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1.
PLoS Pathog ; 19(6): e1011464, 2023 06.
Article in English | MEDLINE | ID: mdl-37379354

ABSTRACT

Human papillomaviruses (HPV) cause persistent infections by modulating epithelial homeostasis in cells of the infected basal layer. Using FUCCI and cell-cell competition assays, we have identifed regulatory roles for E6AP and NHERF1, which are the primary HPV11 E6 cellular targets, as well as being targets of the high-risk E6 proteins, in processes governing epithelial homeostasis (i.e. cell density, cell cycle entry, commitment to differentiation and basal layer delamination). Depletion of E6AP, or expression of HPV11 or 16E6 increased keratinocyte cell density and cell cycle activity, and delayed the onset of differentiation; phenotypes which were conspicuously present in HPV11 and 16 infected patient tissue. In line with proposed E6 functions, in HPV11 condyloma tissue, E6AP and NHERF1 were significantly reduced when compared to uninfected epithelium. In experimental systems, loss of HPV11 E6/E6AP binding abolished 11E6's homeostasis regulatory functions, while loss of E6/NHERF1 binding reduced the cell density threshold at which differentiation was triggered. By contrast, a NHERF1-binding mutant of 16E6 was not compromised in its homeostasis functions, while E6AP appeared essential. RNA sequencing revealed similar transcriptional profiles in both 11 and 16E6-expressing cells and E6AP-/- cells, with YAP target genes induced, and keratinocyte differentiation genes being downregulated. HPV11 E6-mediated Yap activation was observed in 2D and 3D (organotypic raft) cell culture systems and HPV-infected lesions, with both NHERF1, which is a regulator of the Hippo and Wnt pathways, and E6AP, playing an important role. As the conserved binding partner of Alpha group HPV E6 proteins, the precise role of E6AP in modulating keratinocyte phenotype and associated signalling pathways has not previously been defined. Our study suggests a model in which the preserved functions of the low and high-risk Alpha E6 proteins modulate epithelial homeostasis via E6AP activity, and lead to alteration of multiple downstream pathways, including those involving NHERF1 and YAP.


Subject(s)
Oncogene Proteins, Viral , Papillomavirus Infections , Humans , Human Papillomavirus Viruses , Repressor Proteins/metabolism , Ubiquitin-Protein Ligases/metabolism , Papillomaviridae/genetics , Oncogene Proteins, Viral/genetics , Oncogene Proteins, Viral/metabolism , Cell Differentiation , Keratinocytes , Homeostasis
2.
Proc Natl Acad Sci U S A ; 119(6)2022 02 08.
Article in English | MEDLINE | ID: mdl-35105806

ABSTRACT

The protumor roles of alternatively activated (M2) tumor-associated macrophages (TAMs) have been well established, and macrophage reprogramming is an important therapeutic goal. However, the mechanisms of TAM polarization remain incompletely understood, and effective strategies for macrophage targeting are lacking. Here, we show that miR-182 in macrophages mediates tumor-induced M2 polarization and can be targeted for therapeutic macrophage reprogramming. Constitutive miR-182 knockout in host mice and conditional knockout in macrophages impair M2-like TAMs and breast tumor development. Targeted depletion of macrophages in mice blocks the effect of miR-182 deficiency in tumor progression while reconstitution of miR-182-expressing macrophages promotes tumor growth. Mechanistically, cancer cells induce miR-182 expression in macrophages by TGFß signaling, and miR-182 directly suppresses TLR4, leading to NFκb inactivation and M2 polarization of TAMs. Importantly, therapeutic delivery of antagomiR-182 with cationized mannan-modified extracellular vesicles effectively targets macrophages, leading to miR-182 inhibition, macrophage reprogramming, and tumor suppression in multiple breast cancer models of mice. Overall, our findings reveal a crucial TGFß/miR-182/TLR4 axis for TAM polarization and provide rationale for RNA-based therapeutics of TAM targeting in cancer.


Subject(s)
Cellular Reprogramming , Mammary Neoplasms, Animal/metabolism , MicroRNAs/metabolism , RNA, Neoplasm/metabolism , Signal Transduction , Tumor-Associated Macrophages/metabolism , Animals , Female , Gene Expression Regulation, Neoplastic , HeLa Cells , Humans , Mammary Neoplasms, Animal/genetics , Mice , Mice, Knockout , MicroRNAs/genetics , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , RNA, Neoplasm/genetics , Toll-Like Receptor 4/biosynthesis , Toll-Like Receptor 4/genetics , Transforming Growth Factor beta/biosynthesis , Transforming Growth Factor beta/genetics
3.
J Med Virol ; 95(6): e28834, 2023 06.
Article in English | MEDLINE | ID: mdl-37254637

