-ENPP1 axis and affected TNAP activity by two processes-rapid regulation of the Zn transporter (ZnT) and transcriptional regulation of hysteresis. However, DMP1 may affect expression of ENPP1 and ANK only via hysteresis transcriptional regulation. DMP1, as a calcium trap or catalytic enzyme, appears to have a role in collagen mineralization.
Topics: Humans; Alkaline Phosphatase; Diphosphates; Phosphoric Diester Hydrolases; Calcium; Dentin
PubMed: 37380477
DOI: 10.1272/jnms.JNMS.2023_90-306 -
Journal of Orthopaedic Surgery and... Jun 2023The deficiency of ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1) causes the phenotype similar to knee osteoarthritis (OA). However, the molecular mechanism...
OBJECTIVE AND BACKGROUND
The deficiency of ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1) causes the phenotype similar to knee osteoarthritis (OA). However, the molecular mechanism is poorly understood.
METHOD
The global deletion of Enpp1 (Enpp1) mice was created to analyze the role of Enpp1 in the progress of knee OA. The apoptosis, proliferation and chondrogenic differentiation ability of chondrocytes from wild-type (WT) and Enpp1 joints were compared. According to the results of high-throughput quantitative molecular measurements, the proteins of chondrocytes from WT and Enpp1 mice were used to explore the mechanism of Enpp1 deficiency-associated knee OA.
RESULT
In Enpp1 knee joints, we found significant chondrocyte apoptosis and proteomic results showed that abnormal expression of AMP-activated protein kinase (AMPK) signaling pathway may contribute to this phenotype. In primary chondrocyte cultures in vitro, Enpp1 deletion dramatically enhancing chondrocyte apoptosis. Meanwhile, we found Enpp1 deletion inhibits the phosphorylation of AMPK (P-AMPK). We also found that decreased level of P-AMPK and chondrocyte apoptosis, which are caused by Enpp1 deficiency, can be reversed by Acadesine (AICAR), the activator of AMPK.
CONCLUSION
Consequently, Enpp1 deficiency plays an essential role in knee OA by regulating AMPK signaling pathway.
Topics: Animals; Mice; AMP-Activated Protein Kinases; Apoptosis; Chondrocytes; Osteoarthritis, Knee; Phosphoric Diester Hydrolases; Proteomics; Pyrophosphatases; Signal Transduction
PubMed: 37370114
DOI: 10.1186/s13018-023-03923-1 -
The Plant Cell Sep 2023
Topics: Pollen Tube; Pyrus; Inorganic Pyrophosphatase; Acetylation; Pollen
PubMed: 37352196
DOI: 10.1093/plcell/koad185 -
Cureus Jun 2023Homogenates of brain tissue from the frontal cortex at autopsy in patients with amyotrophic lateral sclerosis (ALS) showed dramatically reduced levels of the enzyme...
Homogenates of brain tissue from the frontal cortex at autopsy in patients with amyotrophic lateral sclerosis (ALS) showed dramatically reduced levels of the enzyme thiamine pyrophosphatase (TPPase), the enzyme responsible for the conversion of thiamine pyrophosphate (TPP) to thiamine monophosphate (TMP). Additionally, free thiamine (vitamin B1) and TMP levels have been shown to be significantly reduced in the plasma and cerebral spinal fluid (CSF) of patients with ALS. These findings suggest that there is impaired thiamine metabolism in patients with ALS. Impaired thiamine metabolism decreases adenosine triphosphate (ATP) production and is a well-established cause of neurodegeneration. Decreased levels of TPPase, resulting in decreased levels of TMP in the cells of the frontal cortex, might account for the focal neurodegenerative changes observed in motor neurons in ALS. Benfotiamine, a safe, lipid-soluble, highly absorbable thiamine analogue, significantly raises free thiamine, TMP, and TPP levels in the blood. A case in which benfotiamine may have positively impacted the symptoms of a patient with ALS is presented. The use of benfotiamine in patients with ALS appears to be a promising therapeutic option. Considering the severity and the lack of satisfactory treatment options associated with this disease, more research on the effects of benfotiamine on the course of ALS is urgently needed.
PubMed: 37333039
DOI: 10.7759/cureus.40511 -
The Plant Cell Sep 2023Self-incompatibility (SI) is a widespread genetically determined system in flowering plants that prevents self-fertilization to promote gene flow and limit inbreeding....
