-
STAR Protocols Jun 2024A gene-rescue experiment under a mutant background is essential to clarify gene function and the resulting biological potential in vivo. Here, we present a protocol for...
A gene-rescue experiment under a mutant background is essential to clarify gene function and the resulting biological potential in vivo. Here, we present a protocol for determining the change in interferon response by microinjecting plasmids into one-cell-stage zebrafish embryos. We describe steps for comparing the resistance potential to virus infection in wild-type and knockout zebrafish larvae following plasmid microinjection. We then detail how to link the enhanced interferon immunity to the improved resistance in knockout zebrafish larvae by gene-rescue experiments. For complete details on the use and execution of this protocol, please refer to Qu et al..
PubMed: 38941183
DOI: 10.1016/j.xpro.2024.103156 -
Cancer Science Jun 2024Osimertinib induces a marked response in non-small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) gene mutations. However, acquired...
Osimertinib induces a marked response in non-small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) gene mutations. However, acquired resistance to osimertinib remains an inevitable problem. In this study, we aimed to investigate osimertinib-resistant mechanisms and evaluate the combination therapy of afatinib and chemotherapy. We established osimertinib-resistant cell lines (PC-9-OR and H1975-OR) from EGFR-mutant lung adenocarcinoma cell lines PC-9 and H1975 by high exposure and stepwise method. Combination therapy of afatinib plus carboplatin (CBDCA) and pemetrexed (PEM) was effective in both parental and osimertinib-resistant cells. We found that expression of thrombospondin-1 (TSP-1) was upregulated in resistant cells using cDNA microarray analysis. We demonstrated that TSP-1 increases the expression of matrix metalloproteinases through integrin signaling and promotes tumor invasion in both PC-9-OR and H1975-OR, and that epithelial-to-mesenchymal transition (EMT) was involved in H1975-OR. Afatinib plus CBDCA and PEM reversed TSP-1-induced invasion ability and EMT changes in resistant cells. In PC-9-OR xenograft mouse models (five female Balb/c-Nude mice in each group), combination therapy strongly inhibited tumor growth compared with afatinib monotherapy (5 mg/kg, orally, five times per week) or CBDCA (75 mg/kg, intraperitoneally, one time per week) + PEM (100 mg/kg, intraperitoneally, one time per week) over a 28-day period. These results suggest that the combination of afatinib plus CBDCA and PEM, which effectively suppresses TSP-1 expression, may be a promising option in EGFR-mutated NSCLC patients after the acquisition of osimertinib resistance.
PubMed: 38941131
DOI: 10.1111/cas.16199 -
Metabolomics : Official Journal of the... Jun 2024Exploring metabolic changes within host E. coli through an untargeted metabolomic study of T7L variants overexpression to optimize engineered endolysins for...
INTRODUCTION
Exploring metabolic changes within host E. coli through an untargeted metabolomic study of T7L variants overexpression to optimize engineered endolysins for clinical/therapeutic use.
AIM AND OBJECTIVE
This study aims to assess the impact of overexpressing T7L variants on the metabolic profiles of E. coli. The two variants considered include T7L-H37A, which has enhanced lytic activity compared to its wild-type protein, and T7L-H48K, a dead mutant with no significant activity.
METHODS
H NMR-based metabolomics was employed to compare the metabolic profiles of E. coli cells overexpressing T7L wild-type protein and its variants.
RESULTS
Overexpression of the T7L wild-type (T7L-WT) protein and its variants (T7L-H48K and T7L-H37A) was compared to RNAP overexpression in E. coli cells using H NMR-based metabolomics, analyzing a total of 75 annotated metabolites, including organic acids, amino acids, sugars, and nucleic acids. The results showed distinct clustering patterns for the two T7L variant groups compared with the WT, in which the dead mutant (H48K) group showed clustering close to that of RNAP. Pathway impact analysis revealed different effects of T7L variants on E. coli metabolic profiles, with T7L-H48K showing minimal alterations in energy and amino acid pathways linked to osmotic stress compared to noticeable alterations in these pathways for both T7L-H37A and T7L-WT.
CONCLUSIONS
This study uncovered distinct metabolic fingerprints when comparing the overexpression of active and inactive mutants of T7L lytic enzymes in E. coli cells. These findings could contribute to the optimization and enhancement of suitable endolysins as potential alternatives to antibiotics.