ABSTRACT

Persistent high-risk human papilloma virus (HR-HPV) infection is the main risk factor for cervical cancer, threatening women's health. Despite growing prophylactic vaccination, annual cervical cancer cases are still increasing and show a trend of younger onset age. However, therapeutic approaches towards HPV infection are still limited. 25-hydrocholesterol (25HC) has a wide-spectrum inhibitory effect on a variety of viruses. To explore efficient interventions to restrict HPV infection at an early time, we applied different pseudoviruses (PsV) to evaluate anti-HPV efficacy of 25HC. We tested PsV inhibition by 25HC in cervical epithelial-derived HeLa and C-33A cells, using high-risk (HPV16, HPV18, HPV59), possibly carcinogenic (HPV73), and low-risk (HPV6) HPV PsVs. Then we established murine genital HPV PsV infection models and applied IVIS to evaluate anti-HPV efficacy of 25HC in vivo. Next, with the help of confocal imaging, we targeted 25HC activity at filopodia upon HPV exposure. After that, we used RNA-seq and Western blot analysis to investigate (1) how 25HC disturbs actin cytoskeleton remodeling during HPV infection and (2) how prenylation regulates the cytoskeletal remodeling signaling pathway. Our findings suggest that 25HC perturbs F-actin rearrangement by reducing small GTPase prenylation. In this way, the phenomenon of HPV virion surfing was restricted, leading to failed infection.


Subject(s)
Papillomavirus Infections , Uterine Cervical Neoplasms , Humans , Female , Animals , Mice , Human Papillomavirus Viruses , Epithelial Cells
4.
Fa Yi Xue Za Zhi ; 39(1): 57-65, 2023 Feb 25.
Article in English, Zh | MEDLINE | ID: mdl-37038857

ABSTRACT

Lung is the largest organ of the respiratory system. During hypoxia, pulmonary cells undergo rapid damage changes and activate the self-rescue pathways, thus leading to complex biomacromolecule modification. Death from mechanical asphyxia refers to death due to acute respiratory disorder caused by mechanical violence. Because of the absence of characteristic signs in corpse, the accurate identification of mechanical asphyxia has always been the difficulty in forensic pathology. This paper reviews the biomacromolecule changes under the pulmonary hypoxia condition and discusses the possibility of application of these changes to accurate identification of death from mechanical asphyxia, aiming to provide new ideas for related research.


Subject(s)
Asphyxia , Hypoxia , Humans , Asphyxia/etiology , Asphyxia/pathology , Cause of Death , Hypoxia/pathology , Lung/pathology , Forensic Pathology
5.
Int J Mol Sci ; 22(9)2021 May 10.
Article in English | MEDLINE | ID: mdl-34068835

ABSTRACT

Molecular modeling is widely utilized in subjects including but not limited to physics, chemistry, biology, materials science and engineering. Impressive progress has been made in development of theories, algorithms and software packages. To divide and conquer, and to cache intermediate results have been long standing principles in development of algorithms. Not surprisingly, most important methodological advancements in more than half century of molecular modeling are various implementations of these two fundamental principles. In the mainstream classical computational molecular science, tremendous efforts have been invested on two lines of algorithm development. The first is coarse graining, which is to represent multiple basic particles in higher resolution modeling as a single larger and softer particle in lower resolution counterpart, with resulting force fields of partial transferability at the expense of some information loss. The second is enhanced sampling, which realizes "dividing and conquering" and/or "caching" in configurational space with focus either on reaction coordinates and collective variables as in metadynamics and related algorithms, or on the transition matrix and state discretization as in Markov state models. For this line of algorithms, spatial resolution is maintained but results are not transferable. Deep learning has been utilized to realize more efficient and accurate ways of "dividing and conquering" and "caching" along these two lines of algorithmic research. We proposed and demonstrated the local free energy landscape approach, a new framework for classical computational molecular science. This framework is based on a third class of algorithm that facilitates molecular modeling through partially transferable in resolution "caching" of distributions for local clusters of molecular degrees of freedom. Differences, connections and potential interactions among these three algorithmic directions are discussed, with the hope to stimulate development of more elegant, efficient and reliable formulations and algorithms for "dividing and conquering" and "caching" in complex molecular systems.


