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Journal of Molecular Medicine (Berlin,... Jun 2024Multiple theories have been proposed to explain the pathogenesis of early-onset preeclampsia (EOPE), and angiogenic dysfunction is an important part of this...
Multiple theories have been proposed to explain the pathogenesis of early-onset preeclampsia (EOPE), and angiogenic dysfunction is an important part of this pathogenesis. Carnitine palmitoyltransferase (CPT1A) is a key rate-limiting enzyme in the metabolic process of fatty acid oxidation (FAO). FAO regulates endothelial cell (EC) proliferation during vascular germination and is also essential for ab initio deoxyribonucleotide synthesis, but its role in EOPE needs to be further elucidated. In the present study, we investigated its functional role in EOPE by targeting the circHIPK3/miR-124-3p/CPT1A axis. In our study, reduced expression of circHIPK3 and CPT1A and increased expression of miR-124-3p in placental tissues from patients with EOPE were associated with EC dysfunction. Here, we confirmed that CPT1A regulates fatty acid oxidative activity, cell proliferation, and tube formation in ECs by regulating FAO. Functionally, knockdown of circHIPK3 suppressed EC angiogenesis by inhibiting CPT1A-mediated fatty acid oxidative activity, which was ameliorated by CPT1A overexpression. In addition, circHIPK3 regulates CPT1A expression by sponging miR-124-3p. Hence, circHIPK3 knockdown reduced fatty acid oxidation in ECs by sponging miR-124-3p in a CPT1A-dependent manner and inhibited EC proliferation and tube formation, which may have led to aberrant angiogenesis in EOPE. Thus, strategies targeting CPT1A-driven FAO may be promising approaches for the treatment of EOPE. KEY MESSAGES: Decreased Carnitine palmitoyltransferase (CPT1A) expression in preeclampsia(PE). CPT1A overexpression promotes FAO activity and tube formation in ECs. CircHIPK3 can affect CPT1A expression and impaire angiogenesis of EOPE. CircHIPK3 regulates CPT1A expression by acting as a ceRNA of miR-124-3p in HUVECs. Confirming the effect of circHIPK3/miR-124-3p/CPT1A axis on EOPE.
PubMed: 38904677
DOI: 10.1007/s00109-024-02461-5 -
Nature Communications Jun 2024C2'-halogenation has been recognized as an essential modification to enhance the drug-like properties of nucleotide analogs. The direct C2'-halogenation of the...
C2'-halogenation has been recognized as an essential modification to enhance the drug-like properties of nucleotide analogs. The direct C2'-halogenation of the nucleotide 2'-deoxyadenosine-5'-monophosphate (dAMP) has recently been achieved using the Fe(II)/α-ketoglutarate-dependent nucleotide halogenase AdaV. However, the limited substrate scope of this enzyme hampers its broader applications. In this study, we report two halogenases capable of halogenating 2'-deoxyguanosine monophosphate (dGMP), thereby expanding the family of nucleotide halogenases. Computational studies reveal that nucleotide specificity is regulated by the binding pose of the phosphate group. Based on these findings, we successfully engineered the substrate specificity of these halogenases by mutating second-sphere residues. This work expands the toolbox of nucleotide halogenases and provides insights into the regulation mechanism of nucleotide specificity.
Topics: Substrate Specificity; Protein Engineering; Halogenation; Nucleotides; Deoxyguanine Nucleotides; Escherichia coli
PubMed: 38898020
DOI: 10.1038/s41467-024-49147-7 -
World Journal of Hepatology May 2024Metabolic-dysfunction associated steatotic liver disease (MASLD) is a hepatic manifestation of metabolic syndrome. Studies suggest ornithine aspartate (LOLA) as drug...
BACKGROUND
Metabolic-dysfunction associated steatotic liver disease (MASLD) is a hepatic manifestation of metabolic syndrome. Studies suggest ornithine aspartate (LOLA) as drug therapy.
AIM
To analyze the influence of LOLA intake on gut microbiota using a nutritional model of MASLD.
METHODS
Adult male Sprague Dawley rats were randomized into three groups: Control (10 rats fed with a standard diet), MASLD (10 rats fed with a high-fat and choline-deficient diet), and LOLA (10 rats receiving 200 mg/kg/d LOLA, after the 16 week receiving high-fat and choline-deficient diet). After 28 wk of the experiment, animals were euthanized, and feces present in the intestine were collected. Following fecal DNA extraction, the V4 region of the 16S rRNA gene was amplified followed by sequencing in an Ion S5™ system.