Topics: Escherichia coli; Metabolome; Metabolomics; Viral Proteins; Bacteriophage T7; Mutation; DNA-Directed RNA Polymerases
PubMed: 38941046
DOI: 10.1007/s11306-024-02133-y -
Gastric Cancer : Official Journal of... Jun 2024The contribution of the tumor microenvironment and extracellular matrix to the aggressive biology of Gastric Cancer (GC) has been recently characterized; however, the...
BACKGROUND
The contribution of the tumor microenvironment and extracellular matrix to the aggressive biology of Gastric Cancer (GC) has been recently characterized; however, the role of EMILIN-1 in this context is unknown. EMILIN-1 is an essential structural element for the maintenance of lymphatic vessel (LV) integrity and displays anti-proliferative properties as demonstrated in skin and colon cancer. Given the key role of LVs in GC progression, the aim of this study was to investigate the role of EMILIN-1 in GC mouse models.
METHODS
We used the syngeneic YTN16 cells which were injected subcutaneously and intraperitoneally in genetically modified EMILIN-1 mice. In alternative, carcinogenesis was induced using N-Methyl-N-nitrosourea (MNU). Mouse-derived samples and human biopsies were analyzed by IHC and IF to the possible correlation between EMILIN-1 expression and LV pattern.
RESULTS
Transgenic mice developed tumors earlier compared to WT animals. 20 days post-injection tumors developed in EMILIN-1 mutant mice were larger and displayed a significant increase of lymphangiogenesis. Treatment of transgenic mice with MNU associated with an increased number of tumors, exacerbated aggressive lesions and higher levels of LV abnormalities. A significant correlation between the levels of EMILIN-1 and podoplanin was detected also in human samples, confirming the results obtained with the pre-clinical models.
CONCLUSIONS
This study demonstrates for the first time that loss of EMILIN-1 in GC leads to lymphatic dysfunction and proliferative advantages that sustain tumorigenesis, and assess the use of our animal model as a valuable tool to verify the fate of GC upon loss of EMILIN-1.
PubMed: 38941035
DOI: 10.1007/s10120-024-01528-z -
BdRCN4, a Brachypodium distachyon TFL1 homologue, is involved in regulation of apical meristem fate.Plant Molecular Biology Jun 2024In higher plants, the shift from vegetative to reproductive development is governed by complex interplay of internal and external signals. TERMINALFLOWER1 (TFL1) plays a...
In higher plants, the shift from vegetative to reproductive development is governed by complex interplay of internal and external signals. TERMINALFLOWER1 (TFL1) plays a crucial role in the regulation of flowering time and inflorescence architecture in Arabidopsis thaliana. This study aimed to explore the function of BdRCN4, a homolog of TFL1 in Brachypodium distachyon, through functional analyses in mutant and transgenic plants. The results revealed that overexpression of BdRCN4 in B. distachyon leads to an extended vegetative phase and reduced production of spikelets. Similar results were found in A. thaliana, where constitutive expression of BdRCN4 promoted a delay in flowering time, followed by the development of hypervegetative shoots, with no flowers or siliques produced. Our results suggest that BdRCN4 acts as a flowering repressor analogous to TFL1, negatively regulating AP1, but no LFY expression. To further validate this hypothesis, a 35S::LFY-GR co-transformation approach on 35::BdRCN4 lines was performed. Remarkably, AP1 expression levels and flower formation were restored to normal in co-transformed plants when treated with dexamethasone. Although further molecular studies will be necessary, the evidence in B. distachyon support the idea that a balance between LFY and BdRCN4/TFL1 seems to be essential for activating AP1 expression and initiating floral organ identity gene expression. This study also demonstrates interesting conservation through the molecular pathways that regulate flowering meristem transition and identity across the evolution of monocot and dicot plants.
Topics: Brachypodium; Meristem; Gene Expression Regulation, Plant; Plant Proteins; Flowers; Plants, Genetically Modified; Arabidopsis; Arabidopsis Proteins
PubMed: 38940986
DOI: 10.1007/s11103-024-01467-4 -
Membrane protein Bcsdr2 mediates biofilm integrity, hyphal growth and virulence of Botrytis cinerea.Applied Microbiology and Biotechnology Jun 2024Grey mould caused by Botrytis cinerea is a devastating disease responsible for large losses to agricultural production, and B. cinerea is a necrotrophic model fungal...