Subject(s)
Models, Molecular , Molecular Dynamics Simulation , Algorithms , Thermodynamics
6.
Molecules ; 25(11)2020 Jun 08.
Article in English | MEDLINE | ID: mdl-32521606

ABSTRACT

The cooperative binding behavior of a face-directed octahedral metal-organic supercontainer featuring one endo cavity and six exo cavities was thoroughly examined in chloroform solution through ultraviolet-visible (UV-Vis) titration technique using two representative drug molecules as the guests. The titration curves and their nonlinear fit to Hill equation strongly suggest the efficient encapsulation of the guest molecules by the synthetic host, which exhibit interesting cooperative and stepwise binding behavior. Based on the control experiments using tetranuclear complex as a reference, it is clear that two equivalents of the guest molecules are initially encapsulated inside the endo cavity, followed by the trapping of six additional equivalents of the drug molecules through six exo cavities (1 eq. per exo cavity), and the remaining guests are entrapped by the external pockets. The results provide an in-depth understanding of the cooperative binding behavior of metal-organic supercontainers, which opens up new opportunities for designing synthetic receptors for truly biomimetic functional applications.


Subject(s)
Calixarenes/chemistry , Metal-Organic Frameworks/chemistry , Metals/chemistry , Pantoprazole/metabolism , Rabeprazole/metabolism , Sulfinic Acids/chemistry , Binding Sites , Calixarenes/metabolism , Metal-Organic Frameworks/metabolism , Models, Molecular , Molecular Structure , Sulfinic Acids/metabolism
7.
J Theor Biol ; 482: 109983, 2019 12 07.
Article in English | MEDLINE | ID: mdl-31445016

ABSTRACT

The origin of large genomes that underlies the long standing "C-value enigma" is only partially explained by selfish DNA. We investigated insertions and deletions (indels) of nucleotides and discussed their relevance in size evolution of random biological sequences (RBS) and genomes. By developing a probabilistic model of RBS based on size evolution of expandable sites in a thought perfect genome, it was found that insertion bias engenders exponential increase of average RBS sizes. When combined with existing large segments of genome that are not subject to selection pressure (e.g. selfish DNA), such insertion bias results in explosive expansion of genomes, and therefore helps explain the "C value enigma" besides selfish DNA. Such increase of RBS size is caused by the fundamental asymmetry of indels, with insertions result in more available sites and deletions result in less deletable nucleotides. In qualitative agreement with the size distribution of known genomes, tails of RBS size distributions exhibit exponential decay with probabilities of larger RBS segments being smaller. Unsurprisingly, a slight deletion bias (higher deletions probabilities) results in a slow decrease of average RBS size and may lead to their eventual vanishing. Contrary to intuition, strictly balanced insertion and deletion results in linearly increasing instead of completely fixed RBS size. Nonetheless, such slow linear increase of average RBS sizes with time are small in magnitude and are consequently not influential on genome size evolution, and certainly not a major contributor for the "C-value enigma". Our model suggested that insertion bias of nucleotides may provide complementary explanation for large genomes besides selfish DNA. The fundamental indel asymmetry is applicable for all forms of genomic insertions and deletions. Long-lasting exponential increase of genome size present energy and material requirement that is impossible to sustain. We therefore concluded that if there were explosively accelerating expansion caused by significant effective insertion bias for any survival species, it must have occurred sporadically. Our model also provided an explanation for the observed proportional evolution of genome size.


Subject(s)
Evolution, Molecular , Genome Size/genetics , INDEL Mutation/physiology , Sequence Alignment , Animals , Base Sequence , Humans , Models, Theoretical , Mutagenesis, Insertional/physiology , Random Allocation , Sequence Alignment/methods , Sequence Deletion/physiology
8.
BMC Nephrol ; 20(1): 409, 2019 11 13.
Article in English | MEDLINE | ID: mdl-31722677

ABSTRACT

BACKGROUND: Delayed graft function (DGF) is an important complication of kidney transplantation and can be diagnosed according to different definitions. DGF has been suggested to be associated with the long-term outcome of kidney transplantation surgery. However, the best DGF definition for predicting renal transplant outcomes in Chinese donations after cardiac death (DCDs) remains to be determined. METHOD: A total of 372 DCD kidney transplant recipients from June 2013 to July 2017 in the First Affiliated Hospital of Xi'an Jiaotong University were included in this retrospective study to compare 6 different DGF definitions. The relationships of the DGF definitions with transplant outcome were analyzed, including graft loss (GL) and death-censored graft loss (death-censored GL). Renal function indicators, including one-year estimated glomerular filtration rate (eGFR) and three-year eGFR, and were compared between different DGF groups. RESULTS: The incidence of DGF varied from 4.19 to 35.22% according to the different DGF diagnoses. All DGF definitions were significantly associated with three-year GL as well as death-censored GL. DGF based on requirement of hemodialysis within the first week had the best predictive value for GL (AUC 0.77), and DGF based on sCr variation during the first 3 days post-transplant had the best predictive value for three-year death-censored GL (AUC 0.79). Combination of the 48-h sCr reduction ratio and classical DGF can improve the AUC for GL (AUC 0.85) as well as the predictive accuracy for death-censored GL (83.3%). CONCLUSION: DGF was an independent risk factor for poor transplant outcome. The combination of need for hemodialysis within the first week and the 48-h serum creatinine reduction rate has a better predictive value for patient and poor graft outcome.


