Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 2.642
Filter
Add more filters

Publication year range
1.
Nat Immunol ; 20(10): 1348-1359, 2019 10.
Article in English | MEDLINE | ID: mdl-31406382

ABSTRACT

Helper T cells actively communicate with adjacent cells by secreting soluble mediators, yet crosstalk between helper T cells and endothelial cells remains poorly understood. Here we found that placental growth factor (PlGF), a homolog of the vascular endothelial growth factor that enhances an angiogenic switch in disease, was selectively secreted by the TH17 subset of helper T cells and promoted angiogenesis. Interestingly, the 'angio-lymphokine' PlGF, in turn, specifically induced the differentiation of pathogenic TH17 cells by activating the transcription factor STAT3 via binding to its receptors and replaced the activity of interleukin-6 in the production of interleukin-17, whereas it suppressed the generation of regulatory T cells. Moreover, T cell-derived PlGF was required for the progression of autoimmune diseases associated with TH17 differentiation, including experimental autoimmune encephalomyelitis and collagen-induced arthritis, in mice. Collectively, our findings provide insights into the PlGF-dictated links among angiogenesis, TH17 cell development and autoimmunity.


Subject(s)
Arthritis, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/immunology , Placenta Growth Factor/metabolism , T-Lymphocytes, Regulatory/immunology , Th17 Cells/immunology , Animals , Autoimmunity , Cell Differentiation , Cells, Cultured , Interleukin-17/metabolism , Interleukin-6/metabolism , Lymphocyte Activation , Mice , Mice, Inbred C57BL , Mice, Inbred DBA , Mice, Knockout , Neovascularization, Pathologic , Placenta Growth Factor/genetics , STAT3 Transcription Factor/genetics , STAT3 Transcription Factor/metabolism
2.
Nature ; 633(8030): 594-600, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39294349

ABSTRACT

Climate models indicate that dry extremes will be exacerbated in many regions of the world1,2. However, confidence in the magnitude and timing of these projected changes remains low3,4, leaving societies largely unprepared5,6. Here we show that constraining model projections with observations using a newly proposed emergent constraint (EC) reduces the uncertainty in predictions of a core drought indicator, the longest annual dry spell (LAD), by 10-26% globally. Our EC-corrected projections reveal that the increase in LAD will be 42-44% greater, on average, than 'mid-range' or 'high-end' future forcing scenarios currently indicate. These results imply that by the end of this century, the global mean land-only LAD could be 10 days longer than currently expected. Using two generations of climate models, we further uncover global regions for which historical LAD biases affect the magnitude of projected LAD increases, and we explore the role of land-atmosphere feedbacks therein. Our findings reveal regions with potentially higher- and earlier-than-expected drought risks for societies and ecosystems, and they point to possible mechanisms underlying the biases in the current generation of climate models.


Subject(s)
Climate Models , Droughts , Atmosphere/chemistry , Droughts/statistics & numerical data , Ecosystem , Time Factors , Uncertainty
3.
Proc Natl Acad Sci U S A ; 121(36): e2405138121, 2024 Sep 03.
Article in English | MEDLINE | ID: mdl-39190352

ABSTRACT

The neural pathways that start human color vision begin in the complex synaptic network of the foveal retina where signals originating in long (L), middle (M), and short (S) wavelength-sensitive cone photoreceptor types are compared through antagonistic interactions, referred to as opponency. In nonhuman primates, two cone opponent pathways are well established: an L vs. M cone circuit linked to the midget ganglion cell type, often called the red-green pathway, and an S vs. L + M cone circuit linked to the small bistratified ganglion cell type, often called the blue-yellow pathway. These pathways have been taken to correspond in human vision to cardinal directions in a trichromatic color space, providing the parallel inputs to higher-level color processing. Yet linking cone opponency in the nonhuman primate retina to color mechanisms in human vision has proven particularly difficult. Here, we apply connectomic reconstruction to the human foveal retina to trace parallel excitatory synaptic outputs from the S-ON (or "blue-cone") bipolar cell to the small bistratified cell and two additional ganglion cell types: a large bistratified ganglion cell and a subpopulation of ON-midget ganglion cells, whose synaptic connections suggest a significant and unique role in color vision. These two ganglion cell types are postsynaptic to both S-ON and L vs. M opponent midget bipolar cells and thus define excitatory pathways in the foveal retina that merge the cardinal red-green and blue-yellow circuits, with the potential for trichromatic cone opponency at the first stage of human vision.