RESULTS
Alpha and beta diversity metrics were comparable between MASLD and LOLA. 3 OTUs were differentially abundant between MASLD and LOLA, which belong to the species , , and . The functional prediction provided two different metabolic profiles between MASLD and LOLA. The 9 pathways differentially abundant in MASLD are related to a change in energy source, adenosine/purine nucleotides degradation as well as guanosine and adenosine deoxyribonucleotides biosynthesis. The 14 pathways differentially abundant in LOLA are associated with four major metabolic functions primarily influenced by L-aspartate, including tricarboxylic acid cycle pathways, purine/guanosine nucleotides biosynthesis, pyrimidine ribonucleotides biosynthesis and salvage as well as lipid IVA biosynthesis.
CONCLUSION
Although LOLA had no influence on alpha and beta diversity in this nutritional model of MASLD, it was associated with changes in specific gut microbes and their related metabolic pathways.
PubMed: 38818297
DOI: 10.4254/wjh.v16.i5.832 -
Science Advances May 2024The replication accuracy of DNA polymerase gamma (Pol γ) is essential for mitochondrial genome integrity. Mutation of human Pol γ arginine-853 has been linked to...
The replication accuracy of DNA polymerase gamma (Pol γ) is essential for mitochondrial genome integrity. Mutation of human Pol γ arginine-853 has been linked to neurological diseases. Although not a catalytic residue, Pol γ arginine-853 mutants are void of polymerase activity. To identify the structural basis for the disease, we determined a crystal structure of the Pol γ mutant ternary complex with correct incoming nucleotide 2'-deoxycytidine 5'-triphosphate (dCTP). Opposite to the wild type that undergoes open-to-closed conformational changes when bound to a correct nucleotide that is essential for forming a catalytically competent active site, the mutant complex failed to undergo the conformational change, and the dCTP did not base pair with its Watson-Crick complementary templating residue. Our studies revealed that arginine-853 coordinates an interaction network that aligns the 3'-end of primer and dCTP with the catalytic residues. Disruption of the network precludes the formation of Watson-Crick base pairing and closing of the active site, resulting in an inactive polymerase.
Topics: Base Pairing; Catalytic Domain; Humans; DNA Polymerase gamma; Models, Molecular; Mutation; Deoxycytosine Nucleotides; Crystallography, X-Ray; Protein Binding
PubMed: 38787958
DOI: 10.1126/sciadv.adl3214 -
Biochemistry Jun 2024The catalytic function of DNA polymerase β (pol β) fulfills the gap-filling requirement of the base excision DNA repair pathway by incorporating a single nucleotide...
The catalytic function of DNA polymerase β (pol β) fulfills the gap-filling requirement of the base excision DNA repair pathway by incorporating a single nucleotide into a gapped DNA substrate resulting from the removal of damaged DNA bases. Most importantly, pol β can select the correct nucleotide from a pool of similarly structured nucleotides to incorporate into DNA in order to prevent the accumulation of mutations in the genome. Pol β is likely to employ various mechanisms for substrate selection. Here, we use dCTP analogues that have been modified at the β,γ-bridging group of the triphosphate moiety to monitor the effect of leaving group basicity of the incoming nucleotide on precatalytic conformational changes, which are important for catalysis and selectivity. It has been previously shown that there is a linear free energy relationship between leaving group p and the chemical transition state. Our results indicate that there is a similar relationship with the rate of a precatalytic conformational change, specifically, the closing of the fingers subdomain of pol β. In addition, by utilizing analogue β,γ-CHX stereoisomers, we identified that the orientation of the β,γ-bridging group relative to R183 is important for the rate of fingers closing, which directly influences chemistry.
Topics: DNA Polymerase beta; Protein Conformation; Humans; Deoxycytosine Nucleotides; Substrate Specificity; Models, Molecular; Kinetics; DNA; DNA Repair
PubMed: 38780930
DOI: 10.1021/acs.biochem.4c00065 -
DNA Repair Jul 2024MutT proteins belong to the Nudix hydrolase superfamily that includes a diverse group of Mg requiring enzymes. These proteins use a generalized substrate, nucleoside...