Subject(s)
Delayed Graft Function/diagnosis , Kidney Transplantation/adverse effects , Postoperative Complications/diagnosis , Tissue Donors , Adult , Area Under Curve , China , Creatinine/blood , Delayed Graft Function/epidemiology , Female , Glomerular Filtration Rate , Graft Survival , Heart Arrest , Humans , Immunosuppression Therapy/methods , Immunosuppressive Agents/therapeutic use , Incidence , Kaplan-Meier Estimate , Kidney/physiology , Kidney Transplantation/mortality , Male , Middle Aged , Postoperative Complications/epidemiology , Retrospective Studies , Risk Factors , Sensitivity and Specificity , Time Factors , Treatment Outcome
9.
J Cardiovasc Pharmacol ; 72(4): 176-185, 2018 10.
Article in English | MEDLINE | ID: mdl-29985281

ABSTRACT

Simvastatin treatment is cardioprotective in patients undergoing noncoronary artery cardiac surgery. However, the mechanisms by which simvastatin treatment protects the myocardium under these conditions are not fully understood. Seventy patients undergoing noncoronary cardiac surgery, 35 from a simvastatin treatment group and 35 from a control treatment group, were enrolled in our clinical study. Simvastatin (20 mg/d) was administered preoperatively for 5-7 days. Myocardial tissue biopsies were taken before and after surgery. Apoptosis was detected by TUNEL staining. The expressions of Bcl-2 and Bak in myocardial tissue were detected by immunoblotting. The expressions of miRNA and Bcl-2 mRNA were detected by quantitative real-time polymerase chain reaction assays. Cardiomyocytes were isolated from rat and cultured cells. MiR-15a-5p mimic was transfected into cardiomyocytes, and the Bcl-2 was detected by immunoblotting. TUNEL staining showed significantly less myocardial apoptosis in the simvastatin treatment group when compared with the control treatment group. Protein expression of Bcl-2 was increased in the simvastatin treatment group before surgery, and Bak expression was increased in the control treatment group after surgery. Further comparisons showed that Bcl-2/Bak ratios were reduced in the control treatment group but were not significantly changed in the simvastatin treatment group after surgery. Furthermore, microarray assays revealed that miR-15a-5p was significantly decreased by simvastatin treatment. This was validated by quantitative real-time polymerase chain reaction analysis. MiR-15a-5p was predicted to target Bcl-2 mRNA at nucleotide positions 2529-2536. This was validated by luciferase binding assays. Coincident with the change in miR-15a-5p, the mRNA expression of Bcl-2 was increased in the simvastatin treatment group. MiR-15a-5p mimic significantly inhibited Bcl-2 expression in cardiomyocytes. Our findings strongly suggest that simvastatin treatment preoperatively protected the myocardium in patients undergoing noncoronary artery cardiac surgery, at least in part, by inhibiting apoptosis via suppressing miR-15a-5p expression, leading to increasing expression of Bcl-2 and decreasing expression of Bak.


Subject(s)
Apoptosis/drug effects , Elective Surgical Procedures/adverse effects , Heart Diseases/prevention & control , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , MicroRNAs/metabolism , Myocytes, Cardiac/drug effects , Simvastatin/administration & dosage , Adult , Animals , Cells, Cultured , China , Drug Administration Schedule , Female , Heart Diseases/genetics , Heart Diseases/metabolism , Heart Diseases/pathology , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Male , MicroRNAs/genetics , Middle Aged , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/pathology , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , Rats, Sprague-Dawley , Signal Transduction/drug effects , Simvastatin/adverse effects , Treatment Outcome , bcl-2 Homologous Antagonist-Killer Protein/genetics , bcl-2 Homologous Antagonist-Killer Protein/metabolism
10.
J Transl Med ; 15(1): 4, 2017 01 04.
Article in English | MEDLINE | ID: mdl-28049487

