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Research (Washington, D.C.) 2024Poly (adenosine 5'-diphosphate-ribose) polymerase inhibitors (PARPi) are increasingly important in the treatment of ovarian cancer. However, more than 40% of deficient...
Poly (adenosine 5'-diphosphate-ribose) polymerase inhibitors (PARPi) are increasingly important in the treatment of ovarian cancer. However, more than 40% of deficient patients do not respond to PARPi, and wild-type cases do not show obvious benefit. In this study, we demonstrated that progesterone acted synergistically with niraparib in ovarian cancer cells by enhancing niraparib-mediated DNA damage and death regardless of status. This synergy was validated in an ovarian cancer organoid model and in vivo experiments. Furthermore, we found that progesterone enhances the activity of niraparib in ovarian cancer through inducing ferroptosis by up-regulating palmitoleic acid and causing mitochondrial damage. In clinical cohort, it was observed that progesterone prolonged the survival of patients with ovarian cancer receiving PARPi as second-line maintenance therapy, and high progesterone receptor expression combined with low glutathione peroxidase 4 (GPX4) expression predicted better efficacy of PARPi in patients with ovarian cancer. These findings not only offer new therapeutic strategies for PARPi poor response ovarian cancer but also provide potential molecular markers for predicting the PARPi efficacy.
PubMed: 38798714
DOI: 10.34133/research.0371 -
European Journal of Cell Biology Jun 2024Intracellular actin networks assemble through the addition of ATP-actin subunits at the growing barbed ends of actin filaments. This is followed by "aging" of the...
Intracellular actin networks assemble through the addition of ATP-actin subunits at the growing barbed ends of actin filaments. This is followed by "aging" of the filament via ATP hydrolysis and subsequent phosphate release. Aged ADP-actin subunits thus "treadmill" through the filament before being released back into the cytoplasmic monomer pool as a result of depolymerization at filament pointed ends. The necessity for aging before filament disassembly is reinforced by preferential binding of cofilin to aged ADP-actin subunits over newly-assembled ADP-P actin subunits in the filament. Consequently, investigations into how cofilin influences pointed-end depolymerization have, thus far, focused exclusively on aged ADP-actin filaments. Using microfluidics-assisted Total Internal Reflection Fluorescence (mf-TIRF) microscopy, we reveal that, similar to their effects on ADP filaments, cofilin and cyclase-associated protein (CAP) also promote pointed-end depolymerization of ADP-P filaments. Interestingly, the maximal rates of ADP-P filament depolymerization by CAP and cofilin together remain approximately 20-40 times lower than for ADP filaments. Further, we find that the promotion of ADP-P pointed-end depolymerization is conserved for all three mammalian cofilin isoforms. Taken together, the mechanisms presented here open the possibility of newly-assembled actin filaments being directly disassembled from their pointed-ends, thus bypassing the slow step of P release in the aging process.
Topics: Actin Cytoskeleton; Animals; Actins; Actin Depolymerizing Factors; Adenosine Diphosphate; Rabbits; Mice; Polymerization; Cofilin 1
PubMed: 38796920
DOI: 10.1016/j.ejcb.2024.151423 -
Microorganisms May 2024In cyanobacteria and chloroplasts (in algae and plants), ATP synthase plays a pivotal role as a photosynthetic membrane complex responsible for producing ATP from... (Review)
Review
In cyanobacteria and chloroplasts (in algae and plants), ATP synthase plays a pivotal role as a photosynthetic membrane complex responsible for producing ATP from adenosine diphosphate and inorganic phosphate, utilizing a proton motive force gradient induced by photosynthesis. These two ATP synthases exhibit similarities in gene organization, amino acid sequences of subunits, structure, and functional mechanisms, suggesting that cyanobacterial ATP synthase is probably the evolutionary precursor to chloroplast ATP synthase. In this review, we explore the precise synthesis and assembly of ATP synthase subunits to address the uneven stoichiometry within the complex during transcription, translation, and assembly processes. We also compare the regulatory strategies governing ATP synthase activity to meet varying energy demands in cyanobacteria and chloroplasts amid fluctuating natural environments. Furthermore, we delve into the role of ATP synthase in stress tolerance and photosynthetic carbon fixation efficiency in oxygenic photosynthetic organisms (OPsOs), along with the current researches on modifying ATP synthase to enhance carbon fixation efficiency under stress conditions. This review aims to offer theoretical insights and serve as a reference for understanding the functional mechanisms of ATP synthase, sparking innovative ideas for enhancing photosynthetic carbon fixation efficiency by utilizing ATP synthase as an effective module in OPsOs.
