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1.
Nat Commun ; 15(1): 2460, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38503747

RESUMO

The mammalian orthoreovirus (reovirus) σNS protein is required for formation of replication compartments that support viral genome replication and capsid assembly. Despite its functional importance, a mechanistic understanding of σNS is lacking. We conducted structural and biochemical analyses of a σNS mutant that forms dimers instead of the higher-order oligomers formed by wildtype (WT) σNS. The crystal structure shows that dimers interact with each other using N-terminal arms to form a helical assembly resembling WT σNS filaments in complex with RNA observed using cryo-EM. The interior of the helical assembly is of appropriate diameter to bind RNA. The helical assembly is disrupted by bile acids, which bind to the same site as the N-terminal arm. This finding suggests that the N-terminal arm functions in conferring context-dependent oligomeric states of σNS, which is supported by the structure of σNS lacking an N-terminal arm. We further observed that σNS has RNA chaperone activity likely essential for presenting mRNA to the viral polymerase for genome replication. This activity is reduced by bile acids and abolished by N-terminal arm deletion, suggesting that the activity requires formation of σNS oligomers. Our studies provide structural and mechanistic insights into the function of σNS in reovirus replication.


Assuntos
Orthoreovirus , Reoviridae , Animais , Orthoreovirus/genética , Replicação Viral , Reoviridae/genética , RNA/metabolismo , Ácidos e Sais Biliares , RNA Viral/genética , Mamíferos/genética
2.
Proc Natl Acad Sci U S A ; 121(12): e2313513121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38483989

RESUMO

Cooperative interactions between amino acids are critical for protein function. A genetic reflection of cooperativity is epistasis, which is when a change in the amino acid at one position changes the sequence requirements at another position. To assess epistasis within an enzyme active site, we utilized CTX-M ß-lactamase as a model system. CTX-M hydrolyzes ß-lactam antibiotics to provide antibiotic resistance, allowing a simple functional selection for rapid sorting of modified enzymes. We created all pairwise mutations across 17 active site positions in the ß-lactamase enzyme and quantitated the function of variants against two ß-lactam antibiotics using next-generation sequencing. Context-dependent sequence requirements were determined by comparing the antibiotic resistance function of double mutations across the CTX-M active site to their predicted function based on the constituent single mutations, revealing both positive epistasis (synergistic interactions) and negative epistasis (antagonistic interactions) between amino acid substitutions. The resulting trends demonstrate that positive epistasis is present throughout the active site, that epistasis between residues is mediated through substrate interactions, and that residues more tolerant to substitutions serve as generic compensators which are responsible for many cases of positive epistasis. Additionally, we show that a key catalytic residue (Glu166) is amenable to compensatory mutations, and we characterize one such double mutant (E166Y/N170G) that acts by an altered catalytic mechanism. These findings shed light on the unique biochemical factors that drive epistasis within an enzyme active site and will inform enzyme engineering efforts by bridging the gap between amino acid sequence and catalytic function.


Assuntos
Escherichia coli , beta-Lactamases , Escherichia coli/genética , Domínio Catalítico/genética , Mutação , Substituição de Aminoácidos , beta-Lactamases/química
3.
Front Oncol ; 14: 1292319, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38327739

RESUMO

Background: Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver malignancy with a steadily increasing incidence worldwide. ICC has insidious onset, rapid progression, and poor prognosis. More multidisciplinary clinical studies are needed to continuously explore safer and more efficient diagnosis and treatment modes for ICC. Methods and results: A 66-year-old female patient with ICC rapidly developed systemic multiple metastases after surgery, and the first-line two-drug combination chemotherapy was not effective. Due to cyclin-dependent kinase inhibitor 2A mutation and programmed cell death-ligand 1-positive, a partial response and progression-free survival of 9.5 months were achieved after a second-line treatment with cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) combined with immunotherapy. The patient developed thromboembolism 7 months after treatment and died due to disseminated intravascular coagulation. Conclusion: The combination of targeted and immune therapy has revealed a potentially effective regimen for the effective treatment of patients with ICC, which needs to be observed in larger clinical studies. The thromboembolism rates in real-world patients treated with CDK4/6 inhibitors are higher than those reported in clinical trials, and the application of prophylactic anticoagulation in this patient population may be questionable.

