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1.
Environ Sci Technol ; 58(28): 12320-12329, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-38973717

ABSTRACT

Reducing air pollutants and CO2 emissions from energy utilization is crucial for achieving the dual objectives of clean air and carbon neutrality in China. Thus, an optimized health-oriented strategy is urgently needed. Herein, by coupling a CO2 and air pollutants emission inventory with response surface models for PM2.5-associated mortality, we shed light on the effectiveness of protecting human health and co-CO2 benefit from reducing fuel-related emissions and generate a health-oriented strategy for the Yangtze River Delta (YRD). Results reveal that oil consumption is the primary contributor to fuel-related PM2.5 pollution and premature deaths in the YRD. Significantly, curtailing fuel consumption in transportation is the most effective measure to alleviate the fuel-related PM2.5 health impact, which also has the greatest cobenefits for CO2 emission reduction on a regional scale. Reducing fuel consumption will achieve substantial health improvements especially in eastern YRD, with nonroad vehicle emission reductions being particularly impactful for health protection, while on-road vehicles present the greatest potential for CO2 reductions. Scenario analysis confirms the importance of mitigating oil consumption in the transportation sector in addressing PM2.5 pollution and climate change.


Subject(s)
Air Pollutants , Carbon Dioxide , China , Air Pollution/prevention & control , Rivers/chemistry , Particulate Matter , Humans , Vehicle Emissions
2.
J Adv Res ; 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39084404

ABSTRACT

INTRODUCTION: Exaggerated neutrophil recruitment and activation are the major features of pathological alterations in periodontitis, in which neutrophil extracellular traps (NETs) are considered to be responsible for inflammatory periodontal lesions. Despite the critical role of NETs in the development and progression of periodontitis, their specific functions and mechanisms remain unclear. OBJECTIVES: To demonstrate the important functions and specific mechanisms of NETs involved in periodontal immunopathology. METHODS: We performed single-cell RNA sequencing on gingival tissues from both healthy individuals and patients diagnosed with periodontitis. High-dimensional weighted gene co-expression network analysis and pseudotime analysis were then applied to characterize the heterogeneity of neutrophils. Animal models of periodontitis were treated with NETs inhibitors to investigate the effects of NETs in severe periodontitis. Additionally, we established a periodontitis prediction model based on NETs-related genes using six types of machine learning methods. Cell-cell communication analysis was used to identify ligand-receptor pairs among the major cell groups within the immune microenvironment. RESULTS: We constructed a single-cell atlas of the periodontal microenvironment and obtained nine major cell populations. We further identified a NETs-related subgroup (NrNeu) in neutrophils. An in vivo inhibition experiment confirmed the involvement of NETs in gingival inflammatory infiltration and alveolar bone absorption in severe periodontitis. We further screened three key NETs-related genes (PTGS2, MME and SLC2A3) and verified that they have the potential to predict periodontitis. Moreover, our findings revealed that gingival fibroblasts had the most interactions with NrNeu and that they might facilitate the production of NETs through the MIF-CD74/CXCR4 axis in periodontitis. CONCLUSION: This study highlights the pathogenic role of NETs in periodontal immunity and elucidates the specific regulatory relationship by which gingival fibroblasts activate NETs, which provides new insights into the clinical diagnosis and treatment of periodontitis.

3.
J Am Chem Soc ; 146(23): 15897-15907, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38818863

ABSTRACT

In the RNA World before the emergence of an RNA polymerase, nonenzymatic template copying would have been essential for the transmission of genetic information. However, the products of chemical copying with the canonical nucleotides (A, U, C, and G) are heavily biased toward the incorporation of G and C, which form a more stable base pair than A and U. We therefore asked whether replacing adenine (A) with diaminopurine (D) might lead to more efficient and less biased nonenzymatic template copying by making a stronger version of the A:U pair. As expected, primer extension substrates containing D bound to U in the template more tightly than substrates containing A. However, primer extension with D exhibited elevated reaction rates on a C template, leading to concerns about fidelity. Our crystallographic studies revealed the nature of the D:C mismatch by showing that D can form a wobble-type base pair with C. We then asked whether competition with G would decrease the mismatched primer extension. We performed nonenzymatic primer extension with all four activated nucleotides on randomized RNA templates containing all four letters and used deep sequencing to analyze the products. We found that the DUCG genetic system exhibited a more even product distribution and a lower mismatch frequency than the canonical AUCG system. Furthermore, primer extension is greatly reduced following all mismatches, including the D:C mismatch. Our study suggests that D deserves further attention for its possible role in the RNA World and as a potentially useful component of artificial nonenzymatic RNA replication systems.