ABSTRACT

BACKGROUND: We previously demonstrated that endothelial microparticles (EMPs) are increased in mitral valve diseases and impair valvular endothelial cell function. Perioperative systemic inflammation is an important risk factor and complication of cardiac surgery. In this study, we investigate whether EMPs increase in congenital heart diseases to promote inflammation and endothelial dysfunction. METHODS: The level of plasma EMPs in 20 patients with atrial septal defect (ASD), 23 patients with ventricular septal defect (VSD), and 30 healthy subjects were analyzed by flow cytometry. EMPs generated from human umbilical vascular endothelial cells (HUVECs) were injected into C57BL6 mice, or cultured with HUVECs without or with siRNAs targeting P38 MAPK. The expression and/or phosphorylation of endothelial nitric oxide synthase (eNOS), P38 MAPK, and caveolin-1 in mouse heart and/or in cultured HUVECs were determined. We evaluated generation of nitric oxide (NO) in mouse hearts, and levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in cultured HUVECs and in mice. RESULTS: EMPs were significantly elevated in patients with ASD and VSD, especially in those with pulmonary hypertension when compared with controls. EMPs increased caveolin-1 expression and P38 MAPK phosphorylation and decreased eNOS phosphorylation and NO production in mouse hearts. EMPs stimulated P38 MAPK expression, TNF-α and IL-6 production, which were all inhibited by siRNAs targeting P38 MAPK in cultured HUVECs. CONCLUSIONS: EMPs were increased in adult patients with congenital heart diseases and may contribute to increased inflammation leading to endothelial dysfunction via P38 MAPK-dependent pathways. This novel data provides a potential therapeutic target to address important complications of surgery of congenial heart disease.


Subject(s)
Cell-Derived Microparticles/metabolism , Endothelial Cells/metabolism , Heart Defects, Congenital/pathology , Heart Defects, Congenital/physiopathology , Adult , Animals , Caveolin 1/metabolism , Demography , Echocardiography, Doppler , Endothelium, Vascular/diagnostic imaging , Endothelium, Vascular/pathology , Endothelium, Vascular/physiopathology , Female , Heart Defects, Congenital/blood , Heart Defects, Congenital/diagnostic imaging , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Interleukin-6/blood , Male , Mice , Nitric Oxide/metabolism , Nitric Oxide Synthase Type III/metabolism , Phosphorylation , Tumor Necrosis Factor-alpha/blood , p38 Mitogen-Activated Protein Kinases/metabolism
11.
Molecules ; 22(3)2017 Feb 28.
Article in English | MEDLINE | ID: mdl-28264511

ABSTRACT

ß-galactosidase was successfully encapsulated within an amino-functionalised silica matrix using a "fish-in-net" approach and molecular imprinting technique followed by covalent binding of lysozyme via a glutaraldehyde-based method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy were used to characterise the silica matrix hosting the two enzymes. Both encapsulated ß-galactosidase and bound lysozyme exhibited high enzymatic activities and outstanding operational stability in model reactions. Moreover, enzyme activities of the co-immobilised enzymes did not obviously change relative to enzymes immobilised separately. In antibacterial tests, bound lysozyme exhibited 95.5% and 89.6% growth inhibition of Staphylococcus aureus ATCC (American type culture collection) 653 and Escherichia coli ATCC 1122, respectively. In milk treated with co-immobilised enzymes, favourable results were obtained regarding reduction of cell viability and high lactose hydrolysis rate. In addition, when both co-immobilised enzymes were employed to treat milk, high operational and storage stabilities were observed. The results demonstrate that the use of co-immobilised enzymes holds promise as an industrial strategy for producing low lactose milk to benefit people with lactose intolerance.


Subject(s)
Anti-Infective Agents/chemistry , Lactose/chemistry , Muramidase/chemistry , Silicon Dioxide/chemistry , beta-Galactosidase/chemistry , Animals , Anti-Infective Agents/pharmacology , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Escherichia coli/drug effects , Hydrolysis/drug effects , Microscopy, Electron, Scanning , Milk/chemistry , Molecular Imprinting , Muramidase/pharmacology , Spectroscopy, Fourier Transform Infrared , Staphylococcus aureus/drug effects , X-Ray Diffraction , beta-Galactosidase/pharmacology
12.
Am J Physiol Endocrinol Metab ; 311(4): E781-E790, 2016 10 01.
Article in English | MEDLINE | ID: mdl-27600825