4.
J Biol Chem ; 300(1): 105493, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38000656

RESUMO

Klebsiella pneumoniae carbapenemase 2 (KPC-2) is an important source of drug resistance as it can hydrolyze and inactivate virtually all ß-lactam antibiotics. KPC-2 is potently inhibited by avibactam via formation of a reversible carbamyl linkage of the inhibitor with the catalytic serine of the enzyme. However, the use of avibactam in combination with ceftazidime (CAZ-AVI) has led to the emergence of CAZ-AVI-resistant variants of KPC-2 in clinical settings. One such variant, KPC-44, bears a 15 amino acid duplication in one of the active-site loops (270-loop). Here, we show that the KPC-44 variant exhibits higher catalytic efficiency in hydrolyzing ceftazidime, lower efficiency toward imipenem and meropenem, and a similar efficiency in hydrolyzing ampicillin, than the WT KPC-2 enzyme. In addition, the KPC-44 variant enzyme exhibits 12-fold lower AVI carbamylation efficiency than the KPC-2 enzyme. An X-ray crystal structure of KPC-44 showed that the 15 amino acid duplication results in an extended and partially disordered 270-loop and also changes the conformation of the adjacent 240-loop, which in turn has altered interactions with the active-site omega loop. Furthermore, a structure of KPC-44 with avibactam revealed that formation of the covalent complex results in further disorder in the 270-loop, suggesting that rearrangement of the 270-loop of KPC-44 facilitates AVI carbamylation. These results suggest that the duplication of 15 amino acids in the KPC-44 enzyme leads to resistance to CAZ-AVI by modulating the stability and conformation of the 270-, 240-, and omega-loops.


Assuntos
Ceftazidima , Farmacorresistência Bacteriana , Modelos Moleculares , Humanos , Aminoácidos/genética , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , beta-Lactamases/química , beta-Lactamases/genética , beta-Lactamases/metabolismo , Ceftazidima/farmacologia , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Farmacorresistência Bacteriana/genética , Cristalografia por Raios X , Domínio Catalítico/genética , Estrutura Terciária de Proteína
5.
Protein Cell ; 15(1): 52-68, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-37294900

RESUMO

Here, we report a previously unrecognized syndromic neurodevelopmental disorder associated with biallelic loss-of-function variants in the RBM42 gene. The patient is a 2-year-old female with severe central nervous system (CNS) abnormalities, hypotonia, hearing loss, congenital heart defects, and dysmorphic facial features. Familial whole-exome sequencing (WES) reveals that the patient has two compound heterozygous variants, c.304C>T (p.R102*) and c.1312G>A (p.A438T), in the RBM42 gene which encodes an integral component of splicing complex in the RNA-binding motif protein family. The p.A438T variant is in the RRM domain which impairs RBM42 protein stability in vivo. Additionally, p.A438T disrupts the interaction of RBM42 with hnRNP K, which is the causative gene for Au-Kline syndrome with overlapping disease characteristics seen in the index patient. The human R102* or A438T mutant protein failed to fully rescue the growth defects of RBM42 ortholog knockout ΔFgRbp1 in Fusarium while it was rescued by the wild-type (WT) human RBM42. A mouse model carrying Rbm42 compound heterozygous variants, c.280C>T (p.Q94*) and c.1306_1308delinsACA (p.A436T), demonstrated gross fetal developmental defects and most of the double mutant animals died by E13.5. RNA-seq data confirmed that Rbm42 was involved in neurological and myocardial functions with an essential role in alternative splicing (AS). Overall, we present clinical, genetic, and functional data to demonstrate that defects in RBM42 constitute the underlying etiology of a new neurodevelopmental disease which links the dysregulation of global AS to abnormal embryonic development.