Subject(s)
Color Perception , Color Vision , Fovea Centralis , Retinal Cone Photoreceptor Cells , Retinal Ganglion Cells , Humans , Fovea Centralis/physiology , Retinal Cone Photoreceptor Cells/physiology , Retinal Cone Photoreceptor Cells/metabolism , Color Vision/physiology , Retinal Ganglion Cells/physiology , Color Perception/physiology , Retinal Bipolar Cells/physiology , Retinal Bipolar Cells/metabolism , Retina/physiology , Male , Female , Adult , Connectome , Visual Pathways/physiology
4.
Circ Res ; 135(5): e114-e132, 2024 Aug 16.
Article in English | MEDLINE | ID: mdl-38989585

ABSTRACT

BACKGROUND: Atherosclerosis is a chronic inflammatory disease causing a fatal plaque rupture, and its key aspect is a failure to resolve inflammation. We hypothesize that macrophage-targeted near-infrared fluorescence emitting photoactivation could simultaneously assess macrophage/lipid-rich plaques in vivo and facilitate inflammation resolution. METHODS: We fabricated a Dectin-1-targeted photoactivatable theranostic agent through the chemical conjugation of the near-infrared fluorescence-emitting photosensitizer chlorin e6 and the Dectin-1 ligand laminarin (laminarin-chlorin e6 [LAM-Ce6]). Intravascular photoactivation by a customized fiber-based diffuser after administration of LAM-Ce6 effectively reduced inflammation in the targeted plaques of atherosclerotic rabbits in vivo as serially assessed by dual-modal optical coherence tomography-near-infrared fluorescence structural-molecular catheter imaging after 4 weeks. RESULTS: The number of apoptotic macrophages peaked at 1 day after laser irradiation and then resolved until 4 weeks. Autophagy was strongly augmented 1 hour after the light therapy, with the formation of autophagolysosomes. LAM-Ce6 photoactivation increased the terminal deoxynucleotidyl transferase dUTP (deoxyuridine triphosphate) nick end labeling/RAM11 (rabbit monocyte/macrophage antibody)- and MerTK (c-Mer tyrosine kinase)-positive cells in the plaques, suggesting enhanced efferocytosis. In line with inflammation resolution, photoactivation reduced the plaque burden through fibrotic replacement via the TGF (transforming growth factor)-ß/CTGF (connective tissue growth factor) pathway. CONCLUSIONS: Optical coherence tomography-near-infrared fluorescence imaging-guided macrophage Dectin-1-targetable photoactivation could induce the transition of macrophage/lipid-rich plaques into collagen-rich lesions through autophagy-mediated inflammation resolution and TGF-ß-dependent fibrotic replacement. This novel strategy offers a new opportunity for the catheter-based theranostic strategy.


Subject(s)
Chlorophyllides , Multimodal Imaging , Photosensitizing Agents , Plaque, Atherosclerotic , Porphyrins , Tomography, Optical Coherence , Animals , Plaque, Atherosclerotic/diagnostic imaging , Rabbits , Multimodal Imaging/methods , Tomography, Optical Coherence/methods , Photosensitizing Agents/pharmacology , Photosensitizing Agents/therapeutic use , Macrophages/metabolism , Theranostic Nanomedicine/methods , Mice , Male , Autophagy , c-Mer Tyrosine Kinase/metabolism , Apoptosis
5.
EMBO Rep ; 25(10): 4281-4310, 2024 Oct.
Article in English | MEDLINE | ID: mdl-39191946

ABSTRACT

Aberrant mitochondrial fission/fusion dynamics are frequently associated with pathologies, including cancer. We show that alternative splice variants of the fission protein Drp1 (DNM1L) contribute to the complexity of mitochondrial fission/fusion regulation in tumor cells. High tumor expression of the Drp1 alternative splice variant lacking exon 16 relative to other transcripts is associated with poor outcome in ovarian cancer patients. Lack of exon 16 results in Drp1 localization to microtubules and decreased association with mitochondrial fission sites, culminating in fused mitochondrial networks, enhanced respiration, changes in metabolism, and enhanced pro-tumorigenic phenotypes in vitro and in vivo. These effects are inhibited by siRNAs designed to specifically target the endogenously expressed transcript lacking exon 16. Moreover, lack of exon 16 abrogates mitochondrial fission in response to pro-apoptotic stimuli and leads to decreased sensitivity to chemotherapeutics. These data emphasize the pathophysiological importance of Drp1 alternative splicing, highlight the divergent functions and consequences of changing the relative expression of Drp1 splice variants in tumor cells, and strongly warrant consideration of alternative splicing in future studies focused on Drp1.