ABSTRACT

Endothelial dysfunction is a key early step in atherosclerosis. 25-Hydroxycholesterol (25-OHC) is found in atherosclerotic lesions. However, whether 25-OHC promotes atherosclerosis is unclear. Here, we hypothesized that 25-OHC, a proinflammatory lipid, can impair endothelial function, which may play an important role in atherosclerosis. Bovine aortic endothelial cells were incubated with 25-OHC. Endothelial cell proliferation, migration, and tube formation were measured. Nitric oxide (NO) production and superoxide anion generation were determined. The expression and phosphorylation of endothelial NO synthase (eNOS) and Akt as well as the association of eNOS and heat shock protein (HSP)90 were detected by immunoblot analysis and immunoprecipitation. Endothelial cell apoptosis was monitored by TUNEL staining and caspase-3 activity, and expression of Bcl-2, Bax, cleaved caspase-9, and cleaved caspase-3 were detected by immunoblot analysis. Finally, aortic rings from Sprague-Dawley rats were isolated and treated with 25-OHC, and endothelium-dependent vasodilation was evaluated. 25-OHC significantly inhibited endothelial cell proliferation, migration, and tube formation. 25-OHC markedly decreased NO production and increased superoxide anion generation. 25-OHC reduced the phosphorylation of Akt and eNOS and the association of eNOS and HSP90. 25-OHC also enhanced endothelial cell apoptosis by decreasing Bcl-2 expression and increasing cleaved caspase-9 and cleaved caspase-3 expressions as well as caspase-3 activity. 25-OHC impaired endothelium-dependent vasodilation. These data demonstrated that 25-OHC could impair endothelial function by uncoupling and inhibiting eNOS activity as well as by inducing endothelial cell apoptosis. Our findings indicate that 25-OHC may play an important role in regulating atherosclerosis.


Subject(s)
Endothelium/drug effects , Enzyme Inhibitors/pharmacology , Hydroxycholesterols/pharmacology , Nitric Oxide Synthase Type III/antagonists & inhibitors , Uncoupling Agents/pharmacology , Vasodilation/drug effects , Animals , Apoptosis/drug effects , Cattle , Cell Movement/drug effects , Cell Proliferation/drug effects , Endothelial Cells/drug effects , Endothelial Cells/metabolism , In Vitro Techniques , Inflammation Mediators/metabolism , Nitric Oxide/biosynthesis , Rats , Rats, Sprague-Dawley , Superoxides/metabolism
13.
Proc Natl Acad Sci U S A ; 108(31): E383-91, 2011 Aug 02.
Article in English | MEDLINE | ID: mdl-21646511

ABSTRACT

Autotransporters are bacterial virulence factors that consist of an N-terminal extracellular ("passenger") domain and a C-terminal ß barrel domain ("ß domain") that resides in the outer membrane. Here we used an in vivo site-specific photocrosslinking approach to gain insight into the mechanism by which the ß domain is integrated into the outer membrane and the relationship between ß domain assembly and passenger domain secretion. We found that periplasmic chaperones and specific components of the ß barrel assembly machinery (Bam) complex interact with the ß domain of the Escherichia coli O157:H7 autotransporter extracellular serine protease P (EspP) in a temporally and spatially regulated fashion. Although the chaperone Skp initially interacted with the entire ß domain, BamA, BamB, and BamD subsequently interacted with discrete ß domain regions. BamB and BamD remained bound to the ß domain longer than BamA and therefore appeared to function at a later stage of assembly. Interestingly, we obtained evidence that the completion of ß domain assembly is regulated by an intrinsic checkpoint mechanism that requires the completion of passenger domain secretion. In addition to leading to a detailed model of autotransporter biogenesis, our results suggest that the lipoprotein components of the Bam complex play a direct role in the membrane integration of ß barrel proteins.


Subject(s)
Escherichia coli O157/metabolism , Escherichia coli Proteins/metabolism , Periplasm/metabolism , Serine Endopeptidases/metabolism , Bacterial Outer Membrane Proteins/genetics , Bacterial Outer Membrane Proteins/metabolism , Binding Sites/genetics , Blotting, Western , Carrier Proteins/genetics , Carrier Proteins/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Escherichia coli O157/genetics , Escherichia coli Proteins/chemistry , Escherichia coli Proteins/genetics , Immunoprecipitation , Lipoproteins/metabolism , Models, Biological , Models, Molecular , Molecular Chaperones/genetics , Molecular Chaperones/metabolism , Multiprotein Complexes/metabolism , Mutation , Peptidylprolyl Isomerase/genetics , Peptidylprolyl Isomerase/metabolism , Protein Binding/radiation effects , Protein Structure, Tertiary , Serine Endopeptidases/chemistry , Serine Endopeptidases/genetics , Time Factors , Ultraviolet Rays
14.
Front Public Health ; 12: 1320918, 2024.
Article in English | MEDLINE | ID: mdl-38414903

ABSTRACT

Background and aims: Obesity and insulin resistance are well-known important risk factors for hypertension. This study aimed to investigate the mediating effect of the triglyceride-glucose index (TyG) in the association between Chinese visceral obesity index (CVAI) and hypertension among Chinese middle-aged and older adults. Methods: A total of 10,322 participants aged 45 years and older from CHARLS (2011-2018) were included. Baseline data were collected in 2011 and hypertension incidence data were gathered during follow-up in 2013, 2015 and 2018. Multivariate logistic regression models were constructed to investigate the association of CVAI and TyG with the incidence of hypertension. Additionally, mediation analyses were conducted to evaluate the mediating role of the TyG index in the relationship between CVAI and hypertension. Subgroup analysis was also performed. Results: A total of 2,802 participants developed hypertension during the follow-up period. CVAI and TyG index were independently and significantly associated with hypertension incidence. Increasing quartiles of CVAI and TyG index were associated with high hypertension incidence in middle-aged and older adults. The TyG index was identified as a mediator in the relationship between CVAI and hypertension incidence, with a mediation effect (95% confidence interval) was 12.38% (6.75, 31.81%). Conclusion: Our study found that CVAI and TyG were independently associated with hypertension incidence. TyG played a partial mediating effect in the positive association between CVAI and hypertension incidence.