Subject(s)
2-Aminopurine , RNA , RNA/chemistry , 2-Aminopurine/chemistry , 2-Aminopurine/analogs & derivatives , Base Pairing , Templates, Genetic , Nucleic Acid Conformation , Models, Molecular
4.
Nat Commun ; 15(1): 3789, 2024 May 06.
Article in English | MEDLINE | ID: mdl-38710693

ABSTRACT

The CUL3-RING E3 ubiquitin ligases (CRL3s) play an essential role in response to extracellular nutrition and stress stimuli. The ubiquitin ligase function of CRL3s is activated through dimerization. However, how and why such a dimeric assembly is required for its ligase activity remains elusive. Here, we report the cryo-EM structure of the dimeric CRL3KLHL22 complex and reveal a conserved N-terminal motif in CUL3 that contributes to the dimerization assembly and the E3 ligase activity of CRL3KLHL22. We show that deletion of the CUL3 N-terminal motif impairs dimeric assembly and the E3 ligase activity of both CRL3KLHL22 and several other CRL3s. In addition, we found that the dynamics of dimeric assembly of CRL3KLHL22 generates a variable ubiquitination zone, potentially facilitating substrate recognition and ubiquitination. These findings demonstrate that a CUL3 N-terminal motif participates in the assembly process and provide insights into the assembly and activation of CRL3s.


Subject(s)
Amino Acid Motifs , Cryoelectron Microscopy , Cullin Proteins , Receptors, Interleukin-17 , Ubiquitin-Protein Ligases , Ubiquitination , Cullin Proteins/metabolism , Cullin Proteins/chemistry , Cullin Proteins/genetics , Humans , Ubiquitin-Protein Ligases/metabolism , Ubiquitin-Protein Ligases/chemistry , Ubiquitin-Protein Ligases/genetics , HEK293 Cells , Protein Multimerization , Conserved Sequence , Protein Binding , Models, Molecular
5.
Environ Sci Technol ; 58(22): 9570-9581, 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38781138

ABSTRACT

The increasing level of O3 pollution in China significantly exacerbates the long-term O3 health damage, and an optimized health-oriented strategy for NOx and VOCs emission abatement is needed. Here, we developed an integrated evaluation and optimization system for the O3 control strategy by merging a response surface model for the O3-related mortality and an optimization module. Applying this system to the Yangtze River Delta (YRD), we evaluated driving factors for mortality changes from 2013 to 2017, quantified spatial and temporal O3-related mortality responses to precursor emission abatement, and optimized a health-oriented control strategy. Results indicate that insufficient NOx emission abatement combined with deficient VOCs control from 2013 to 2017 aggravated O3-related mortality, particularly during spring and autumn. Northern YRD should promote VOCs control due to higher VOC-limited characteristics, whereas fastening NOx emission abatement is more favorable in southern YRD. Moreover, promotion of NOx mitigation in late spring and summer and facilitating VOCs control in spring and autumn could further reduce O3-related mortality by nearly 10% compared to the control strategy without seasonal differences. These findings highlight that a spatially and temporally differentiated NOx and VOCs emission control strategy could gain more O3-related health benefits, offering valuable insights to regions with severe ozone pollution all over the world.