PubMed: 38792770
DOI: 10.3390/microorganisms12050940 -
International Journal of Molecular... May 2024The excessive activation of frog eggs, referred to as overactivation, can be initiated by strong oxidative stress, leading to expedited calcium-dependent non-apoptotic...
The excessive activation of frog eggs, referred to as overactivation, can be initiated by strong oxidative stress, leading to expedited calcium-dependent non-apoptotic cell death. Overactivation also occurs spontaneously, albeit at a low frequency, in natural populations of spawned frog eggs. Currently, the cytological and biochemical events of the spontaneous process have not been characterized. In the present study, we demonstrate that the spontaneous overactivation of frog eggs, similarly to oxidative stress- and mechanical stress-induced overactivation, is characterized by the fast and irreversible contraction of the egg's cortical layer, an increase in egg size, the depletion of intracellular ATP, a drastic increase in the intracellular ADP/ATP ratio, and the degradation of M phase-specific cyclin B2. These events manifest in eggs in the absence of caspase activation within one hour of triggering overactivation. Importantly, substantial amounts of ATP and ADP leak from the overactivated eggs, indicating that plasma membrane integrity is compromised in these cells. The rupture of the plasma membrane and acute depletion of intracellular ATP explicitly define necrotic cell death. Finally, we report that egg overactivation can occur in the frog's genital tract. Our data suggest that mechanical stress may be a key factor promoting egg overactivation during oviposition in frogs.
Topics: Animals; Adenosine Triphosphate; Ovum; Necrosis; Xenopus laevis; Female; Oxidative Stress; Adenosine Diphosphate; Cell Death; Cell Membrane; Stress, Mechanical
PubMed: 38791359
DOI: 10.3390/ijms25105321 -
International Journal of Molecular... May 2024The genome sequencing of supplies a general overview of the map of genes involved in secondary metabolite synthesis. genomic data reveals that this phytopathogenic...
The genome sequencing of supplies a general overview of the map of genes involved in secondary metabolite synthesis. genomic data reveals that this phytopathogenic fungus has seven sesquiterpene cyclase () genes that encode proteins involved in the farnesyl diphosphate cyclization. Three sesquiterpene cyclases (BcStc1, BcStc5 and BcStc7) are characterized, related to the biosynthesis of botrydial, abscisic acid and (+)-4-epi-eremophilenol, respectively. However, the role of the other four sesquiterpene cyclases (BcStc2, BcStc3, BcStc4 and BcStc6) remains unknown. BcStc3 is a well-conserved protein with homologues in many fungal species, and here, we undertake its functional characterization in the lifecycle of the fungus. A null mutant Δ and an overexpressed- transformant (Ov) are generated, and both strains show the deregulation of those other sesquiterpene cyclase-encoding genes (, and ). These results suggest a co-regulation of the expression of the sesquiterpene cyclase gene family in . The phenotypic characterization of both transformants reveals that BcStc3 is involved in oxidative stress tolerance, the production of reactive oxygen species and virulence. The metabolomic analysis allows the isolation of characteristic polyketides and eremophilenols from the secondary metabolism of , although no sesquiterpenes different from those already described are identified.