Assuntos
Fissura Palatina , Cardiopatias Congênitas , Deficiência Intelectual , Feminino , Animais , Camundongos , Humanos , Pré-Escolar , Deficiência Intelectual/genética , Cardiopatias Congênitas/genética , Facies , Hipotonia Muscular
6.
J Med Chem ; 67(1): 620-642, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38117688

RESUMO

ß-Lactamase enzymes hydrolyze and thereby provide bacterial resistance to the important ß-lactam class of antibiotics. The OXA-48 and NDM-1 ß-lactamases cause resistance to the last-resort ß-lactams, carbapenems, leading to a serious public health threat. Here, we utilized DNA-encoded chemical library (DECL) technology to discover novel ß-lactamase inhibitors. We exploited the ß-lactamase enzyme-substrate binding interactions and created a DECL targeting the carboxylate-binding pocket present in all ß-lactamases. A library of 106 compounds, each containing a carboxylic acid or a tetrazole as an enzyme recognition element, was designed, constructed, and used to identify OXA-48 and NDM-1 inhibitors with micromolar to nanomolar potency. Further optimization led to NDM-1 inhibitors with increased potencies and biological activities. This work demonstrates that the carboxylate-binding pocket-targeting DECL, designed based on substrate binding information, aids in inhibitor identification and led to the discovery of novel non-ß-lactam pharmacophores for the development of ß-lactamase inhibitors for enzymes of different structural and mechanistic classes.


Assuntos
Antibacterianos , Inibidores de beta-Lactamases , Inibidores de beta-Lactamases/farmacologia , Inibidores de beta-Lactamases/química , Antibacterianos/farmacologia , Antibacterianos/química , beta-Lactamases/metabolismo , beta-Lactamas/farmacologia , Penicilinas , DNA , Testes de Sensibilidade Microbiana
7.
Nat Commun ; 14(1): 6516, 2023 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-37845211

RESUMO

Acute gastroenteritis caused by human noroviruses (HuNoVs) is a significant global health and economic burden and is without licensed vaccines or antiviral drugs. The GII.4 HuNoV causes most epidemics worldwide. This virus undergoes epochal evolution with periodic emergence of variants with new antigenic profiles and altered specificity for histo-blood group antigens (HBGA), the determinants of cell attachment and susceptibility, hampering the development of immunotherapeutics. Here, we show that a llama-derived nanobody M4 neutralizes multiple GII.4 variants with high potency in human intestinal enteroids. The crystal structure of M4 complexed with the protruding domain of the GII.4 capsid protein VP1 revealed a conserved epitope, away from the HBGA binding site, fully accessible only when VP1 transitions to a "raised" conformation in the capsid. Together with dynamic light scattering and electron microscopy of the GII.4 VLPs, our studies suggest a mechanism in which M4 accesses the epitope by altering the conformational dynamics of the capsid and triggering its disassembly to neutralize GII.4 infection.


Assuntos
Antígenos de Grupos Sanguíneos , Infecções por Caliciviridae , Norovirus , Humanos , Proteínas do Capsídeo/química , Capsídeo/metabolismo , Norovirus/genética , Sítios de Ligação , Epitopos/metabolismo , Antígenos de Grupos Sanguíneos/metabolismo
9.
bioRxiv ; 2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37577609