Subject(s)
Alternative Splicing , Dynamins , GTP Phosphohydrolases , Microtubule-Associated Proteins , Mitochondria , Mitochondrial Dynamics , Mitochondrial Proteins , Ovarian Neoplasms , Humans , Dynamins/genetics , Dynamins/metabolism , Mitochondrial Dynamics/genetics , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Ovarian Neoplasms/metabolism , Female , Microtubule-Associated Proteins/genetics , Microtubule-Associated Proteins/metabolism , Cell Line, Tumor , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , GTP Phosphohydrolases/genetics , GTP Phosphohydrolases/metabolism , Mitochondria/metabolism , Mitochondria/genetics , Animals , Disease Progression , Exons/genetics , Mice , Gene Expression Regulation, Neoplastic , Protein Isoforms/genetics , Protein Isoforms/metabolism , Microtubules/metabolism , Apoptosis/genetics
6.
Proc Natl Acad Sci U S A ; 120(18): e2300545120, 2023 05 02.
Article in English | MEDLINE | ID: mdl-37098066

ABSTRACT

The Old World macaque monkey and New World common marmoset provide fundamental models for human visual processing, yet the human ancestral lineage diverged from these monkey lineages over 25 Mya. We therefore asked whether fine-scale synaptic wiring in the nervous system is preserved across these three primate families, despite long periods of independent evolution. We applied connectomic electron microscopy to the specialized foveal retina where circuits for highest acuity and color vision reside. Synaptic motifs arising from the cone photoreceptor type sensitive to short (S) wavelengths and associated with "blue-yellow" (S-ON and S-OFF) color-coding circuitry were reconstructed. We found that distinctive circuitry arises from S cones for each of the three species. The S cones contacted neighboring L and M (long- and middle-wavelength sensitive) cones in humans, but such contacts were rare or absent in macaques and marmosets. We discovered a major S-OFF pathway in the human retina and established its absence in marmosets. Further, the S-ON and S-OFF chromatic pathways make excitatory-type synaptic contacts with L and M cone types in humans, but not in macaques or marmosets. Our results predict that early-stage chromatic signals are distinct in the human retina and imply that solving the human connectome at the nanoscale level of synaptic wiring will be critical for fully understanding the neural basis of human color vision.


Subject(s)
Color Vision , Connectome , Animals , Humans , Callithrix , Color Perception/physiology , Retina/physiology , Retinal Cone Photoreceptor Cells/physiology , Macaca , Cercopithecidae
7.
Proc Natl Acad Sci U S A ; 120(20): e2302937120, 2023 05 16.
Article in English | MEDLINE | ID: mdl-37155852

ABSTRACT

Implantation is the first direct encounter between the embryo and uterus during pregnancy, and Hbegf is the earliest known molecular signaling for embryo-uterine crosstalk during implantation. The downstream effectors of heparin-binding EGF (HB-EGF) in implantation remain elusive due to the complexity of EGF receptor family. This study shows that the formation of implantation chamber (crypt) triggered by HB-EGF is disrupted by uterine deletion of Vangl2, a key planar cell polarity component (PCP). We found that HB-EGF binds to ERBB2 and ERBB3 to recruit VANGL2 for tyrosine phosphorylation. Using in vivo models, we show that uterine VAGL2 tyrosine phosphorylation is suppressed in Erbb2/Erbb3 double conditional knockout mice. In this context, severe implantation defects in these mice lend support to the critical role of HB-EGF-ERBB2/3-VANGL2 in establishing a two-way dialogue between the blastocyst and uterus. In addition, the result addresses an outstanding question how VANGL2 is activated during implantation. Taken together, these observations reveal that HB-EGF regulates the implantation process by influencing uterine epithelial cell polarity comprising VANGL2.