Subject(s)
Hypertension , Insulin Resistance , Middle Aged , Humans , Aged , Incidence , Longitudinal Studies , Retirement , Obesity/epidemiology , China/epidemiology , Glucose , Hypertension/epidemiology , Triglycerides
15.
Proc Natl Acad Sci U S A ; 107(41): 17739-44, 2010 Oct 12.
Article in English | MEDLINE | ID: mdl-20876094

ABSTRACT

Autotransporters are bacterial virulence factors consisting of an N-terminal "passenger domain" that is secreted in a C- to-N-terminal direction and a C-terminal "ß domain" that resides in the outer membrane (OM). Although passenger domain secretion does not appear to use ATP, the energy source for this reaction is unknown. Here, we show that efficient secretion of the passenger domain of the Escherichia coli O157:H7 autotransporter EspP requires the stable folding of a C-terminal ≈17-kDa passenger domain segment. We found that mutations that perturb the folding of this segment do not affect its translocation across the OM but impair the secretion of the remainder of the passenger domain. Interestingly, an examination of kinetic folding mutants strongly suggested that the ≈17-kDa segment folds in the extracellular space. By mutagenizing the ≈17-kDa segment, we also fortuitously isolated a unique translocation intermediate. Analysis of this intermediate suggests that a heterooligomer that facilitates the membrane integration of OM proteins (the Bam complex) also promotes the surface exposure of the ≈17-kDa segment. Our results provide direct evidence that protein folding can drive translocation and help to clarify the mechanism of autotransporter secretion.


Subject(s)
Bacterial Outer Membrane Proteins/metabolism , Escherichia coli O157/metabolism , Escherichia coli Proteins/metabolism , Protein Folding , Protein Structure, Tertiary/genetics , Serine Endopeptidases/metabolism , Virulence Factors/metabolism , Kinetics , Mutation/genetics
16.
Math Biosci Eng ; 20(12): 21147-21162, 2023 Nov 27.
Article in English | MEDLINE | ID: mdl-38124591

ABSTRACT

Factorization reduces computational complexity, and is therefore an important tool in statistical machine learning of high dimensional systems. Conventional molecular modeling, including molecular dynamics and Monte Carlo simulations of molecular systems, is a large research field based on approximate factorization of molecular interactions. Recently, the local distribution theory was proposed to factorize joint distribution of a given molecular system into trainable local distributions. Belief propagation algorithms are a family of exact factorization algorithms for (junction) trees, and are extended to approximate loopy belief propagation algorithms for graphs with loops. Despite the fact that factorization of probability distribution is the common foundation, computational research in molecular systems and machine learning studies utilizing belief propagation algorithms have been carried out independently with respective track of algorithm development. The connection and differences among these factorization algorithms are briefly presented in this perspective, with the hope to intrigue further development of factorization algorithms for physical modeling of complex molecular systems.

17.
ACS Appl Mater Interfaces ; 15(24): 29252-29258, 2023 Jun 21.
Article in English | MEDLINE | ID: mdl-37294737

ABSTRACT

Coordination cages with a well-defined nanocavity are a class of promising supramolecular materials for molecular recognition and sensing. However, their applications in sequential sensing of multiple types of pollutants are highly desirable yet extremely limiting and challenging. Herein, we demonstrate a convenient strategy to develop a supramolecular fluorescence sensor for sequentially detecting environmental pollutants of aluminum ions and nitrofurantoin. A coordination cage (Ni-NTB), adopting an octahedral structure with triphenylamine chromophores occupying on the faces, is weakly emissive in solution due to the intramolecular rotations of the phenyl rings. Ni-NTB exhibits sensitive and selective fluorescence "off-on-off" processes during consecutive sensing of Al3+ and nitrofurantoin, an antibacterial drug. These sequential detection processes are highly interference-tolerant and visually observable with the naked eye. Mechanism studies reveal that the fluorescence switch is controllable by tuning the degree of intramolecular rotations of the phenyl rings and the pathway of intermolecular charge transfer, which is associated with the host-guest interaction. Moreover, the fabrication of Ni-NTB on test strips enabled a quick naked-eye sequential sensing of Al3+ and nitrofurantoin in seconds. Hence, this novel supramolecular fluorescence "off-on-off" sensing platform provides a new approach to developing supramolecular functional materials for monitoring environmental pollution.