Grey mould caused by Botrytis cinerea is a devastating disease responsible for large losses to agricultural production, and B. cinerea is a necrotrophic model fungal plant pathogen. Membrane proteins are important targets of fungicides and hotspots in the research and development of fungicide products. Wuyiencin affects the permeability and pathogenicity of B. cinerea, parallel reaction monitoring revealed the association of membrane protein Bcsdr2, and the bacteriostatic mechanism of wuyiencin was elucidated. In the present work, we generated and characterised ΔBcsdr2 deletion and complemented mutant B. cinerea strains. The ΔBcsdr2 deletion mutants exhibited biofilm loss and dissolution, and their functional activity was illustrated by reduced necrotic colonisation on strawberry and grape fruits. Targeted deletion of Bcsdr2 also blocked several phenotypic defects in aspects of mycelial growth, conidiation and virulence. All phenotypic defects were restored by targeted gene complementation. The roles of Bcsdr2 in biofilms and pathogenicity were also supported by quantitative real-time RT-PCR results showing that phosphatidylserine decarboxylase synthesis gene Bcpsd and chitin synthase gene BcCHSV II were downregulated in the early stages of infection for the ΔBcsdr2 strain. The results suggest that Bcsdr2 plays important roles in regulating various cellular processes in B. cinerea. KEY POINTS: • The mechanism of wuyiencin inhibits B. cinerea is closely associated with membrane proteins. • Wuyiencin can downregulate the expression of the membrane protein Bcsdr2 in B. cinerea. • Bcsdr2 is involved in regulating B. cinerea virulence, growth and development.
Topics: Botrytis; Biofilms; Virulence; Hyphae; Plant Diseases; Fragaria; Fungal Proteins; Membrane Proteins; Vitis; Spores, Fungal; Gene Deletion
PubMed: 38940906
DOI: 10.1007/s00253-024-13238-8 -
Thyroid : Official Journal of the... Jun 2024Papillary thyroid cancer (PTC) and lymphocytic thyroiditis (LT) co-occur with a prevalence of about 30%. PTC harbouring BRAFV600E(PTC-BRAF) confers a worse prognosis,...
BACKGROUND
Papillary thyroid cancer (PTC) and lymphocytic thyroiditis (LT) co-occur with a prevalence of about 30%. PTC harbouring BRAFV600E(PTC-BRAF) confers a worse prognosis, but it is unclear if LT alters prognostic features and recurrence of PTC.
OBJECTIVE
We compared prevalence of PTC-BRAF with and without LT. The risk of adverse pathologic features in (i) PTC-BRAF, irrespective of LT status, was compared to (ii)PTC with LT, irrespective of BRAF status.
METHODS
We searched PubMed, Embase and Web of Science Core Collection for observational studies published from 2010 to June 2023 on adult patients with PTC. The search strategy yielded 47 studies with relevant data. Data of baseline characteristics, clinicopathological features and the quality assessment tool was extracted by two reviewers.
RESULTS
Of the 47 studies, 39 studies with a total cohort of 28 143, demonstrated the odds of PTC-BRAF was significantly lower in the presence on LT compared to its absence (OR 0.53, 95% CI: 0.48-0.58, p<0.00001). In PTC-BRAF patients, there was positive association of central neck nodal disease (CNND), PTC>1cm, extra-thyroidal extension, AJCC Stage 3-4 and multifocality with pooled OR 1.54 (95%CI:1.16-2.04), 1.14 (95%CI: 0.82- 1.58) , 1.66 (95%CI: 1.40-1.97), 1.53 (95% CI: 1.35-1.75) and 1.24 (95%CI: 1.11-1.40) respectively, compared to wild type PTC, irrespective of LT status. In the same studies, PTC with LT patients had lower pooled OR of 0.64 (95%CI: 0.51-0.81) for CNND, 0.83 (95%CI: 0.73 - 0.95) for PTC> 1cm, 0.71 (95%CI: 0.58-0.86) for ETE, 0.84 (95%CI: 0.75-0.94) for AJCC Stage 3-4 compared to PTC without LT, irrespective of BRAF status. PTC recurrence was not affected by BRAF or LT with pooled OR of 1.12 (95%CI: 0.66-1.90, p=0.67) and 0.60 (95%CI: 0.28-1.30, p=0.20) respectively. Similar results were seen with recurrence expressed as hazard ratio in this limited data-set.