Subject(s)
Cell Polarity , Embryo Implantation , Animals , Female , Mice , Pregnancy , Cell Polarity/physiology , Embryo Implantation/physiology , Heparin-binding EGF-like Growth Factor/genetics , Heparin-binding EGF-like Growth Factor/metabolism , Mice, Knockout , Signal Transduction , Tyrosine
8.
EMBO J ; 40(24): e108684, 2021 12 15.
Article in English | MEDLINE | ID: mdl-34726281

ABSTRACT

Plant photoperiodic growth is coordinated by interactions between circadian clock and light signaling networks. How post-translational modifications of clock proteins affect these interactions to mediate rhythmic growth remains unclear. Here, we identify five phosphorylation sites in the Arabidopsis core clock protein TIMING OF CAB EXPRESSION 1 (TOC1) which when mutated to alanine eliminate detectable phosphorylation. The TOC1 phospho-mutant fails to fully rescue the clock, growth, and flowering phenotypes of the toc1 mutant. Further, the TOC1 phospho-mutant shows advanced phase, a faster degradation rate, reduced interactions with PHYTOCHROME-INTERACTING FACTOR 3 (PIF3) and HISTONE DEACETYLASE 15 (HDA15), and poor binding at pre-dawn hypocotyl growth-related genes (PHGs), leading to a net de-repression of hypocotyl growth. NUCLEAR FACTOR Y subunits B and C (NF-YB/C) stabilize TOC1 at target promoters, and this novel trimeric complex (NF-TOC1) acts as a transcriptional co-repressor with HDA15 to inhibit PIF-mediated hypocotyl elongation. Collectively, we identify a molecular mechanism suggesting how phosphorylation of TOC1 alters its phase, stability, and physical interactions with co-regulators to precisely phase PHG expression to control photoperiodic hypocotyl growth.


Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/growth & development , CCAAT-Binding Factor/metabolism , Mutation , Transcription Factors/genetics , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Gene Expression Regulation, Plant , Histone Deacetylases/metabolism , Hypocotyl/growth & development , Hypocotyl/metabolism , Phosphorylation , Proteolysis , Signal Transduction , Transcription Factors/chemistry , Transcription Factors/metabolism
9.
J Immunol ; 210(11): 1687-1699, 2023 06 01.
Article in English | MEDLINE | ID: mdl-37042681

ABSTRACT

Although CD4+CD25+FOXP3+ regulatory T (TREG) cells have been studied in patients with COVID-19, changes in the TREG cell population have not been longitudinally examined during the course of COVID-19. In this study, we longitudinally investigated the quantitative and qualitative changes in the TREG cell population in patients with COVID-19. We found that the frequencies of total TREG cells and CD45RA-FOXP3hi activated TREG cells were significantly increased 15-28 d postsymptom onset in severe patients, but not in mild patients. TREG cells from severe patients exhibited not only increased proliferation but also enhanced apoptosis, suggesting functional derangement of the TREG cell population during severe COVID-19. The suppressive functions of the TREG cell population did not differ between patients with severe versus mild COVID-19. The frequency of TREG cells inversely correlated with SARS-CoV-2-specific cytokine production by CD4+ T cells and their polyfunctionality in patients with mild disease, suggesting that TREG cells are major regulators of virus-specific CD4+ T cell responses during mild COVID-19. However, such correlations were not observed in patients with severe disease. Thus, in this study, we describe distinctive changes in the TREG cell population in patients with severe and mild COVID-19. Our study provides a deep understanding of host immune responses upon SARS-CoV-2 infection in regard to TREG cells.


Subject(s)
COVID-19 , T-Lymphocytes, Regulatory , Humans , SARS-CoV-2 , CD4-Positive T-Lymphocytes , Interleukin-2 Receptor alpha Subunit , Forkhead Transcription Factors
10.
J Immunol ; 210(12): 1974-1989, 2023 Jun 15.
Article in English | MEDLINE | ID: mdl-37163338