RESUMO

The reovirus σNS RNA-binding protein is required for formation of intracellular compartments during viral infection that support viral genome replication and capsid assembly. Despite its functional importance, a mechanistic understanding of σNS is lacking. We conducted structural and biochemical analyses of an R6A mutant of σNS that forms dimers instead of the higher-order oligomers formed by wildtype (WT) σNS. The crystal structure of selenomethionine-substituted σNS-R6A reveals that the mutant protein forms a stable antiparallel dimer, with each subunit having a well-folded central core and a projecting N-terminal arm. The dimers interact with each other by inserting the N-terminal arms into a hydrophobic pocket of the neighboring dimers on either side to form a helical assembly that resembles filaments of WT σNS in complex with RNA observed using cryo-EM. The interior of the crystallographic helical assembly is positively charged and of appropriate diameter to bind RNA. The helical assembly is disrupted by bile acids, which bind to the same hydrophobic pocket as the N-terminal arm, as demonstrated in the crystal structure of σNS-R6A in complex with bile acid, suggesting that the N-terminal arm functions in conferring context-dependent oligomeric states of σNS. This idea is supported by the structure of σNS lacking the N-terminal arm. We discovered that σNS displays RNA helix destabilizing and annealing activities, likely essential for presenting mRNA to the viral RNA-dependent RNA polymerase for genome replication. The RNA chaperone activity is reduced by bile acids and abolished by N-terminal arm deletion, suggesting that the activity requires formation of σNS oligomers. Our studies provide structural and mechanistic insights into the function of σNS in reovirus replication.

10.
Am J Cancer Res ; 13(5): 1766-1785, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37293161

RESUMO

Nasopharyngeal carcinoma (NPC) is clinically challenging due to the development of distant metastasis following initial therapy. Therefore, it is necessary to elucidate the mechanisms underlying metastases to develop novel therapeutic strategies. Nucleophosmin 1 (NPM1) has been directly linked to the development of human tumors and may have both tumor-suppressing and oncogenic properties. Although NPM1 is often overexpressed in solid tumors of various histopathological origins, its specific function in mediating the development of NPC is still unknown. Here, we investigated the role of NPM1 in NPC and discovered that NPM1 was elevated in clinical NPC samples and served as a predictor of the worst prognosis in NPC patients. Furthermore, the upregulation of NPM1 promoted the migration and the cancer stemness of NPC both in vitro and in vivo. Mechanistic analyses revealed that the E3 ubiquitin ligase Mdm2 was recruited by NPM1 to induce the ubiquitination-mediated proteasomal degradation of p53. Ultimately, knockdown of NPM1 suppressed the stemness and EMT signals. In summation, this study demonstrated the role and the underlying molecular mechanism of NPM1 in NPC, providing the evidence for the clinical application of NPM1 as a therapeutic target for the treatment of patients with NPC.

11.
Proc Natl Acad Sci U S A ; 120(24): e2219404120, 2023 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-37276413

RESUMO

Nogo-66 receptor 1 (NgR1) binds a variety of structurally dissimilar ligands in the adult central nervous system to inhibit axon extension. Disruption of ligand binding to NgR1 and subsequent signaling can improve neuron outgrowth, making NgR1 an important therapeutic target for diverse neurological conditions such as spinal crush injuries and Alzheimer's disease. Human NgR1 serves as a receptor for mammalian orthoreovirus (reovirus), but the mechanism of virus-receptor engagement is unknown. To elucidate how NgR1 mediates cell binding and entry of reovirus, we defined the affinity of interaction between virus and receptor, determined the structure of the virus-receptor complex, and identified residues in the receptor required for virus binding and infection. These studies revealed that central NgR1 surfaces form a bridge between two copies of viral capsid protein σ3, establishing that σ3 serves as a receptor ligand for reovirus. This unusual binding interface produces high-avidity interactions between virus and receptor to prime early entry steps. These studies refine models of reovirus cell-attachment and highlight the evolution of viruses to engage multiple receptors using distinct capsid components.