MutT proteins belong to the Nudix hydrolase superfamily that includes a diverse group of Mg requiring enzymes. These proteins use a generalized substrate, nucleoside diphosphate linked to a chemical group X (NDP-X), to produce nucleoside monophosphate (NMP) and the moiety X linked with phosphate (XP). E. coli MutT (EcoMutT) and mycobacterial MutT1 (MsmMutT1) belong to the Nudix hydrolase superfamily that utilize 8-oxo-(d)GTP (referring to both 8-oxo-GTP or 8-oxo-dGTP). However, predominant products of their activities are different. While EcoMutT produces 8-oxo-(d)GMP, MsmMutT1 gives rise to 8-oxo-(d)GDP. Here, we show that the altered cleavage specificities of the two proteins are largely a consequence of the variation at the equivalent of Gly37 (G37) in EcoMutT to Lys (K65) in the MsmMutT1. Remarkably, mutations of G37K (EcoMutT) and K65G (MsmMutT1) switch their cleavage specificities to produce 8-oxo-(d)GDP, and 8-oxo-(d)GMP, respectively. Further, a time course analysis using 8-oxo-GTP suggests that MsmMutT1(K65G) hydrolyses 8-oxo-(d)GTP to 8-oxo-(d)GMP in a two-step reaction via 8-oxo-(d)GDP intermediate. Expectedly, unlike EcoMutT (G37K) and MsmMutT1, EcoMutT and MsmMutT1 (K65G) rescue an E. coli ΔmutT strain, better by decreasing A to C mutations.
Topics: Escherichia coli Proteins; Mycobacterium smegmatis; Substrate Specificity; Deoxyguanine Nucleotides; Escherichia coli; Bacterial Proteins; Amino Acid Substitution; Pyrophosphatases; Phosphoric Monoester Hydrolases; Guanosine Triphosphate
PubMed: 38776712
DOI: 10.1016/j.dnarep.2024.103693 -
Nucleic Acids Research Jun 2024Cancer cells produce vast quantities of reactive oxygen species, leading to the accumulation of toxic nucleotides as 8-oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate...
Cancer cells produce vast quantities of reactive oxygen species, leading to the accumulation of toxic nucleotides as 8-oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate (8-oxo-dGTP). The human MTH1 protein catalyzes the hydrolysis of 8-oxo-dGTP, and cancer cells are dependent on MTH1 for their survival. MTH1 inhibitors are possible candidates for a class of anticancer drugs; however, a reliable screening system using live cells has not been developed. Here we report a visualization method for 8-oxo-dGTP and its related nucleotides in living cells. Escherichia coli MutT, a functional homologue of MTH1, is divided into the N-terminal (1-95) and C-terminal (96-129) parts (Mu95 and 96tT, respectively). Mu95 and 96tT were fused to Ash (assembly helper tag) and hAG (Azami Green), respectively, to visualize the nucleotides as fluorescent foci formed upon the Ash-hAG association. The foci were highly increased when human cells expressing Ash-Mu95 and hAG-96tT were treated with 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) and 8-oxo-dGTP. The foci formation by 8-oxo-dG(TP) was strikingly enhanced by the MTH1 knockdown. Moreover, known MTH1 inhibitors and oxidizing reagents also increased foci. This is the first system that visualizes damaged nucleotides in living cells, provides an excellent detection method for the oxidized nucleotides and oxidative stress, and enables high throughput screening for MTH1 inhibitors.
Topics: Humans; Deoxyguanine Nucleotides; DNA Repair Enzymes; Escherichia coli; Escherichia coli Proteins; Guanine Nucleotides; Oxidation-Reduction; Phosphoric Monoester Hydrolases; Pyrophosphatases
PubMed: 38738661
DOI: 10.1093/nar/gkae371 -
Insect Science Apr 2024Spermatogenesis is critical for insect reproduction and the process is regulated by multiple genes. Glycosyltransferases have been shown to participate in the...