Topics: Botrytis; Sesquiterpenes; Fungal Proteins; Gene Expression Regulation, Fungal; Oxidative Stress; Carbon-Carbon Lyases
PubMed: 38791163
DOI: 10.3390/ijms25105125 -
Toxins Apr 2024Recent discoveries establish DNA and RNA as bona fide substrates for ADP-ribosylation. NADAR ("NAD- and ADP-ribose"-associated) enzymes reverse guanine ADP-ribosylation...
Recent discoveries establish DNA and RNA as bona fide substrates for ADP-ribosylation. NADAR ("NAD- and ADP-ribose"-associated) enzymes reverse guanine ADP-ribosylation and serve as antitoxins in the DarT-NADAR operon. Although NADARs are widespread across prokaryotes, eukaryotes, and viruses, their specificity and broader physiological roles remain poorly understood. Using phylogenetic and biochemical analyses, we further explore de-ADP-ribosylation activity and antitoxin functions of NADAR domains. We demonstrate that different subfamilies of NADAR proteins from representative strains and an -infecting phage retain biochemical activity while displaying specificity in providing protection from toxic guanine ADP-ribosylation in cells. Furthermore, we identify a myxobacterial enzyme within the YbiA subfamily that functions as an antitoxin for its associated DarT-unrelated ART toxin, which we termed YarT, thus presenting a hitherto uncharacterised ART-YbiA toxin-antitoxin pair. Our studies contribute to the burgeoning field of DNA ADP-ribosylation, supporting its physiological relevance within and beyond bacterial toxin-antitoxin systems. Notably, the specificity and confinement of NADARs to non-mammals infer their potential as highly specific targets for antimicrobial drugs with minimal off-target effects.
Topics: ADP-Ribosylation; Escherichia coli; Escherichia coli Proteins; Bacterial Toxins; Adenosine Diphosphate Ribose; Phylogeny; Toxin-Antitoxin Systems; DNA, Bacterial; DNA
PubMed: 38787060
DOI: 10.3390/toxins16050208 -
Insects Apr 2024UDP-glycosyltransferases (UGTs) are a diverse superfamily of enzymes. Insects utilize uridine diphosphate-glucose (UDP-glucose) as a glycosyl donor for glycosylation in...
UDP-glycosyltransferases (UGTs) are a diverse superfamily of enzymes. Insects utilize uridine diphosphate-glucose (UDP-glucose) as a glycosyl donor for glycosylation in vivo, involved in the glycosylation of lipophilic endosymbionts and xenobiotics, including phytotoxins. UGTs act as second-stage detoxification metabolizing enzymes, which are essential for the detoxification metabolism of insecticides and benzoxazine compounds. However, the UGT genes responsible for specific glycosylation functions in are unclear at present. In this study, we utilized CRISPR/Cas9 to produce a strain to explore its possible function in governing sensitivity to chemical insecticides or benzoxazinoids. The bioassay results suggested that the strain was significantly more sensitive to chlorantraniliprole, emamectin benzoate, and benzoxazinoids than the wild-type strains. This finding suggests that the overexpression of the gene may be linked to resistance to pesticides (chlorantraniliprole and emamectin benzoate) as well as benzoxazinoids (BXDs).
PubMed: 38786870
DOI: 10.3390/insects15050314 -
Microbiology Spectrum May 2024Isoprenoids are a diverse family of compounds that are synthesized from two isomeric compounds, isopentenyl diphosphate and dimethylallyl diphosphate. In most bacteria,...