Assuntos
Orthoreovirus , Reoviridae , Animais , Humanos , Receptor Nogo 1/metabolismo , Ligação Viral , Proteínas Virais/metabolismo , Ligantes , Reoviridae/metabolismo , Orthoreovirus/metabolismo , Receptores Virais/metabolismo , Mamíferos/metabolismo
12.
Brief Bioinform ; 24(4)2023 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-37385595

RESUMO

Allergies have become an emerging public health problem worldwide. The most effective way to prevent allergies is to find the causative allergen at the source and avoid re-exposure. However, most of the current computational methods used to identify allergens were based on homology or conventional machine learning methods, which were inefficient and still had room to be improved for the detection of allergens with low homology. In addition, few methods based on deep learning were reported, although deep learning has been successfully applied to several tasks in protein sequence analysis. In the present work, a deep neural network-based model, called DeepAlgPro, was proposed to identify allergens. We showed its great accuracy and applicability to large-scale forecasts by comparing it to other available tools. Additionally, we used ablation experiments to demonstrate the critical importance of the convolutional module in our model. Moreover, further analyses showed that epitope features contributed to model decision-making, thus improving the model's interpretability. Finally, we found that DeepAlgPro was capable of detecting potential new allergens. Overall, DeepAlgPro can serve as powerful software for identifying allergens.


Assuntos
Aprendizado Profundo , Hipersensibilidade , Humanos , Alérgenos , Redes Neurais de Computação , Proteínas/metabolismo
13.
Clinics (Sao Paulo) ; 78: 100232, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37364352

RESUMO

BACKGROUND: This study aimed to evaluate the association between Monocyte Lymphocyte Ratio (MLR) and Abdominal Aortic Calcification (AAC) in adults over 40 years of age in the United States. METHODS: Data were collected from the 2013-2014 National Health and Nutrition Examination Survey (NHANES). AAC was quantified by the Kauppila score system based on dual-energy X-Ray absorptiometry. Severe AAC was defined as a total AAC score > 6. The lymphocyte count and monocyte count can be directly obtained from laboratory data files. Multivariable logistic regression models were used to determine the association between MLR and the AAC score and severe AAC. RESULTS: A total of 3,045 participants were included in the present study. After adjusting for multiple covariates, MLR was positively associated with higher AAC score (ß = 0.21, 95% CI 0.07, 0.34, p = 0.0032) and the odds of severe AAC increased by 14% per 0.1 unit increase in the MLR (OR = 1.14, 95% CI 1.00, 1.31, p = 0.0541). The Odds Ratio (OR) (95% CI) of severe AAC for participants in MLR tertile 3 was 1.88 (1.02, 3.47) compared with those in tertile 1 (p for trend = 0.0341). Subgroup analyses showed that a stronger association was detected in the elderly compared with non-elderly (p for interaction = 0.0346) and diabetes compared with non-diabetes (borderline significant p for interaction = 0.0578). CONCLUSION: In adults in the United States, MLR was associated with higher AAC scores and a higher probability of severe AAC. MLR may become a promising tool to predict the risk of AAC.


Assuntos
Doenças da Aorta , Calcificação Vascular , Humanos , Adulto , Estados Unidos/epidemiologia , Pessoa de Meia-Idade , Inquéritos Nutricionais , Estudos Transversais , Monócitos , Calcificação Vascular/diagnóstico por imagem , Linfócitos , Aorta Abdominal/diagnóstico por imagem , Fatores de Risco , Doenças da Aorta/diagnóstico por imagem
14.
BMC Musculoskelet Disord ; 24(1): 219, 2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-36959614