Spermatogenesis is critical for insect reproduction and the process is regulated by multiple genes. Glycosyltransferases have been shown to participate in the development of Drosophila melanogaster; however, their role in spermatogenesis is still unclear. In this study, we found that α1,4-galactosyltransferase 1 (α4GT1) was expressed at a significantly higher level in the testis than in the ovary of Drosophila. Importantly, the hatching rate was significantly decreased when α4GT1 RNA interference (RNAi) males were crossed with w females, with only a few mature sperm being present in the seminal vesicle of α4GT1 RNAi flies. Immunofluorescence staining further revealed that the individualization complex (IC) in the testes from α4GT1 RNAi flies was scattered and did not move synchronically, compared with the clustered IC observed in the control flies. Terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay showed that apoptosis signals in the sperm bundles of α4GT1 RNAi flies were significantly increased. Moreover, the expression of several individualization-related genes, such as Shrub, Obp44a and Hanabi, was significantly decreased, whereas the expression of several apoptosis-related genes, including Dronc and Drice, was significantly increased in the testes of α4GT1 RNAi flies. Together, these results suggest that α4GT1 may play dual roles in Drosophila spermatogenesis by regulating the sperm individualization process and maintaining the survival of sperm bundles.
PubMed: 38643371
DOI: 10.1111/1744-7917.13369 -
BMC Pediatrics Apr 2024Dilated cardiomyopathy (DCMP) is characterized by the enlargement and weakening of the heart and is a major cause of heart failure in children. Infection and nutritional...
BACKGROUND
Dilated cardiomyopathy (DCMP) is characterized by the enlargement and weakening of the heart and is a major cause of heart failure in children. Infection and nutritional deficiencies are culprits for DCMP. Zinc is an important nutrient for human health due to its anti-oxidant effect that protects cell against oxidative damage. This case-control study aimed to investigate the relationship between dietary intake of zinc and selenium and the risk of DCMP in pediatric patients.
METHODS
A total of 36 DCMP patients and 72 matched controls were recruited, and their dietary intakes were assessed via a validated food frequency questionnaire. We used chi-square and sample T-test for qualitative and quantitative variables, respectively. Logistic regression analysis was applied to assess the relationship between selenium and zinc intake with the risk of DCMP.
RESULTS
After fully adjusting for confounding factors, analyses showed that selenium (OR = 0.19, CI = 0.057-0.069, P trend < 0.011) and zinc (OR = 0.12, CI = 0.035-0.046, P trend < 0.002) intake were strongly associated with 81% and 88% lower risk of pediatric DCMP, respectively.
CONCLUSIONS
This study highlights the protective role of adequate dietary intake of selenium and zinc in decreasing the risk of DCMP in children. Malnutrition may exacerbate the condition and addressing these micronutrient deficiencies may improve the cardiac function. Further studies are recommended to detect the underlying mechanisms and dietary recommendations for DCMP prevention.
Topics: Humans; Child; Selenium; Case-Control Studies; Cardiomyopathy, Dilated; Deoxycytidine Monophosphate; Zinc; Malnutrition
PubMed: 38605385
DOI: 10.1186/s12887-024-04706-1 -
Journal of Functional Biomaterials Mar 2024Utilizing the immune system as a strategy for disease prevention and treatment is promising, especially with dendritic cells (DCs) playing a central role in adaptive...
Utilizing the immune system as a strategy for disease prevention and treatment is promising, especially with dendritic cells (DCs) playing a central role in adaptive immune responses. The unique properties of DCs drive interest in developing materials for cell-based therapy and immune modulation. Injectable systems require syringe-compatible scaffolds, while hydrogels, like alginate, known for their programmability and biocompatibility, offer a versatile platform for immune medicine enhancement through easy preparation and room-temperature cross-linking. In this study, we synthesized alginate balls loaded with DCs or cytosine-phosphorothioate-guanine deoxyribonucleotide (CpG DNA) microparticles, aiming for long-term immune cell culture with potential immune stimulation effects. Encapsulated DCs exhibited proliferation within the alginate balls for up to 7 days, and CpG MPs were uniformly dispersed, which can facilitate uptake by DCs. This was supported by the result that DCs effectively phagocytosed CpG microparticles in a 2D environment. After the uptake of CpG MPs, the alginate balls with CpG-MP-uptaken DCs were synthesized successfully. The injectable properties of the alginate balls were easily modulated by adjusting the syringe needle gauges. This innovative strategy holds substantial promise for advancing medical treatments, offering effective and comfortable solutions for controlled immune modulation.
PubMed: 38535252
DOI: 10.3390/jfb15030059