UNLABELLED
Isoprenoids are a diverse family of compounds that are synthesized from two isomeric compounds, isopentenyl diphosphate and dimethylallyl diphosphate. In most bacteria, isoprenoids are produced from the essential methylerythritol phosphate (MEP) pathway. The terminal enzymes of the MEP pathway IspG and IspH are [4Fe-4S] cluster proteins, and in the substrates of IspG and IspH accumulate in cells in response to O, suggesting possible lability of their [4Fe-4S] clusters. Here, we show using complementation assays in that even under anaerobic conditions, IspG and IspH are not as functional as their counterparts, requiring higher levels of expression to rescue viability. A deficit of the sulfur utilization factor (SUF) Fe-S cluster biogenesis pathway did not explain the reduced function of IspG and IspH since no improvement in viability was observed in expressing the SUF pathway or having increased expression of the SUF pathway. Complementation of single and double mutants with various combinations of and IspG and IspH indicated that optimal growth required the pairing of IspG and IspH from the same species. Furthermore, IspH conferred an O-sensitive growth defect to that could be partially rescued by co-expression of IspG. analysis showed O sensitivity of the [4Fe-4S] cluster of both IspG and IspH. Altogether, our data indicate an important role of the cognate protein IspG in IspH function under both aerobic and anaerobic conditions.
IMPORTANCE
Isoprenoids are one of the largest classes of natural products, exhibiting diversity in structure and function. They also include compounds that are essential for cellular life across the biological world. In bacteria, isoprenoids are derived from two precursors, isopentenyl diphosphate and dimethylallyl diphosphate, synthesized primarily by the methylerythritol phosphate pathway. The aerotolerant has the potential for methylerythritol phosphate pathway engineering by diverting some of the glucose that is typically efficiently converted into ethanol to produce isoprenoid precursors to make bioproducts and biofuels. Our data revealed the surprising finding that IspG and IspH need to be co-optimized to improve flux via the methyl erythritol phosphate pathway in part to evade the oxygen sensitivity of IspH.
PubMed: 38785428
DOI: 10.1128/spectrum.04256-23 -
RSC Medicinal Chemistry May 2024Most pathogenic bacteria, apicomplexan parasites and plants rely on the methylerythritol phosphate (MEP) pathway to obtain precursors of isoprenoids. 1-Deoxy-d-xylulose...
Most pathogenic bacteria, apicomplexan parasites and plants rely on the methylerythritol phosphate (MEP) pathway to obtain precursors of isoprenoids. 1-Deoxy-d-xylulose 5-phosphate synthase (DXPS), a thiamine diphosphate (ThDP)-dependent enzyme, catalyses the first and rate-limiting step of the MEP pathway. Due to its absence in humans, DXPS is considered as an attractive target for the development of anti-infectious agents and herbicides. Ketoclomazone is one of the earliest reported inhibitors of DXPS and antibacterial and herbicidal activities have been documented. This study investigated the activity of ketoclomazone on DXPS from various species, as well as the broader ThDP-dependent enzyme family. To gain further insights into the inhibition, we have prepared analogues of ketoclomazone and evaluated their activity in biochemical and computational studies. Our findings support the potential of ketoclomazone as a selective antibacterial agent.
PubMed: 38784473
DOI: 10.1039/d4md00083h -
Frontiers in Medicine 2024Crigler-Najjar syndrome (CNS) is caused by mutations in uridine 5'-diphosphate glucuronyltransferase (UGT1A1) resulting in enzyme deficiency and hyperbilirubinemia. Type...
BACKGROUND
Crigler-Najjar syndrome (CNS) is caused by mutations in uridine 5'-diphosphate glucuronyltransferase (UGT1A1) resulting in enzyme deficiency and hyperbilirubinemia. Type II CNS patients could respond to phenobarbital treatment and survive. This study presents a rare case of type II CNS.
CASE SUMMARY
The proband was a 29-year-old male patient admitted with severe jaundice. A hepatic biopsy showed bullous steatosis of the peri-central veins of the hepatic lobule, sediment of bile pigment, and mild periportal inflammation with normal liver plate structure. The type II CNS was diagnosed by routine genomic sequencing which found that the proband with the Gry71Arg/Tyr486Asp compound heterozygous mutations in the UGT1A1 gene. After treatment with phenobarbital (180 mg/day), his bilirubin levels fluctuated between 100 and 200 μmol/L for 6 months and without severe icterus.
CONCLUSION
Type II CNS could be diagnosed by routine gene sequencing and treated by phenobarbital.
PubMed: 38784231
DOI: 10.3389/fmed.2024.1354514