RESUMO

BACKGROUND AND OBJECTIVE: The aim of this study was to elucidate the clinical and myopathological characteristics of patients with anti-signal recognition particle (SRP) positive immune-mediated necrotizing myopathy (IMNM) overlap Sjogren's syndrome (SS). MATERIALS AND METHODS: We retrospectively analyzed the data of anti-SRP positive IMNM patients admitted in the Neurology Department of Tongji Hospital between January 2011 to December 2020. Patients were divided into two groups: anti-SRP IMNM overlap SS group and anti-SRP IMNM control group. The clinical features, laboratory results, histological features, treatment, and prognosis were compared between the two groups. RESULTS: A total of 30 patients with anti-SRP IMNM were included, including six anti-SRP IMNM overlap SS patients (two males, four females), with a median age of 39 years, and 24 anti-SRP IMNM patients (ten males, fourteen females), with a median age of 46 years. The anti-SRP IMNM overlap SS group had a lower prevalence of muscle atrophy (0 vs 50%, p = 0.019), and a higher prevalence of extramuscular manifestations, including cardiac abnormalities and ILD (Interstitial lung disease). CD4 + and CD68 + inflammatory infiltrations were significantly increased in anti-SRP IMNM overlap SS patients, with an increased presence of CD4 + cells in both necrotic(p = 0.023) and endomysial areas (p = 0.013), and more CD68 + cells (p = 0.016) infiltrated the endomysial area. Deposition of membrane attack complex (MAC) on sarcolemma (p = 0.013) was more commonly seen in the anti-SRP IMNM overlap SS group. CONCLUSION: Our data revealed that anti-SRP IMNM-SS overlap patients may present with milder muscular manifestation, but worse extramuscular manifestations compared to anti-SRP IMNM patients without SS. CD4 + and CD68 + inflammatory infiltrations and MAC deposition were remarkably increased in anti-SRP IMNM-SS overlap patients.


Assuntos
Doenças Autoimunes , Doenças Musculares , Miosite , Síndrome de Sjogren , Masculino , Feminino , Humanos , Adulto , Pessoa de Meia-Idade , Músculo Esquelético/patologia , Síndrome de Sjogren/diagnóstico , Partícula de Reconhecimento de Sinal , Estudos Retrospectivos , Doenças Musculares/diagnóstico , Doenças Musculares/patologia , Miosite/tratamento farmacológico , Necrose/patologia , Autoanticorpos , Doenças Autoimunes/patologia
15.
J Biol Chem ; 299(5): 104630, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36963495

RESUMO

CTX-M ß-lactamases are a widespread source of resistance to ß-lactam antibiotics in Gram-negative bacteria. These enzymes readily hydrolyze penicillins and cephalosporins, including oxyimino-cephalosporins such as cefotaxime. To investigate the preference of CTX-M enzymes for cephalosporins, we examined eleven active-site residues in the CTX-M-14 ß-lactamase model system by alanine mutagenesis to assess the contribution of the residues to catalysis and specificity for the hydrolysis of the penicillin, ampicillin, and the cephalosporins cephalothin and cefotaxime. Key active site residues for class A ß-lactamases, including Lys73, Ser130, Asn132, Lys234, Thr216, and Thr235, contribute significantly to substrate binding and catalysis of penicillin and cephalosporin substrates in that alanine substitutions decrease both kcat and kcat/KM. A second group of residues, including Asn104, Tyr105, Asn106, Thr215, and Thr216, contribute only to substrate binding, with the substitutions decreasing only kcat/KM. Importantly, calculating the average effect of a substitution across the 11 active-site residues shows that the most significant impact is on cefotaxime hydrolysis while ampicillin hydrolysis is least affected, suggesting the active site is highly optimized for cefotaxime catalysis. Furthermore, we determined X-ray crystal structures for the apo-enzymes of the mutants N106A, S130A, N132A, N170A, T215A, and T235A. Surprisingly, in the structures of some mutants, particularly N106A and T235A, the changes in structure propagate from the site of substitution to other regions of the active site, suggesting that the impact of substitutions is due to more widespread changes in structure and illustrating the interconnected nature of the active site.


Assuntos
Domínio Catalítico , Cefalosporinas , Resistência a Medicamentos , Escherichia coli , beta-Lactamases , Ampicilina/metabolismo , Ampicilina/farmacologia , beta-Lactamases/química , beta-Lactamases/metabolismo , Catálise , Domínio Catalítico/genética , Cefotaxima/metabolismo , Cefotaxima/farmacologia , Cefalosporinas/metabolismo , Cefalosporinas/farmacologia , Resistência a Medicamentos/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Mutagênese , Penicilinas/metabolismo , Penicilinas/farmacologia , beta-Lactamas/metabolismo , Modelos Moleculares , Estrutura Terciária de Proteína
16.
Commun Biol ; 6(1): 35, 2023 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-36635385