ABSTRACT

The gasdermins are a family of pore-forming proteins that has recently been suggested to play a central role in pyroptosis. In this study, we describe the novel roles of gasdermins in the biogenesis of apoptotic cell-derived exosomes. In apoptotic human HeLa and HEK293 cells, GSDMA, GSDMC, GSDMD, and GSDME increased the release of apoptotic exosomes. GSDMB and DFNB59, in contrast, negatively affected the release of apoptotic exosomes. GSDME at its full-length and cleaved forms was localized in the exosomes and exosomal membrane. Full-length and cleaved forms of GSDME are suggested to increase Ca2+ influx to the cytosol through endosomal pores and thus increase the biogenesis of apoptotic exosomes. In addition, the GSDME-mediated biogenesis of apoptotic exosomes depended on the ESCRT-III complex and endosomal recruitment of Ca2+-dependent proteins, that is, annexins A2 and A7, the PEF domain family proteins sorcin and grancalcin, and the Bro1 domain protein HD-PTP. Therefore, we propose that the biogenesis of apoptotic exosomes begins when gasdermin-mediated endosomal pores increase cytosolic Ca2+, continues through the recruitment of annexin-sorcin/grancalcin-HD-PTP, and is completed when the ESCRT-III complex synthesizes intraluminal vesicles in the multivesicular bodies of dying cells. Finally, we found that GSDME-bearing tumors released apoptotic exosomes to induce inflammatory responses in the in vivo mouse 4T1 orthotropic model of BALB/c breast cancer. The data indicate that the switch from apoptosis to pyroptosis could drive the transfer of mass signals to nearby or distant living cells and tissues by way of extracellular vesicles, and that gasdermins play critical roles in that process.

11.
Proc Natl Acad Sci U S A ; 119(51): e2203711119, 2022 12 20.
Article in English | MEDLINE | ID: mdl-36512497

ABSTRACT

The selenium-binding protein 1 (SELENBP1) has been reported to be up-regulated in the prefrontal cortex (PFC) of schizophrenia patients in postmortem reports. However, no causative link between SELENBP1 and schizophrenia has yet been established. Here, we provide evidence linking the upregulation of SELENBP1 in the PFC of mice with the negative symptoms of schizophrenia. We verified the levels of SELENBP1 transcripts in postmortem PFC brain tissues from patients with schizophrenia and matched healthy controls. We also generated transgenic mice expressing human SELENBP1 (hSELENBP1 Tg) and examined their neuropathological features, intrinsic firing properties of PFC 2/3-layer pyramidal neurons, and frontal cortex (FC) electroencephalographic (EEG) responses to auditory stimuli. Schizophrenia-like behaviors in hSELENBP1 Tg mice and mice expressing Selenbp1 in the FC were assessed. SELENBP1 transcript levels were higher in the brains of patients with schizophrenia than in those of matched healthy controls. The hSELENBP1 Tg mice displayed negative endophenotype behaviors, including heterotopias- and ectopias-like anatomical deformities in upper-layer cortical neurons and social withdrawal, deficits in nesting, and anhedonia-like behavior. Additionally, hSELENBP1 Tg mice exhibited reduced excitabilities of PFC 2/3-layer pyramidal neurons and abnormalities in EEG biomarkers observed in schizophrenia. Furthermore, mice overexpressing Selenbp1 in FC showed deficits in sociability. These results suggest that upregulation of SELENBP1 in the PFC causes asociality, a negative symptom of schizophrenia.


Subject(s)
Schizophrenia , Humans , Animals , Mice , Schizophrenia/genetics , Schizophrenia/metabolism , Prefrontal Cortex/metabolism , Pyramidal Cells/metabolism , Brain/metabolism , Mice, Transgenic , Selenium-Binding Proteins/genetics , Selenium-Binding Proteins/metabolism
12.
Proc Natl Acad Sci U S A ; 119(30): e2119048119, 2022 07 26.
Article in English | MEDLINE | ID: mdl-35858411

ABSTRACT

The major challenges in pancreatic ductal adenocarcinoma (PDAC) management are local or distant metastasis and limited targeted therapeutics to prevent it. To identify a druggable target in tumor secretome and to explore its therapeutic intervention, we performed a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic analysis of tumors obtained from a patient-derived xenograft model of PDAC. Galectin-3 binding protein (Gal-3BP) is identified as a highly secreted protein, and its overexpression is further validated in multiple PDAC tumors and primary cells. Knockdown and exogenous treatment of Gal-3BP showed that it is required for PDAC cell proliferation, migration, and invasion. Mechanistically, we revealed that Gal-3BP enhances galectin-3-mediated epidermal growth factor receptor signaling, leading to increased cMyc and epithelial-mesenchymal transition. To explore the clinical impact of these findings, two antibody clones were developed, and they profoundly abrogated the metastasis of PDAC cells in vivo. Altogether, our data demonstrate that Gal-3BP is an important therapeutic target in PDAC, and we propose its blockade by antibody as a therapeutic option for suppressing PDAC metastasis.