Subject(s)
Ozone , Volatile Organic Compounds , China , Air Pollutants , Humans , Nitrogen Oxides
6.
Biomed Pharmacother ; 175: 116605, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38688168

ABSTRACT

The recent Global Burden of Disease results have demonstrated that oral diseases are some of the most significant public health challenges facing the world. Owing to its specific localization advantage, superoxide dismutase 2 (SOD2 or MnSOD) has the ability to process the reactive oxygen species (ROS) produced by mitochondrial respiration before anything else, thereby impacting the occurrence and development of diseases. In this review, we summarize the processes of common oral diseases in which SOD2 is involved. SOD2 is upregulated in periodontitis to protect the tissue from the distant damage caused by excessive ROS and further reduce inflammatory progression. SOD2 also participates in the specific pathogenesis of oral cancers and dental diseases. The clinical application prospects of SOD2 in oral diseases will be discussed further, referencing the differences and relationship between oral diseases and other clinical systemic diseases.


Subject(s)
Disease Progression , Reactive Oxygen Species , Superoxide Dismutase , Humans , Superoxide Dismutase/metabolism , Reactive Oxygen Species/metabolism , Animals , Mouth Diseases/pathology , Mouth Diseases/enzymology , Oxidative Stress , Mitochondria/metabolism
7.
Natl Sci Rev ; 11(4): nwae007, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38495813

ABSTRACT

China currently has the highest acid deposition globally, yet research on its status, impacts, causes and controls is lacking. Here, we compiled data and calculated critical loads regarding acid deposition. The results showed that the abatement measures in China have achieved a sharp decline in the emissions of acidifying pollutants and a continuous recovery of precipitation pH, despite the drastic growth in the economy and energy consumption. However, the risk of ecological acidification and eutrophication showed no significant decrease. With similar emission reductions, the decline in areas at risk of acidification in China (7.0%) lags behind those in Europe (20%) or the USA (15%). This was because, unlike Europe and the USA, China's abatement strategies primarily target air quality improvement rather than mitigating ecological impacts. Given that the area with the risk of eutrophication induced by nitrogen deposition remained at 13% of the country even under the scenario of achieving the dual targets of air quality and carbon dioxide mitigation in 2035, we explored an enhanced ammonia abatement pathway. With a further 27% reduction in ammonia by 2035, China could largely eliminate the impacts of acid deposition. This research serves as a valuable reference for China's future acid deposition control and for other nations facing similar challenges.

8.
PNAS Nexus ; 3(3): pgae084, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38505692

ABSTRACT

The origin of life likely occurred within environments that concentrated cellular precursors and enabled their co-assembly into cells. Soda lakes (those dominated by Na+ ions and carbonate species) can concentrate precursors of RNA and membranes, such as phosphate, cyanide, and fatty acids. Subsequent assembly of RNA and membranes into cells is a long-standing problem because RNA function requires divalent cations, e.g. Mg2+, but Mg2+ disrupts fatty acid membranes. The low solubility of Mg-containing carbonates limits soda lakes to moderate Mg2+ concentrations (∼1 mM), so we investigated whether both RNAs and membranes function within these lakes. We collected water from Last Chance Lake and Goodenough Lake in Canada. Because we sampled after seasonal evaporation, the lake water contained ∼1 M Na+ and ∼1 mM Mg2+ near pH 10. In the laboratory, nonenzymatic, RNA-templated polymerization of 2-aminoimidazole-activated ribonucleotides occurred at comparable rates in lake water and standard laboratory conditions (50 mM MgCl2, pH 8). Additionally, we found that a ligase ribozyme that uses oligonucleotide substrates activated with 2-aminoimidazole was active in lake water after adjusting pH from ∼10 to 9. We also observed that decanoic acid and decanol assembled into vesicles in a dilute solution that resembled lake water after seasonal rains, and that those vesicles retained encapsulated solutes despite salt-induced flocculation when the external solution was replaced with dry-season lake water. By identifying compatible conditions for nonenzymatic and ribozyme-catalyzed RNA assembly, and for encapsulation by membranes, our results suggest that soda lakes could have enabled cellular life to emerge on Earth, and perhaps elsewhere.