RESUMO

CTX-M ß-lactamases are prevalent antibiotic resistance enzymes and are notable for their ability to rapidly hydrolyze the extended-spectrum cephalosporin, cefotaxime. We hypothesized that the active site sequence requirements of CTX-M-mediated hydrolysis differ between classes of ß-lactam antibiotics. Accordingly, we use codon randomization, antibiotic selection, and deep sequencing to determine the CTX-M active-site residues required for hydrolysis of cefotaxime and the penicillin, ampicillin. The study reveals positions required for hydrolysis of all ß-lactams, as well as residues controlling substrate specificity. Further, CTX-M enzymes poorly hydrolyze the extended-spectrum cephalosporin, ceftazidime. We further show that the sequence requirements for ceftazidime hydrolysis follow those of cefotaxime, with the exception that key active-site omega loop residues are not required, and may be detrimental, for ceftazidime hydrolysis. These results provide insights into cephalosporin hydrolysis and demonstrate that changes to the active-site omega loop are likely required for the evolution of CTX-M-mediated ceftazidime resistance.


Assuntos
Ceftazidima , Escherichia coli , beta-Lactamases , beta-Lactamases/metabolismo , Catálise , Cefotaxima/farmacologia , Ceftazidima/farmacologia , Cefalosporinas/farmacologia , Resistência Microbiana a Medicamentos , Escherichia coli/metabolismo , Monobactamas , Especificidade por Substrato
17.
Curr Mol Pharmacol ; 16(8): 894-904, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36717994

RESUMO

AIMS AND OBJECTIVE: This study aimed to unveil the specific function of lncRNA BBOX1 antisense RNA 1 (BBOX1-AS1) in ESCC cells and the underlying regulatory mechanism. BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a deadly disease. Molecular mechanisms essential to ESCC development and progression require in-depth investigation. Long noncoding RNAs (lncRNAs) have been suggested as crucial effectors in modulating tumor growth. METHODS: RT-qPCR and western blot examined the expression of genes and proteins of concern, respectively. Colony formation and EdU assays assessed the changes in cell proliferation. Sphere formation assay also detected the stemness of ESCC cells. Bioinformatics prediction, along with mechanistic assays (FISH, Subcellular fractionation, RNA pull-down, RIP, and luciferase reporter), was conducted to explore the gene interactions and regulatory relationship. RESULTS: BBOX1-AS1 was observed to be aberrantly up-regulated in ESCC tissues and cell lines. BBOX1-AS1 depletion exerted suppressive impacts on ESCC cell proliferation and stemness, while BBOX1-AS1 overexpression led to the opposite consequences. Moreover, BBOX1-AS1 was verified to activate Hedgehog signaling pathway via up-regulating PTCH1, and BBOX1-AS1 could sponge miR-506-5p to up-regulate EIF5A, thus stabilizing PTCH1 mRNA. Rescue experiments indicated that BBOX1-AS1 could affect ESCC cell proliferation and stemness via modulation on PTCH1. CONCLUSION: To conclude, BBOX1-AS1 activates Hedgehog signaling pathway to facilitate the proliferation and stemness of ESCC cells via miR-506-5p/EIF5A/PTCH1 axis.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , MicroRNAs , Humanos , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células/genética , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/patologia , Regulação Neoplásica da Expressão Gênica , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo
18.
Clinics ; 78: 100232, 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1506011