CONCLUSION
The odds of PTC-BRAF is significantly lower in the presence of LT than without. PTC with LT, irrespective of BRAF status, was significantly associated with better prognostic factors. Further studies are required to evaluate if LT inhibits PTC-BRAF, and weather this is relevant to the role of immunotherapy in advanced thyroid cancer.
PubMed: 38940753
DOI: 10.1089/thy.2024.0142 -
MBio Jun 2024Inositol pyrophosphate 1,5-IP regulates expression of a fission yeast phosphate homeostasis regulon, comprising phosphate acquisition genes , , and , via its action as...
UNLABELLED
Inositol pyrophosphate 1,5-IP regulates expression of a fission yeast phosphate homeostasis regulon, comprising phosphate acquisition genes , , and , via its action as an agonist of precocious termination of transcription of the upstream lncRNAs that repress mRNA synthesis. 1,5-IP levels are dictated by a balance between the Asp1 N-terminal kinase domain that converts 5-IP to 1,5-IP and three inositol pyrophosphatases-the Asp1 C-terminal domain (a histidine acid phosphatase), Siw14 (a cysteinyl-phosphatase), and Aps1 (a Nudix enzyme). In this study, we report the biochemical and genetic characterization of Aps1 and an analysis of the effects of Asp1, Siw14, and Aps1 mutations on cellular inositol pyrophosphate levels. We find that Aps1's substrate repertoire embraces inorganic polyphosphates, 5-IP, 1-IP, and 1,5-IP. Aps1 displays a ~twofold preference for hydrolysis of 1-IP versus 5-IP and ∆ cells have twofold higher levels of 1-IP vis-à-vis wild-type cells. While neither Aps1 nor Siw14 is essential for growth, an ∆ ∆ double mutation is lethal on YES medium. This lethality is a manifestation of IP toxicosis, whereby excessive 1,5-IP drives derepression of leading to Tgp1-mediated uptake of glycerophosphocholine. We were able to recover an ∆ ∆ mutant on ePMGT medium lacking glycerophosphocholine and to suppress the severe growth defect of ∆ ∆ on YES by deleting . However, the severe growth defect of an ∆ strain could not be alleviated by deleting , suggesting that 1,5-IP levels in this double-pyrophosphatase mutant exceed a threshold beyond which overzealous termination affects other genes, which results in cytotoxicity.
IMPORTANCE
Repression of the fission yeast genes , , and by lncRNA-mediated interference is sensitive to changes in the metabolism of 1,5-IP, a signaling molecule that acts as an agonist of precocious lncRNA termination. 1,5-IP is formed by phosphorylation of 5-IP and catabolized by inositol pyrophosphatases from three distinct enzyme families: Asp1 (a histidine acid phosphatase), Siw14 (a cysteinyl phosphatase), and Aps1 (a Nudix hydrolase). This study entails a biochemical characterization of Aps1 and an analysis of how Asp1, Siw14, and Aps1 mutations impact growth and inositol pyrophosphate pools . Aps1 catalyzes hydrolysis of inorganic polyphosphates, 5-IP, 1-IP, and 1,5-IP , with a ~twofold preference for 1-IP over 5-IP. ∆ cells have twofold higher levels of 1-IP than wild-type cells. An ∆ ∆ double mutation is lethal because excessive 1,5-IP triggers derepression of , leading to toxic uptake of glycerophosphocholine.
PubMed: 38940614
DOI: 10.1128/mbio.01084-24 -
Antimicrobial Agents and Chemotherapy Jun 2024Intrinsic resistance to macrolides in Gram-negative bacteria is primarily attributed to the low permeability of the outer membrane, though the underlying genetic and...
Intrinsic resistance to macrolides in Gram-negative bacteria is primarily attributed to the low permeability of the outer membrane, though the underlying genetic and molecular mechanisms remain to be fully elucidated. Here, we used transposon directed insertion-site sequencing (TraDIS) to identify chromosomal non-essential genes involved in intrinsic resistance to a macrolide antibiotic, tilmicosin. We constructed two highly saturated transposon mutant libraries of >290,000 and >390,000 unique Tn5 insertions in a clinical enterotoxigenic strain (ETEC5621) and in a laboratory strain (K-12 MG1655), respectively. TraDIS analysis identified genes required for growth of ETEC5621 and MG1655 under 1/8 MIC ( = 15 and 16, respectively) and 1/4 MIC ( = 38 and 32, respectively) of tilmicosin. For both strains, 23 genes related to lipopolysaccharide biosynthesis, outer membrane assembly, the Tol-Pal system, efflux pump, and peptidoglycan metabolism were enriched in the presence of the antibiotic. Individual deletion of genes ( = 10) in the wild-type strains led to a 64- to 2-fold reduction in MICs of tilmicosin, erythromycin, and azithromycin, validating the results of the TraDIS analysis. Notably, deletion of or , which impairs the outer membrane, led to the most significant decreases in MICs of all three macrolides in ETEC5621. Our findings contribute to a genome-wide understanding of intrinsic macrolide resistance in , shedding new light on the potential role of the peptidoglycan layer. They also provide an proof of concept that can be sensitized to macrolides by targeting proteins maintaining the outer membrane such as SurA and WaaG.
PubMed: 38940570
DOI: 10.1128/aac.00452-24 -
Applied and Environmental Microbiology Jun 2024Although functional studies on carbohydrate-binding module (CBM) have been carried out extensively, the role of tandem CBMs in the enzyme containing multiple catalytic...
UNLABELLED
Although functional studies on carbohydrate-binding module (CBM) have been carried out extensively, the role of tandem CBMs in the enzyme containing multiple catalytic domains (CDs) is unclear. Here, we identified a multidomain enzyme (Lc25986) with a novel modular structure from lignocellulolytic bacterial consortium. It consists of a mannanase domain, two CBM65 domains (LcCBM65-1/LcCBM65-2), and an esterase domain. To investigate CBM function and domain interactions, full-length Lc25986 and its variants were constructed and used for enzymatic activity, binding, and bioinformatic analyses. The results showed that LcCBM65-1 and LcCBM65-2 both bind mannan and xyloglucan but not cellulose or β-1,3-1,4-glucan, which differs from the ligand specificity of reported CBM65s. Compared to LcCBM65-2, LcCBM65-1 showed a stronger ligand affinity and a preference for acetylation sites. Both CBM65s stimulated the enzymatic activities of their respective neighboring CDs against acetylated mannan, but did not contribute to the activities of the distal CDs. The time course of mannan hydrolysis indicated that the full-length Lc25986 was more effective in the complete degradation of mixed acetyl/non-acetyl substrates than the mixture of single-CD mutants. When acting on complex substrates, LcCBM65-1 not only improved the enzymatic activity of the mannanase domain, but also directed the esterase domain to the acetylated polysaccharides. LcCBM65-2 adopted a low affinity to reduce interference with the catalysis of the mannanase domain. These results demonstrate the importance of CBMs for the synergism between the two CDs of a multidomain enzyme and suggest that they contribute to the adequate degradation of complex substrates such as plant cell walls.
IMPORTANCE
Lignocellulolytic enzymes, particularly those of bacterial origin, often harbor multiple carbohydrate-binding modules (CBMs). However, the function of CBM multivalency remains poorly understood. This is especially true for enzymes that contain more than one catalytic domain (CD), as the interactions between CDs, CBMs, and CDs and CBMs can be complex. Our research demonstrates that homogeneous CBMs can have distinct functions in a multimodular enzyme. The tandem CBMs coordinate the CDs in catalytic conflict through their differences in binding affinity, ligand preference, and arrangement within the full-length enzyme. Additionally, although the synergism between mannanase and esterase is widely acknowledged, our study highlights the benefits of integrating the two enzymes into a single entity for the degradation of complex substrates. In summary, these findings enhance our understanding of the intra-synergism of a multimodular enzyme and emphasize the significance of multiple CBMs in this context.
PubMed: 38940565
DOI: 10.1128/aem.00888-24