9.
Chem Sci ; 15(6): 2158-2166, 2024 Feb 07.
Article in English | MEDLINE | ID: mdl-38332835

ABSTRACT

Charge separation is one of the most common consequences of the absorption of UV light by DNA. Recently, it has been shown that this process can enable efficient self-repair of cyclobutane pyrimidine dimers (CPDs) in specific short DNA oligomers such as the GAT[double bond, length as m-dash]T sequence. The mechanism was characterized as sequential electron transfer through the nucleobase stack which is controlled by the redox potentials of nucleobases and their sequence. Here, we demonstrate that the inverse sequence T[double bond, length as m-dash]TAG promotes self-repair with higher quantum yields (0.58 ± 0.23%) than GAT[double bond, length as m-dash]T (0.44 ± 0.18%) in a comparative study involving UV-irradiation experiments. After extended exposure to UV irradiation, a photostationary equilibrium between self-repair and damage formation is reached at 33 ± 13% for GAT[double bond, length as m-dash]T and at 40 ± 16% for T[double bond, length as m-dash]TAG, which corresponds to the maximum total yield of self-repair. Molecular dynamics and quantum mechanics/molecular mechanics (QM/MM) simulations allowed us to assign this disparity to better stacking overlap between the G and A bases, which lowers the energies of the key A-˙G+˙ charge transfer state in the dominant conformers of the T[double bond, length as m-dash]TAG tetramer. These conformational differences also hinder alternative photorelaxation pathways of the T[double bond, length as m-dash]TAG tetranucleotide, which otherwise compete with the sequential electron transfer mechanism responsible for CPD self-repair. Overall, we demonstrate that photoinduced electron transfer is strongly dependent on conformation and the availability of alternative photodeactivation mechanisms. This knowledge can be used in the identification and prediction of canonical and modified DNA sequences exhibiting efficient electron transfer. It also further contributes to our understanding of DNA self-repair and its potential role in the photochemical selection of the most photostable sequences on the early Earth.

10.
EMBO J ; 43(6): 1089-1109, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38360992

ABSTRACT

Cullin-RING E3 ubiquitin ligase (CRL) family members play critical roles in numerous biological processes and diseases including cancer and Alzheimer's disease. Oligomerization of CRLs has been reported to be crucial for the regulation of their activities. However, the structural basis for its regulation and mechanism of its oligomerization are not fully known. Here, we present cryo-EM structures of oligomeric CRL2FEM1B in its unneddylated state, neddylated state in complex with BEX2 as well as neddylated state in complex with FNIP1/FLCN. These structures reveal that asymmetric dimerization of N8-CRL2FEM1B is critical for the ubiquitylation of BEX2 while FNIP1/FLCN is ubiquitylated by monomeric CRL2FEM1B. Our data present an example of the asymmetric homo-dimerization of CRL. Taken together, this study sheds light on the ubiquitylation strategy of oligomeric CRL2FEM1B according to substrates with different scales.


Subject(s)
Ubiquitin-Protein Ligases , Humans , Cullin Proteins/metabolism , Neoplasms/metabolism , Nerve Tissue Proteins , Ubiquitin/metabolism , Ubiquitin-Protein Ligases/metabolism , Ubiquitination
11.
Nucleic Acids Res ; 52(5): 2174-2187, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-38348869

ABSTRACT

Oligonucleotide hybridization is crucial in various biological, prebiotic and nanotechnological processes, including gene regulation, non-enzymatic primer extension and DNA nanodevice assembly. Although extensive research has focused on the thermodynamics and kinetics of nucleic acid hybridization, the behavior of complex mixtures and the outcome of competition for target binding remain less well understood. In this study, we investigate the impact of mismatches and bulges in a 12 bp DNA or RNA duplex on its association (kon) and dissociation (koff) kinetics. We find that such defects have relatively small effects on the association kinetics, while the dissociation kinetics vary in a position-dependent manner by up to 6 orders of magnitude. Building upon this observation, we explored a competition scenario involving multiple oligonucleotides, and observed a transient low specificity of probe hybridization to fully versus partially complementary targets in solution. We characterize these long-lived metastable states and their evolution toward equilibrium, and show that sufficiently long-lived mis-paired duplexes can serve as substrates for prebiotically relevant chemical copying reactions. Our results suggest that transient low accuracy states may spontaneously emerge within all complex nucleic acid systems comprising a large enough number of competing strands, with potential repercussions for gene regulation in the realm of modern biology and the prebiotic preservation of genetic information.