RESUMO

Abstract Background This study aimed to evaluate the association between Monocyte Lymphocyte Ratio (MLR) and Abdominal Aortic Calcification (AAC) in adults over 40 years of age in the United States. Methods Data were collected from the 2013-2014 National Health and Nutrition Examination Survey (NHANES). AAC was quantified by the Kauppila score system based on dual-energy X-Ray absorptiometry. Severe AAC was defined as a total AAC score > 6. The lymphocyte count and monocyte count can be directly obtained from laboratory data files. Multivariable logistic regression models were used to determine the association between MLR and the AAC score and severe AAC. Results A total of 3,045 participants were included in the present study. After adjusting for multiple covariates, MLR was positively associated with higher AAC score (β = 0.21, 95% CI 0.07, 0.34, p = 0.0032) and the odds of severe AAC increased by 14% per 0.1 unit increase in the MLR (OR = 1.14, 95% CI 1.00, 1.31, p = 0.0541). The Odds Ratio (OR) (95% CI) of severe AAC for participants in MLR tertile 3 was 1.88 (1.02, 3.47) compared with those in tertile 1 (p for trend = 0.0341). Subgroup analyses showed that a stronger association was detected in the elderly compared with non-elderly (p for interaction = 0.0346) and diabetes compared with non-diabetes (borderline significant p for interaction = 0.0578). Conclusion In adults in the United States, MLR was associated with higher AAC scores and a higher probability of severe AAC. MLR may become a promising tool to predict the risk of AAC.

19.
Development ; 149(23)2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36448532

RESUMO

Undescended testis (UDT) affects 6% of male births. Despite surgical correction, some men with unilateral UDT may experience infertility with the contralateral descended testis (CDT) showing no A-dark spermatogonia. To improve our understanding of the etiology of infertility in UDT, we generated a novel murine model of left unilateral UDT. Gubernaculum-specific Wnt4 knockout (KO) mice (Wnt4-cKO) were generated using retinoic acid receptor ß2-cre mice and were found to have a smaller left-unilateral UDT. Wnt4-cKO mice with abdominal UDT had an increase in serum follicle-stimulating hormone and luteinizing hormone and an absence of germ cells in the undescended testicle. Wnt4-cKO mice with inguinal UDT had normal hormonal profiles, and 50% of these mice had no sperm in the left epididymis. Wnt4-cKO mice had fertility defects and produced 52% fewer litters and 78% fewer pups than control mice. Wnt4-cKO testes demonstrated increased expression of estrogen receptor α and SOX9, upregulation of female gonadal genes, and a decrease in male gonadal genes in both CDT and UDT. Several WNT4 variants were identified in boys with UDT. The presence of UDT and fertility defects in Wnt4-cKO mice highlights the crucial role of WNT4 in testicular development.


Assuntos
Criptorquidismo , Infertilidade , Feminino , Masculino , Humanos , Camundongos , Animais , Gubernáculo , Criptorquidismo/genética , Fertilidade/genética , Espermatogônias , Camundongos Knockout , Proteína Wnt4/genética
20.
Proc Natl Acad Sci U S A ; 119(46): e2214569119, 2022 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-36343225

RESUMO

Immunocyte infiltration and cytotoxicity play critical roles in both inflammation and immunotherapy. However, current cancer immunotherapy screening methods overlook the capacity of the T cells to penetrate the tumor stroma, thereby significantly limiting the development of effective treatments for solid tumors. Here, we present an automated high-throughput microfluidic platform for simultaneous tracking of the dynamics of T cell infiltration and cytotoxicity within the 3D tumor cultures with a tunable stromal makeup. By recourse to a clinical tumor-infiltrating lymphocyte (TIL) score analyzer, which is based on a clinical data-driven deep learning method, our platform can evaluate the efficacy of each treatment based on the scoring of T cell infiltration patterns. By screening a drug library using this technology, we identified an epigenetic drug (lysine-specific histone demethylase 1 inhibitor, LSD1i) that effectively promoted T cell tumor infiltration and enhanced treatment efficacy in combination with an immune checkpoint inhibitor (anti-PD1) in vivo. We demonstrated an automated system and strategy for screening immunocyte-solid tumor interactions, enabling the discovery of immuno- and combination therapies.


Assuntos
Aprendizado Profundo , Neoplasias , Humanos , Microfluídica/métodos , Detecção Precoce de Câncer , Imunoterapia/métodos , Linfócitos do Interstício Tumoral , Fatores Imunológicos , Neoplasias/tratamento farmacológico , Microambiente Tumoral
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