Self-incompatibility (SI) is a widespread genetically determined system in flowering plants that prevents self-fertilization to promote gene flow and limit inbreeding. S-RNase-based SI is characterized by the arrest of pollen tube growth through the pistil. Arrested pollen tubes show disrupted polarized growth and swollen tips, but the underlying molecular mechanism is largely unknown. Here, we demonstrate that the swelling at the tips of incompatible pollen tubes in pear (Pyrus bretschneideri [Pbr]) is mediated by the SI-induced acetylation of the soluble inorganic pyrophosphatase (PPA) PbrPPA5. Acetylation at Lys-42 of PbrPPA5 by the acetyltransferase GCN5-related N-acetyltransferase 1 (GNAT1) drives accumulation of PbrPPA5 in the nucleus, where it binds to the transcription factor PbrbZIP77, forming a transcriptional repression complex that inhibits the expression of the pectin methylesterase (PME) gene PbrPME44. The function of PbrPPA5 as a transcriptional repressor does not require its PPA activity. Downregulating PbrPME44 resulted in increased levels of methyl-esterified pectins in growing pollen tubes, leading to swelling at their tips. These observations suggest a mechanism for PbrPPA5-driven swelling at the tips of pollen tubes during the SI response. The targets of PbrPPA5 include genes encoding cell wall-modifying enzymes, which are essential for building a continuous sustainable mechanical structure for pollen tube growth.
Topics: Pollen Tube; Ribonucleases; Inorganic Pyrophosphatase; Acetylation; Pyrus
PubMed: 37306489
DOI: 10.1093/plcell/koad162 -
Biochimica Et Biophysica Acta. General... Sep 2023Recent findings have substantially broadened our knowledge about the diversity of modifications of the 5'end of RNAs, an issue generally attributed to mRNA cap structure...
Recent findings have substantially broadened our knowledge about the diversity of modifications of the 5'end of RNAs, an issue generally attributed to mRNA cap structure (mGpppN). Nudt12 is one of the recently described new enzymatic activities involved in cap metabolism. However, in contrast to its roles in metabolite-cap turnover (e.g., NAD-cap) and NADH/NAD metabolite hydrolysis, little is known regarding its hydrolytic activity towards dinucleotide cap structures. In order to gain further insight into this Nudt12 activity, comprehensive analysis with a spectrum of cap-like dinucleotides was performed with respect to different nucleotide types adjacent to the (m)G moiety and its methylation status. Among the tested compounds, GpppA, GpppA, and GpppmA were identified as novel potent Nudt12 substrates, with K values in the same range as that of NADH. Interestingly, substrate inhibition of Nudt12 catalytic activity was detected in the case of the GpppG dinucleotide, a phenomenon not reported to date. Finally, comparison of Nudt12 with DcpS and Nud16, two other enzymes with known activity on dinucleotide cap structures, revealed their overlapping and more specific substrates. Altogether, these findings provide a basis for clarifying the role of Nudt12 in cap-like dinucleotide turnover.
Topics: NAD; Pyrophosphatases; RNA, Messenger; Hydrolysis; RNA Caps
PubMed: 37301333
DOI: 10.1016/j.bbagen.2023.130400 -
PloS One 2023Understanding metabolism in the pathogen Candida glabrata is key to identifying new targets for antifungals. The thiamine biosynthetic (THI) pathway is partially...
Understanding metabolism in the pathogen Candida glabrata is key to identifying new targets for antifungals. The thiamine biosynthetic (THI) pathway is partially defective in C. glabrata, but the transcription factor CgPdc2 upregulates some thiamine biosynthetic and transport genes. One of these genes encodes a recently evolved thiamine pyrophosphatase (CgPMU3) that is critical for accessing external thiamine. Here, we demonstrate that CgPdc2 primarily regulates THI genes. In Saccharomyces cerevisiae, Pdc2 regulates both THI and pyruvate decarboxylase (PDC) genes, with PDC proteins being a major thiamine sink. Deletion of PDC2 is lethal in S. cerevisiae in standard growth conditions, but not in C. glabrata. We uncover cryptic cis elements in C. glabrata PDC promoters that still allow for regulation by ScPdc2, even when that regulation is not apparent in C. glabrata. C. glabrata lacks Thi2, and it is likely that inclusion of Thi2 into transcriptional regulation in S. cerevisiae allows for a more complex regulation pattern and regulation of THI and PDC genes. We present evidence that Pdc2 functions independent of Thi2 and Thi3 in both species. The C-terminal activation domain of Pdc2 is intrinsically disordered and critical for species differences. Truncation of the disordered domains leads to a gradual loss of activity. Through a series of cross species complementation assays of transcription, we suggest that there are multiple Pdc2-containing complexes, and C. glabrata appears to have the simplest requirement set for THI genes, except for CgPMU3. CgPMU3 has different cis requirements, but still requires Pdc2 and Thi3 to be upregulated by thiamine starvation. We identify the minimal region sufficient for thiamine regulation in CgTHI20, CgPMU3, and ScPDC5 promoters. Defining the cis and trans requirements for THI promoters should lead to an understanding of how to interrupt their upregulation and provide targets in metabolism for antifungals.