Subject(s)
Nucleic Acid Hybridization , Oligonucleotides , DNA/chemistry , Kinetics , Oligonucleotides/genetics , Oligonucleotides/chemistry , RNA/chemistry , Thermodynamics
12.
J Am Chem Soc ; 146(6): 3861-3871, 2024 02 14.
Article in English | MEDLINE | ID: mdl-38293747

ABSTRACT

2-Thiouridine (s2U) is a nucleobase modification that confers enhanced efficiency and fidelity both on modern tRNA codon translation and on nonenzymatic and ribozyme-catalyzed RNA copying. We have discovered an unusual base pair between two 2-thiouridines that stabilizes an RNA duplex to a degree that is comparable to that of a native A:U base pair. High-resolution crystal structures indicate similar base-pairing geometry and stacking interactions in duplexes containing s2U:s2U compared to those with U:U pairs. Notably, the C═O···H-N hydrogen bond in the U:U pair is replaced with a C═S···H-N hydrogen bond in the s2U:s2U base pair. The thermodynamic stability of the s2U:s2U base pair suggested that this self-pairing might lead to an increased error frequency during nonenzymatic RNA copying. However, competition experiments show that s2U:s2U base-pairing induces only a low level of misincorporation during nonenzymatic RNA template copying because the correct A:s2U base pair outcompetes the slightly weaker s2U:s2U base pair. In addition, even if an s2U is incorrectly incorporated, the addition of the next base is greatly hindered. This strong stalling effect would further increase the effective fidelity of nonenzymatic RNA copying with s2U. Our findings suggest that s2U may enhance the rate and extent of nonenzymatic copying with only a minimal cost in fidelity.


Subject(s)
RNA, Catalytic , RNA , Thiouridine/analogs & derivatives , RNA/chemistry , Base Pairing , Thiouridine/chemistry , RNA, Catalytic/chemistry , Nucleic Acid Conformation
13.
Nat Commun ; 15(1): 759, 2024 Jan 26.
Article in English | MEDLINE | ID: mdl-38272905

ABSTRACT

Anion exchanger 2 (AE2) is an electroneutral Na+-independent Cl-/HCO3- exchanger belongs to the SLC4 transporter family. The widely expressed AE2 participates in a variety of physiological processes, including transepithelial acid-base secretion and osteoclastogenesis. Both the transmembrane domains (TMDs) and the N-terminal cytoplasmic domain (NTD) are involved in regulation of AE2 activity. However, the regulatory mechanism remains unclear. Here, we report a 3.2 Å cryo-EM structure of the AE2 TMDs in complex with PIP2 and a 3.3 Å full-length mutant AE2 structure in the resting state without PIP2. We demonstrate that PIP2 at the TMD dimer interface is involved in the substrate exchange process. Mutation in the PIP2 binding site leads to the displacement of TM7 and further stabilizes the interaction between the TMD and the NTD. Reduced substrate transport activity and conformation similar to AE2 in acidic pH indicating the central contribution of PIP2 to the function of AE2.


Subject(s)
Antiporters , Lipids , Humans , Chloride-Bicarbonate Antiporters/genetics , Antiporters/genetics , SLC4A Proteins , Mutation , Anion Transport Proteins/metabolism , Hydrogen-Ion Concentration
14.
Chem Commun (Camb) ; 59(91): 13603-13606, 2023 Nov 14.
Article in English | MEDLINE | ID: mdl-37899697