Subject(s)
Antigens, Neoplasm , Antineoplastic Agents, Immunological , Biomarkers, Tumor , Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Animals , Antigens, Neoplasm/genetics , Antigens, Neoplasm/immunology , Antineoplastic Agents, Immunological/immunology , Antineoplastic Agents, Immunological/therapeutic use , Biomarkers, Tumor/antagonists & inhibitors , Biomarkers, Tumor/genetics , Biomarkers, Tumor/immunology , Carcinoma, Pancreatic Ductal/genetics , Carcinoma, Pancreatic Ductal/secondary , Carcinoma, Pancreatic Ductal/therapy , Cell Line, Tumor , Cell Movement , Cell Proliferation , Chromatography, Liquid , Epithelial-Mesenchymal Transition , Gene Knockdown Techniques , Humans , Mice , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/therapy , Proteomics , Secretome , Tandem Mass Spectrometry , Xenograft Model Antitumor Assays
13.
Nano Lett ; 24(19): 5855-5861, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38690800

ABSTRACT

Quantum dots (QDs) have garnered a significant amount of attention as promising memristive materials owing to their size-dependent tunable bandgap, structural stability, and high level of applicability for neuromorphic computing. Despite these advantageous properties, the development of QD-based memristors has been hindered by challenges in understanding and adjusting the resistive switching (RS) behavior of QDs. Herein, we propose three types of InP/ZnSe/ZnS QD-based memristors to elucidate the RS mechanism, employing a thin poly(methyl methacrylate) layer. This approach not only allows us to identify which carriers (electron or hole) are trapped within the QD layer but also successfully demonstrates QD-based synaptic devices. Furthermore, to utilize the QD memristor as a synapse, long-term potentiation/depression (LTP/LTD) characteristics are measured, resulting in a low nonlinearity of LTP/LTD at 0.1/1. On the basis of the LTP/LTD characteristics, single-layer perceptron simulations were performed using the Extended Modified National Institute of Standards and Technology, verifying a maximum recognition rate of 91.46%.

14.
J Am Chem Soc ; 146(33): 23067-23074, 2024 Aug 21.
Article in English | MEDLINE | ID: mdl-39134028

ABSTRACT

A new class of Ru-sulfonamidate precatalysts for sp3 C-H hydroxylation is described along with a versatile process for assembling unique heteroleptic Ru(II) complexes. The latter has enabled structure-performance studies to identify an optimal precatalyst, 2h, bearing one 4,4'-di-tert-butylbipyridine (dtbpy) and one pyridylsulfonamidate ligand. Single-crystal X-ray analysis confirmed the structure and stereochemistry of this adduct. Catalytic hydroxylation reactions are conveniently performed in an aqueous, biphasic solvent mixture with 1 mol % 2h and ceric ammonium nitrate as the terminal oxidant and deliver oxidized products in yields ranging from 37 to 90%. A comparative mechanistic investigation of 2h against a related homoleptic precatalyst, [Ru(dtbpy)2(MeCN)2](OTf)2, convincingly establishes that the former generates one or more surprisingly long-lived active species under the reaction conditions, thus accounting for the high turnover numbers. Structure-performance, kinetics, mass spectrometric, and electrochemical analyses reveal that ligand oxidation is a prerequisite for catalyst activation. Our findings sharply contrast a large body of prior art showing that ligand oxidation is detrimental to catalyst function. We expect these results to stimulate future innovations in C-H oxidation research.

15.
J Am Chem Soc ; 146(5): 3521-3530, 2024 Feb 07.
Article in English | MEDLINE | ID: mdl-38284769

ABSTRACT

Copper-catalyzed aerobic oxidative coupling of diaryl imines provides a route for conversion of ammonia to hydrazine. The present study uses experimental and density functional theory computational methods to investigate the mechanism of N-N bond formation, and the data support a mechanism involving bimolecular coupling of Cu-coordinated iminyl radicals. Computational analysis is extended to CuII-mediated C-C, N-N, and O-O coupling reactions involved in the formation of cyanogen (NC-CN) from HCN, 1,3-butadiyne from ethyne (i.e., Glaser coupling), hydrazine from ammonia, and hydrogen peroxide from water. The results reveal two different mechanistic pathways. Heteroatom ligands with an uncoordinated lone pair (iminyl, NH2, OH) undergo charge transfer to CuII, generating ligand-centered radicals that undergo facile bimolecular radical-radical coupling. Ligands lacking a lone pair (CN and CCH) form bridged binuclear diamond-core structures that undergo C-C coupling. This mechanistic bifurcation is rationalized by analysis of spin densities in key intermediates and transition states, as well as multiconfigurational calculations. Radical-radical coupling is especially favorable for N-N coupling owing to energetically favorable charge transfer in the intermediate and thermodynamically favorable product formation.