Topics: Saccharomyces cerevisiae; Candida glabrata; Transcription Factors; Fungal Proteins; Pyruvate Decarboxylase; Thiamine; Carboxy-Lyases; Promoter Regions, Genetic; Intrinsically Disordered Proteins; Gene Expression Regulation, Fungal
PubMed: 37285346
DOI: 10.1371/journal.pone.0286744 -
European Journal of Pediatrics Aug 2023We report the long way to the correct diagnosis in two teenage sisters who developed a cardiac arrest after consuming minimal amounts of alcohol. The older girl...
We report the long way to the correct diagnosis in two teenage sisters who developed a cardiac arrest after consuming minimal amounts of alcohol. The older girl dramatically survived two cardiac arrests at the age of 14 and 15 years. She underwent an extensive examination that revealed isolated cardiac abnormalities including fibrosis, dilated cardiomyopathy and inflammation. The younger girl also had a cardiac arrest at the age of 15 and died suddenly after consuming 1-2 beers, 3 years after her sister´s first incident. Autopsy of the heart revealed acute myocarditis without structural alterations. Multigene panel analysis (not including PPA2) showed SCN5A and CACNA1D variants in both sisters and their healthy mother. Six years later duo exome allowed the diagnosis of an autosomal recessive PPA2-related mitochondriopathy. We discuss the molecular results and clinical picture of our patients compared to other PPA2-related cases. We highlight the diagnostic contribution of multigene panels and exome analysis. The genetic diagnosis is important for medical care and for everyday life, specifically because alcohol intake can result in cardiac arrest and should be strictly avoided. Conclusion: Duo exome sequencing clarified the diagnosis of PPA2-related mitochondriopathy in two sisters with isolated cardiac features and sudden cardiac arrest triggered by minimal amounts of alcohol. What is Known: • Multigene-Panel or exome analysis is a valuable tool to identify genetic causes of hereditary cardiac arrhythmias. • Variants of unknown significance can lead to misinterpretation. PPA2-related mitochondriopathy is a very rare autosomal recessive condition that is normally fatal in infancy. What is New: • Duo exome analysis in two teeenage sisters with cardiac arrest revealed a homozygous mild PPA2 mutation as the underlying pathology restricted to the heart muscle.
Topics: Female; Adolescent; Humans; Beer; Heart Arrest; Mutation; Death, Sudden, Cardiac; Arrhythmias, Cardiac; Mitochondrial Proteins; Inorganic Pyrophosphatase
PubMed: 37269378
DOI: 10.1007/s00431-023-05034-9 -
Pharmacogenomics Jun 20236-mercaptopurine usage is associated with myelotoxicity and increased risk in patients carrying metabolism-related genetic variations. This study aimed to determine the...
6-mercaptopurine usage is associated with myelotoxicity and increased risk in patients carrying metabolism-related genetic variations. This study aimed to determine the frequency of candidate gene polymorphisms and their association with 6-mercaptopurine intolerance. A total of 41 patients on acute lymphoblastic leukaemia treatment were genotyped for and (rs116855232) alleles, and their association with dose intensity was analyzed. The defective allele frequency was 9.8%. The median maintenance dose intensity for participants was considerably lower (47%) when compared with the wild-type (77%), although not statistically significant. This is the first pharmacogenetics study carried out in a black Zimbabwean leukemia patient cohort. The high defective (9.8%) allele frequency points to the potential utility of pharmacogenetics testing for safe usage of 6-mercaptopurine in this population.
Topics: Humans; Mercaptopurine; Pharmacogenetics; Zimbabwe; Antimetabolites, Antineoplastic; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Methyltransferases; Pyrophosphatases
PubMed: 37248698
DOI: 10.2217/pgs-2023-0026 -
Seminars in Cancer Biology Sep 2023Reactive oxygen species (ROS) are common products of normal cellular metabolism, but their elevated levels can result in nucleotide modifications. These modified or... (Review)
Review
Reactive oxygen species (ROS) are common products of normal cellular metabolism, but their elevated levels can result in nucleotide modifications. These modified or noncanonical nucleotides often integrate into nascent DNA during replication, causing lesions that trigger DNA repair mechanisms such as the mismatch repair machinery and base excision repair. Four superfamilies of sanitization enzymes can effectively hydrolyze noncanonical nucleotides from the precursor pool and eliminate their unintended incorporation into DNA. Notably, we focus on the representative MTH1 NUDIX hydrolase, whose enzymatic activity is ostensibly nonessential under normal physiological conditions. Yet, the sanitization attributes of MTH1 are more prevalent when ROS levels are abnormally high in cancer cells, rendering MTH1 an interesting target for developing anticancer treatments. We discuss multiple MTH1 inhibitory strategies that have emerged in recent years, and the potential of NUDIX hydrolases as plausible targets for the development of anticancer therapeutics.
Topics: Antineoplastic Agents; Humans; Reactive Oxygen Species; Nudix Hydrolases; DNA Repair Enzymes; Phosphoric Monoester Hydrolases; Nucleotides
PubMed: 37211293
DOI: 10.1016/j.semcancer.2023.05.005