18.
Cell Discov ; 9(1): 20, 2023 Feb 21.
Article in English | MEDLINE | ID: mdl-36810288

ABSTRACT

Immune checkpoint blockade (ICB) therapy targeting PD-1/PD-L1 has shown durable clinical benefits in lung cancer. However, many patients respond poorly to ICB treatment, underscoring an incomplete understanding of PD-L1 regulation and therapy resistance. Here, we find that MTSS1 is downregulated in lung adenocarcinoma, leading to PD-L1 upregulation, impairment of CD8+ lymphocyte function, and enhanced tumor progression. MTSS1 downregulation correlates with improved ICB efficacy in patients. Mechanistically, MTSS1 interacts with the E3 ligase AIP4 for PD-L1 monoubiquitination at Lysine 263, leading to PD-L1 endocytic sorting and lysosomal degradation. In addition, EGFR-KRAS signaling in lung adenocarcinoma suppresses MTSS1 and upregulates PD-L1. More importantly, combining AIP4-targeting via the clinical antidepressant drug clomipramine and ICB treatment improves therapy response and effectively suppresses the growth of ICB-resistant tumors in immunocompetent mice and humanized mice. Overall, our study discovers an MTSS1-AIP4 axis for PD-L1 monoubiquitination and reveals a potential combinatory therapy with antidepressants and ICB.

19.
Cell Res ; 33(6): 464-478, 2023 06.
Article in English | MEDLINE | ID: mdl-37142671

ABSTRACT

Estrogen receptor (ER)-positive luminal breast cancer is a subtype with generally lower risk of metastasis to most distant organs. However, bone recurrence occurs preferentially in luminal breast cancer. The mechanisms of this subtype-specific organotropism remain elusive. Here we show that an ER-regulated secretory protein SCUBE2 contributes to bone tropism of luminal breast cancer. Single-cell RNA sequencing analysis reveals osteoblastic enrichment by SCUBE2 in early bone-metastatic niches. SCUBE2 facilitates release of tumor membrane-anchored SHH to activate Hedgehog signaling in mesenchymal stem cells, thus promoting osteoblast differentiation. Osteoblasts deposit collagens to suppress NK cells via the inhibitory LAIR1 signaling and promote tumor colonization. SCUBE2 expression and secretion are associated with osteoblast differentiation and bone metastasis in human tumors. Targeting Hedgehog signaling with Sonidegib and targeting SCUBE2 with a neutralizing antibody both effectively suppress bone metastasis in multiple metastasis models. Overall, our findings provide a mechanistic explanation for bone preference in luminal breast cancer metastasis and new approaches for metastasis treatment.


Subject(s)
Breast Neoplasms , Humans , Female , Hedgehog Proteins/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Calcium-Binding Proteins , Signal Transduction , Cell Line, Tumor
20.
Zhongguo Zhong Yao Za Zhi ; 37(19): 2910-2, 2012 Oct.
Article in Zh | MEDLINE | ID: mdl-23270232

ABSTRACT

OBJECTIVE: To study the inhibitory activity of Aeschynanthus maculatus on alpha-glucosidase. METHOD: The inhibilitory model of in vitro alpha-glucosidase was established. Active extracts of A. maculatus were isolated and identified bymultiple chromatographic methods, and their molecular structures were identifiied by spectral techniques. RESULT: Seven coumpounts were isolated from A. maculatus and isolated as lupeol(1), stigmasterol(2), ursolic acid(3), stigmast-5,22(E)-diene-3beta-ol(4), beta-daucosterol(5), 3-hydroxy-12-taraxasten-28-oic-acid(6) and oleanic acid(7). Compounds 1 (IC50 25.41 mg x L(-1)),3(IC0 4.42 mg L(-1)),4(IC50 11.50 mg x L(-1)),6(IC50 14.17 mg x L(-1)) and 7(IC50 2.88 mg x L(-1)) had higher inhibitory activities than that of acarbose (IC50 1103.01 mg x L(-1)) as the positive control drug. CONCLUSION: Compound 1-7 were isolated from this plant for the first time. Compound 6 was isolated from Gesneriaceae family for the first time. Compound 7 was isolated from Aeschynanthus genus for the first time.


Subject(s)
Enzyme Inhibitors/pharmacology , Ferns/chemistry , Glycoside Hydrolase Inhibitors , Plant Exudates/pharmacology , Enzyme Inhibitors/chemistry , Plant Exudates/chemistry
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