16.
Emerg Infect Dis ; 30(5): 991-994, 2024 May.
Article in English | MEDLINE | ID: mdl-38666642

ABSTRACT

African swine fever virus (ASFV) genotype II is endemic to Vietnam. We detected recombinant ASFV genotypes I and II (rASFV I/II) strains in domestic pigs from 6 northern provinces in Vietnam. The introduction of rASFV I/II strains could complicate ongoing ASFV control measures in the region.


Subject(s)
African Swine Fever Virus , African Swine Fever , Genotype , Phylogeny , Animals , African Swine Fever Virus/genetics , African Swine Fever Virus/classification , Vietnam/epidemiology , African Swine Fever/epidemiology , African Swine Fever/virology , Swine , Sus scrofa/virology , Recombination, Genetic
17.
BMC Biotechnol ; 24(1): 67, 2024 Sep 27.
Article in English | MEDLINE | ID: mdl-39334326

ABSTRACT

Adenoviruses are commonly utilized as viral vectors for gene therapy, genetic vaccines, and recombinant protein expression. To generate replication-defective adenoviruses, E1-complementing cell lines such as HEK293A are utilized; however, limitations remain. Repeated passage of E1-deleted virus in HEK293A cells increases the occurrence of replication-competent adenoviruses (RCAs). In the present study, we developed a novel cell line originating from human primary cells. L132 cells were transduced two times with E1-encoded retrovirus and three times with E1A-encoded retrovirus. Finally, we selected the most productive L132 cell line for generation of RCA-free adenovirus, GT541. GT541 can serve as an alternative cell line to HEK293A and other adenovirus-producing cells.


Subject(s)
Adenoviridae , Virus Replication , Humans , HEK293 Cells , Adenoviridae/genetics , Adenoviridae/physiology , Genetic Vectors/genetics , Cell Line
18.
HIV Med ; 25(3): 381-390, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38147871

ABSTRACT

OBJECTIVES: Cabotegravir + rilpivirine (CAB + RPV) dosed monthly or every 2 months is the first complete long-acting (LA) regimen recommended by treatment guidelines for the maintenance of HIV-1 virological suppression. This post hoc analysis summarizes outcomes for Asian participants through week 96. METHODS: Data from Asian participants naive to CAB + RPV randomized to receive dosing every 4 weeks (Q4W) or every 8 weeks (Q8W) in the FLAIR (NCT02938520) and ATLAS-2M (NCT03299049) phase 3/3b studies were pooled. The proportion of participants with plasma HIV-1 RNA ≥50 and <50 copies/mL (per FDA Snapshot algorithm), incidence of confirmed virological failure (CVF; two consecutive HIV-1 RNA ≥200 copies/mL), pharmacokinetics, safety, and tolerability through week 96 were assessed. RESULTS: Overall, 41 Asian participants received CAB + RPV (Q8W, n = 17; Q4W, n = 24). At week 96, 83% (n = 34/41) of participants maintained HIV-1 RNA <50 copies/mL, none had HIV-1 RNA ≥50 copies/mL, and 17% (n = 7/41) had no virological data. No Asian participant met the CVF criterion. Drug-related adverse events occurred in 44% (n = 18/41) of participants; none were Grade ≥3. All injection site reactions were Grade 1 or 2; median duration was 2 days and most resolved within 7 days (90%, n = 390/435). CAB and RPV trough concentrations remained well above their respective protein-adjusted 90% inhibitory concentrations (CAB, 0.166 µg/mL; RPV, 12 ng/mL) through week 96. CONCLUSIONS: CAB + RPV LA demonstrated high efficacy, with no participants having CVF, and an acceptable safety profile in Asian participants through week 96. These data support CAB + RPV LA as a complete regimen for the maintenance of HIV-1 virological suppression in Asian individuals.