ABSTRACT

Nucleic acids can be damaged by ultraviolet (UV) irradiation, forming structural photolesions such as cyclobutane-pyrimidine-dimers (CPD). In modern organisms, sophisticated enzymes repair CPD lesions in DNA, but to our knowledge, no RNA-specific enzymes exist for CPD repair. Here, we show for the first time that RNA can protect itself from photolesions by an intrinsic UV-induced self-repair mechanism. This mechanism, prior to this study, has exclusively been observed in DNA and is based on charge transfer from CPD-adjacent bases. In a comparative study, we determined the quantum yields of the self-repair of the CPD-containing RNA sequence, GAU = U to GAUU (0.23%), and DNA sequence, d(GAT = T) to d(GATT) (0.44%), upon 285 nm irradiation via UV/Vis spectroscopy and HPLC analysis. After several hours of irradiation, a maximum conversion yield of ∼16% for GAU = U and ∼33% for d(GAT = T) was reached. We examined the dynamics of the intermediate charge transfer (CT) state responsible for the self-repair with ultrafast UV pump - IR probe spectroscopy. In the dinucleotides GA and d(GA), we found comparable quantum yields of the CT state of ∼50% and lifetimes on the order of several hundred picoseconds. Charge transfer in RNA strands might lead to reactions currently not considered in RNA photochemistry and may help understanding RNA damage formation and repair in modern organisms and viruses. On the UV-rich surface of the early Earth, these self-stabilizing mechanisms likely affected the selection of the earliest nucleotide sequences from which the first organisms may have developed.


Subject(s)
DNA Repair , Pyrimidine Dimers , Pyrimidine Dimers/chemistry , Pyrimidine Dimers/genetics , Pyrimidine Dimers/radiation effects , RNA , DNA/chemistry , Ultraviolet Rays , DNA Damage
15.
Nat Commun ; 14(1): 6157, 2023 10 03.
Article in English | MEDLINE | ID: mdl-37788993

ABSTRACT

BTR1 (SLC4A11) is a NH3 stimulated H+ (OH-) transporter belonging to the SLC4 family. Dysfunction of BTR1 leads to diseases such as congenital hereditary endothelial dystrophy (CHED) and Fuchs endothelial corneal dystrophy (FECD). However, the mechanistic basis of BTR1 activation by alkaline pH, transport activity regulation and pathogenic mutations remains elusive. Here, we present cryo-EM structures of human BTR1 in the outward-facing state in complex with its activating ligands PIP2 and the inward-facing state with the pathogenic R125H mutation. We reveal that PIP2 binds at the interface between the transmembrane domain and the N-terminal cytosolic domain of BTR1. Disruption of either the PIP2 binding site or protonation of PIP2 phosphate groups by acidic pH can transform BTR1 into an inward-facing conformation. Our results provide insights into the mechanisms of how the transport activity and conformation changes of BTR1 are regulated by PIP2 binding and interaction of TMD and NTD.


Subject(s)
Corneal Dystrophies, Hereditary , Fuchs' Endothelial Dystrophy , Humans , Antiporters/genetics , Fuchs' Endothelial Dystrophy/genetics , Corneal Dystrophies, Hereditary/pathology , Mutation , Protein Domains , Anion Transport Proteins/metabolism
16.
Environ Sci Technol ; 57(34): 12689-12700, 2023 08 29.
Article in English | MEDLINE | ID: mdl-37587658

ABSTRACT

Value chains have played a critical part in the growth. However, the fairness of the social welfare allocation along the value chain is largely underinvestigated, especially when considering the harmful environmental and health effects associated with the production processes. We used fine-scale profiling to analyze the social welfare allocation along China's domestic value chain within the context of environmental and health effects and investigated the underlying mechanisms. Our results suggested that the top 10% regions in the value chain obtained 2.9 times more social income and 2.1 times more job opportunities than the average, with much lower health damage. Further inspection showed a significant contribution of the "siphon effect"─major resource providers suffer the most in terms of localized health damage along with insufficient social welfare for compensation. We found that inter-region atmosphere transport results in redistribution for 53% health damages, which decreases the welfare-damage mismatch at "suffering" regions but also causes serious health damage to more than half of regions and populations in total. Specifically, around 10% of regions have lower social welfare and also experienced a significant increase in health damage caused by atmospheric transport. These results highlighted the necessity of a value chain-oriented, quantitative compensation-driven policy.


Subject(s)
Atmosphere , Policy , China , Particulate Matter
17.
Nat Commun ; 14(1): 3608, 2023 06 17.
Article in English | MEDLINE | ID: mdl-37330603

ABSTRACT

KATP channels are metabolic sensors for intracellular ATP/ADP ratios, play essential roles in many physiological processes, and are implicated in a spectrum of pathological conditions. SUR2A-containing KATP channels differ from other subtypes in their sensitivity to Mg-ADP activation. However, the underlying structural mechanism remains poorly understood. Here we present a series of cryo-EM structures of SUR2A in the presence of different combinations of Mg-nucleotides and the allosteric inhibitor repaglinide. These structures uncover regulatory helix (R helix) on the NBD1-TMD2 linker, which wedges between NBD1 and NBD2. R helix stabilizes SUR2A in the NBD-separated conformation to inhibit channel activation. The competitive binding of Mg-ADP with Mg-ATP to NBD2 mobilizes the R helix to relieve such inhibition, allowing channel activation. The structures of SUR2B in similar conditions suggest that the C-terminal 42 residues of SUR2B enhance the structural dynamics of NBD2 and facilitate the dissociation of the R helix and the binding of Mg-ADP to NBD2, promoting NBD dimerization and subsequent channel activation.


Subject(s)
Potassium Channels, Inwardly Rectifying , Sulfonylurea Receptors/metabolism , Potassium Channels, Inwardly Rectifying/metabolism , Adenosine Triphosphate/metabolism , Adenosine Diphosphate/metabolism , Dimerization , KATP Channels/metabolism
18.
Nucleic Acids Res ; 51(13): 6528-6539, 2023 07 21.
Article in English | MEDLINE | ID: mdl-37247941

ABSTRACT

The nonenzymatic copying of RNA is thought to have been necessary for the transition between prebiotic chemistry and ribozyme-catalyzed RNA replication in the RNA World. We have previously shown that a potentially prebiotic nucleotide activation pathway based on phospho-Passerini chemistry can lead to the efficient synthesis of 2-aminoimidazole activated mononucleotides when carried out under freeze-thaw cycling conditions. Such activated nucleotides react with each other to form 5'-5' 2-aminoimidazolium bridged dinucleotides, enabling template-directed primer extension to occur within the same reaction mixture. However, mononucleotides linked to oligonucleotides by a 5'-5' 2-aminoimidazolium bridge are superior substrates for nonenzymatic primer extension; their higher intrinsic reactivity and their higher template affinity enable faster template copying at lower substrate concentrations. Here we show that eutectic phase phospho-Passerini chemistry efficiently activates short oligonucleotides and promotes the formation of monomer-bridged-oligonucleotide species during freeze-thaw cycles. We then demonstrate that in-situ generated monomer-bridged-oligonucleotides lead to efficient nonenzymatic template copying in the same reaction mixture. Our demonstration that multiple steps in the pathway from activation chemistry to RNA copying can occur together in a single complex environment simplifies this aspect of the origin of life.


The absence of a prebiotically plausible pathway for the efficient nonenzymatic copying of RNAs remains a major obstacle towards constructing self-replicating protocells that emulate early lifeforms. We demonstrate the activation of short oligonucleotides and the subsequent formation of monomer-bridged-oligonucleotide species, leading to efficient nonenzymatic template copying in the same reaction mixture. Our findings suggest that in-situ activated mixtures of mono- and oligo-nucleotides would significantly outperform mononucleotides in driving the copying of arbitrary RNA sequences. Our demonstration that multiple steps in the pathway from activation chemistry to RNA copying can occur together in a single complex environment simplifies this aspect of the origin of life.


Subject(s)
RNA, Catalytic , RNA , RNA/genetics , Oligonucleotides , RNA, Catalytic/metabolism , Nucleotides , Dinucleoside Phosphates
19.
Br J Pharmacol ; 180(18): 2436-2451, 2023 09.
Article in English | MEDLINE | ID: mdl-37143319

ABSTRACT

BACKGROUND AND PURPOSE: Low-grade inflammation, a common feature of both diabetes and periodontitis, partly accounts for the complexity and refractoriness of diabetes-associated periodontitis. Adiponectin (APN), the most abundant adipokine in human blood, has been widely reported to have anti-inflammatory functions. Herein, we investigated the ability of an APN receptor agonist, AdipoAI, to alleviate diabetes-associated periodontitis. Furthermore, we revealed the possible mechanism underlying its anti-inflammatory effects. EXPERIMENTAL APPROACH: The maxillary first molar of Zucker diabetic fatty (ZDF) rats was ligated to construct a diabetes-associated periodontitis model, and rats were administered AdipoAI by gavage. We examined diabetes-related indexes, pathological changes in insulin target organs, alveolar bone resorption and systemic and local inflammation. In vitro, transwell assays were used to evaluate monocyte/macrophage migration induced by human gingival fibroblasts (hGFs) with/without AdipoAI treatment. Additionally, we examined chemokine expression levels in hGFs and hGF-induced monocyte/macrophage migration upon siRNA knockdown of Adiponectin receptor expression. Expression of Adipo1/Adipo2 receptors and inflammation-related signalling pathways were examined by IHC and WB, followed by confirmation with an NF-κB P65 inhibitor (BAY 11-7082). KEY RESULTS: AdipoAI lowered fasting blood glucose and serum insulin in ZDF rats and alleviated inflammation in insulin target tissues. Locally, AdipoAI reduced alveolar bone absorption and gingival inflammation. Mechanistically, AdipoAI inhibited hGF-induced monocyte/macrophage migration by reducing CCL2 secretion. In hGFs, AdipoAI attenuated LPS-induced activation of NF-κB P65 and CCL2 expression, which was dependent on the Adipo receptor 1. CONCLUSION AND IMPLICATIONS: AdipoAI, with its ability to alleviate inflammatory damage in tissues, is a candidate for diabetes-associated periodontitis treatment.


Subject(s)
Alveolar Bone Loss , Diabetes Mellitus, Experimental , Insulins , Periodontitis , Rats , Humans , Animals , Adiponectin/metabolism , Receptors, Adiponectin/metabolism , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Experimental/metabolism , NF-kappa B/metabolism , Rats, Zucker , Periodontitis/drug therapy , Periodontitis/chemically induced , Periodontitis/metabolism , Inflammation/metabolism , Alveolar Bone Loss/drug therapy , Alveolar Bone Loss/prevention & control , Alveolar Bone Loss/metabolism , Macrophages/metabolism , Fibroblasts/metabolism , Insulins/metabolism , Lipopolysaccharides/pharmacology
20.
Environ Sci Technol ; 57(14): 5957-5966, 2023 04 11.
Article in English | MEDLINE | ID: mdl-36994990

ABSTRACT

Organic aerosol (OA) is a key component of fine particulate matter (PM2.5) and affects the human health and leads to climate change. With strict control measures for air pollutants during the last decade, the OA concentration in China declined slowly, while its sources remain unclear. In this study, we simulate the primary OA (POA) and secondary OA (SOA) concentrations from 2005 to 2019 with a state-of-the-art air quality model, Community Multiscale Air Quality (CMAQ, version 5.3.2) coupled with a Two-Dimensional Volatility Basis Set (2D-VBS) module, and a long-term emission inventory of full-volatility organic compounds in China and conduct source apportionment and sensitivity analysis. The simulation results show that, from 2005 to 2019, the OA concentration in China decreased from 24.0 to 12.8 µg/m3 with most of the reduction from POA. The OA pollution from residential biomass burning declined 75% from 2005 to 2019, while it is still the major OA source in China. OA pollution from VCP increased by more than 2-fold and became the largest SOA source in China. From 2014 to 2019, the NOx control in China slightly offset the decrease of SOA concentration due to elevated oxidation capacity.


Subject(s)
Air Pollutants , Environmental Monitoring , Humans , Environmental Monitoring/methods , Air Pollutants/analysis , Particulate Matter/analysis , China , Aerosols/analysis
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