Subject(s)
Anti-HIV Agents , Diketopiperazines , HIV Infections , HIV Seropositivity , Pyridones , Humans , Anti-HIV Agents/adverse effects , HIV Infections/drug therapy , HIV Seropositivity/drug therapy , Rilpivirine , RNA, Viral , Clinical Trials, Phase III as Topic , Randomized Controlled Trials as Topic
19.
New Phytol ; 244(3): 798-810, 2024 Nov.
Article in English | MEDLINE | ID: mdl-39155726

ABSTRACT

Arabidopsis PSEUDORESPONSE REGULATOR7 (PRR7) is a core component of the circadian oscillator which also plays a crucial role in freezing tolerance. PRR7 undergoes proteasome-dependent degradation to discretely phase maximal expression in early evening. While its repressive activity on downstream genes is integral to cold regulation, the mechanism of the conditional regulation of the PRR7 abundance is unknown. We used mutant analysis, protein interaction and ubiquitylation assays to establish that the ubiquitin ligase adaptor, HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE 15 (HOS15), controls the protein accumulation pattern of PRR7 through direct protein-protein interactions at low temperatures. Freezing tolerance and electrolyte leakage assays show that PRR7 enhances cold temperature sensitivity, supported by ChIP-qPCR at C-REPEAT BINDING FACTOR1 (CBF1) and COLD-REGULATED 15A (COR15A) promoters where PRR7 levels were higher in hos15 mutants. HOS15 mediates PRR7 turnover through enhanced ubiquitylation at low temperature in the dark. Under the same conditions, increased PRR7 association with the promoters of CBFs and COR15A in hos15 correlates with decreased CBF1 and COR15A transcription and enhanced freezing sensitivity. We propose a novel mechanism whereby HOS15-mediated degradation of PRR7 provides an intersection between the circadian system and other cold acclimation pathways that lead to increased freezing tolerance.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Freezing , Gene Expression Regulation, Plant , Mutation , Transcription Factors , Ubiquitination , Arabidopsis Proteins/metabolism , Arabidopsis Proteins/genetics , Arabidopsis/genetics , Arabidopsis/physiology , Arabidopsis/metabolism , Transcription Factors/metabolism , Transcription Factors/genetics , Mutation/genetics , Promoter Regions, Genetic/genetics , Adaptation, Physiological/genetics , Protein Binding , Proteolysis , Repressor Proteins
20.
Cytokine ; 178: 156579, 2024 06.
Article in English | MEDLINE | ID: mdl-38471419

ABSTRACT

The aim of this study was to evaluate the effect of non-surgical periodontal treatment in the expression of chemokine receptors, in individuals with Periodontitis, associated or not with Diabetes. Pilot study, which included patients (n = 45) with Periodontitis, associated (n = 25) or not (n = 20) with Diabetes, submitted to the non-surgical periodontal treatment for one month. The expression of chemokine receptors CCR2, CCR5, and CX3CR1 at the mRNA level was evaluated in the peripheral mononuclear cells, as well as the expression of these receptors at the protein level was verified in monocyte subtypes (classical, intermediate, and non-classical monocytes). There was higher expression of CCR2 and CCR5 receptors at the initial visit in the group with Diabetes, with no differences for CX3CR1 (p = 0.002; p = 0.018, and p = 0.896, respectively), without differences after treatment. There was higher expression of CCR2 and CCR5 proteins in the group with Diabetes at the initial visit for classical, intermediate, and nonclassical monocytes, with no differences for CX3CR1 (CCR2: p = 0.004; p = 0.026; p = 0.024; CCR5: 0.045; p = 0.045; p = 0.013; CX3CR1: p = 0.424; p = 0.944; p = 0.392, respectively), without differences after the end of treatment. Concerning each group separately, there were reductions in the expression of CCR2 as well as CCR5 in classical, intermediate, and nonclassical monocytes, and reduction of CX3CR1 in classical monocytes after treatment in the group with Diabetes (p = 0.003; p = 0.006; p = 0.039; p = 0.007; p = 0.006; p = 0.004; p = 0.019, respectively), without differences in the group without Diabetes. The expression of the chemokine receptors CCR2 and CCR5, in patients with Periodontitis associated with Diabetes, is favorably modified after the end of the non-surgical periodontal treatment.


Subject(s)
Diabetes Mellitus , Periodontitis , Humans , Monocytes/metabolism , Pilot Projects , Receptors, CCR2/genetics , Receptors, CCR2/metabolism , Receptors, CCR5/genetics , Receptors, CCR5/metabolism , Diabetes Mellitus/metabolism , Periodontitis/therapy , Periodontitis/metabolism , CX3C Chemokine Receptor 1/genetics , CX3C Chemokine Receptor 1/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL