Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 349
Filtrar
1.
Phys Rev Lett ; 132(17): 176302, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38728705

RESUMO

Compared with conventional topological insulator that carries topological state at its boundaries, the higher-order topological insulator exhibits lower-dimensional gapless boundary states at its corners and hinges. Leveraging the form similarity between Schrödinger equation and diffusion equation, research on higher-order topological insulators has been extended from condensed matter physics to thermal diffusion. Unfortunately, all the corner states of thermal higher-order topological insulator reside within the band gap. Another kind of corner state, which is embedded in the bulk states, has not been realized in pure diffusion systems so far. Here, we construct higher-dimensional Su-Schrieffer-Heeger models based on sphere-rod structure to elucidate these corner states, which we term "in-bulk corner states." Because of the anti-Hermitian properties of diffusive Hamiltonian, we investigate the thermal behavior of these corner states through theoretical calculation, simulation, and experiment. Furthermore, we study the different thermal behaviors of in-bulk corner state and in-gap corner state. Our results would open a different gate for diffusive topological states and provide a distinct application for efficient heat dissipation.

2.
Cell Death Dis ; 15(5): 335, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38744853

RESUMO

PTENα/ß, two variants of PTEN, play a key role in promoting tumor growth by interacting with WDR5 through their N-terminal extensions (NTEs). This interaction facilitates the recruitment of the SET1/MLL methyltransferase complex, resulting in histone H3K4 trimethylation and upregulation of oncogenes such as NOTCH3, which in turn promotes tumor growth. However, the molecular mechanism underlying this interaction has remained elusive. In this study, we determined the first crystal structure of PTENα-NTE in complex with WDR5, which reveals that PTENα utilizes a unique binding motif of a sequence SSSRRSS found in the NTE domain of PTENα/ß to specifically bind to the WIN site of WDR5. Disruption of this interaction significantly impedes cell proliferation and tumor growth, highlighting the potential of the WIN site inhibitors of WDR5 as a way of therapeutic intervention of the PTENα/ß associated cancers. These findings not only shed light on the important role of the PTENα/ß-WDR5 interaction in carcinogenesis, but also present a promising avenue for developing cancer treatments that target this pathway.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular , PTEN Fosfo-Hidrolase , PTEN Fosfo-Hidrolase/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/química , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/química , Animais , Camundongos , Neoplasias/genética , Neoplasias/patologia , Neoplasias/metabolismo , Proliferação de Células/genética , Progressão da Doença , Ligação Proteica , Linhagem Celular Tumoral , Camundongos Nus , Histona-Lisina N-Metiltransferase/metabolismo , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/química , Domínios Proteicos , Motivos de Aminoácidos
3.
Theranostics ; 14(6): 2345-2366, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38646645

RESUMO

Rationale: Primordial follicles are limited in number and cannot be regenerated, dormant primordial follicles cannot be reversed once they enter a growth state. Therefore, the length of the female reproductive lifespan depends on the orderly progression and selective activation of primordial follicles, the mechanism of which remains unclear. Methods: We used human ovarian cortical biopsy specimens, granulosa cells from diminished ovarian reserve (DOR) patients, Hdac6-overexpressing transgenic mouse model, and RNA sequencing to analyze the crucial roles of histone deacetylase 6 (HDAC6) in fertility preservation and primordial follicle activation. Results: In the present study, we found that HDAC6 was highly expressed in most dormant primordial follicles. The HDAC6 expression was reduced accompanying reproductive senescence in human and mouse ovaries. Overexpression of Hdac6 delayed the rate of primordial follicle activation, thereby prolonging the mouse reproductive lifespan. Short-term inhibition of HDAC6 promoted primordial follicle activation and follicular development in humans and mice. Mechanism studies revealed that HDAC6 directly interacted with NGF, reducing acetylation modification of NGF and thereby accelerating its ubiquitination degradation. Consequently, the reduced NGF protein level maintained the dormancy of primordial follicles. Conclusions: The physiological significance of the high expression of HDAC6 in most primordial follicles is to reduce NGF expression and prevent primordial follicle activation to maintain female fertility. Reduced HDAC6 expression increases NGF expression in primordial follicles, activating their development and contributing to reproduction. Our study provides a clinical reference value for fertility preservation.


Assuntos
Desacetilase 6 de Histona , Camundongos Transgênicos , Fator de Crescimento Neural , Folículo Ovariano , Ubiquitinação , Animais , Feminino , Humanos , Camundongos , Acetilação , Células da Granulosa/metabolismo , Desacetilase 6 de Histona/metabolismo , Desacetilase 6 de Histona/genética , Fator de Crescimento Neural/metabolismo , Folículo Ovariano/metabolismo
4.
Acta Pharmacol Sin ; 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622288

RESUMO

Cancer cells largely rely on aerobic glycolysis or the Warburg effect to generate essential biomolecules and energy for their rapid growth. The key modulators in glycolysis including glucose transporters and enzymes, e.g. hexokinase 2, enolase 1, pyruvate kinase M2, lactate dehydrogenase A, play indispensable roles in glucose uptake, glucose consumption, ATP generation, lactate production, etc. Transcriptional regulation and post-translational modifications (PTMs) of these critical modulators are important for signal transduction and metabolic reprogramming in the glycolytic pathway, which can provide energy advantages to cancer cell growth. In this review we recapitulate the recent advances in research on glycolytic modulators of cancer cells and analyze the strategies targeting these vital modulators including small-molecule inhibitors and microRNAs (miRNAs) for targeted cancer therapy. We focus on the regulation of the glycolytic pathway at the transcription level (e.g., hypoxia-inducible factor 1, c-MYC, p53, sine oculis homeobox homolog 1, N6-methyladenosine modification) and PTMs (including phosphorylation, methylation, acetylation, ubiquitination, etc.) of the key regulators in these processes. This review will provide a comprehensive understanding of the regulation of the key modulators in the glycolytic pathway and might shed light on the targeted cancer therapy at different molecular levels.

6.
World J Gastrointest Surg ; 16(3): 966-973, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38577088

RESUMO

BACKGROUND: Colorectal cavernous hemangioma is a rare vascular malformation resulting in recurrent lower gastrointestinal hemorrhage, and can be misinterpreted as colitis. Surgical resection is currently the mainstay of treatment, with an emphasis on sphincter preservation. CASE SUMMARY: We present details of two young patients with a history of persistent hematochezia diagnosed with colorectal cavernous hemangioma by endoscopic ultrasound (EUS). Cavernous hemangioma was relieved by several EUS-guided lauromacrogol injections and the patients achieved favorable clinical prognosis. CONCLUSION: Multiple sequential EUS-guided injections of lauromacrogol is a safe, effective, cost-efficient, and minimally invasive alternative for colorectal cavernous hemangioma.

7.
Biotechnol Bioeng ; 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38595326

RESUMO

Pathogenic bacterial membrane proteins (MPs) are a class of vaccine and antibiotic development targets with widespread clinical application. However, the inherent hydrophobicity of MPs poses a challenge to fold correctly in living cells. Herein, we present a comprehensive method to improve the soluble form of MP antigen by rationally designing multi-epitope chimeric antigen (ChA) and screening two classes of protein-assisting folding element. The study uses a homologous protein antigen as a functional scaffold to generate a ChA possessing four epitopes from transferrin-binding protein A of Glaesserella parasuis. Our engineered strain, which co-expresses P17 tagged-ChA and endogenous chaperones groEL-ES, yields a 0.346 g/L highly soluble ChA with the property of HPS-positive serum reaction. Moreover, the protein titer of ChA reaches 4.27 g/L with >90% soluble proportion in 5-L bioreactor, which is the highest titer reported so far. The results highlight a timely approach to design and improve the soluble expression of MP antigen in industrially viable applications.

8.
Nat Commun ; 15(1): 2169, 2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-38461277

RESUMO

Extensive investigations on the moiré magic angle in twisted bilayer graphene have unlocked the emerging field-twistronics. Recently, its optics analogue, namely opto-twistronics, further expands the potential universal applicability of twistronics. However, since heat diffusion neither possesses the dispersion like photons nor carries the band structure as electrons, the real magic angle in electrons or photons is ill-defined for heat diffusion, making it elusive to understand or design any thermal analogue of magic angle. Here, we introduce and experimentally validate the twisted thermotics in a twisted diffusion system by judiciously tailoring thermal coupling, in which twisting an analog thermal magic angle would result in the function switching from cloaking to concentration. Our work provides insights for the tunable heat diffusion control, and opens up an unexpected branch for twistronics -- twisted thermotics, paving the way towards field manipulation in twisted configurations including but not limited to fluids.

9.
Biotechnol J ; 19(3): e2300650, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38479990

RESUMO

S-Adenosyl-L-methionine (SAM) is a substrate for many enzyme-catalyzed reactions and provides methyl groups in numerous biological methylations, and thus has vast applications in the agriculture and medical field. Saccharomyces cerevisiae has been engineered as a platform with significant potential for producing SAM, but the current production has room for improvement. Thus, a method that consists of a series of metabolic engineering strategies was established in this study. These strategies included enhancing SAM synthesis, increasing ATP supply, down-regulating SAM metabolism, and down-regulating competing pathway. After combinatorial metabolic engineering, Bayesian optimization was conducted on the obtained strain C262P6S to optimize the fermentation medium. A final yield of 2972.8 mg·L-1 at 36 h with 29.7% of the L-Met conversion rate in the shake flask was achieved, which was 26.3 times higher than that of its parent strain and the highest reported production in the shake flask to date. This paper establishes a feasible foundation for the construction of SAM-producing strains using metabolic engineering strategies and demonstrates the effectiveness of Bayesian optimization in optimizing fermentation medium to enhance the generation of SAM.


Assuntos
Metionina , S-Adenosilmetionina , Metionina/metabolismo , S-Adenosilmetionina/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Engenharia Metabólica/métodos , Teorema de Bayes , Fermentação , Racemetionina/metabolismo
10.
Biomed Pharmacother ; 172: 116259, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38359488

RESUMO

Gastric cancer is a highly metastatic malignant tumor with high morbidity and mortality globally. Recent studies reported that sulfonamide derivatives such as indisulam exhibited inhibitory effects on the viability and migration of cancer cells. However, multiple clinical trials revealed that indisulam did not significantly prevent cancer progression due to metastasis and drug resistance. Therefore, it is necessary to discover new potent derivatives to explore alternative therapeutic strategies. Here, we synthesize multiple indisulam derivatives and examine their inhibitory effects on the viability and migration of gastric cancer cells. Among them, compounds SR-3-65 and WXM-1-170 exhibit better inhibitory effects on the migration of gastric cancer cells than indisulam. Mechanistically, we discover that they could attenuate the PI3K/AKT/GSK-3ß/ß-catenin signaling pathway and lead to the suppression of epithelial-to-mesenchymal transition (EMT)-related transcription factors. The influence of SR-3-65 on the migration of gastric cancer cells is blocked by the PI3K inhibitor LY294002 while SR-3-65 and WXM-1-170 reverse the effect of PI3K activator 740 Y-P on the migration of gastric cancer cells. Molecular docking and molecular dynamics simulation further confirm that PI3K is the target of SR-3-65. Our study unveils a novel mechanism by which SR-3-65 and WXM-1-170 inhibit the migration of gastric cancer cells. Together with the previous discovery, we reveal that subtle structural change in indisulam results in a striking switch on the molecular targets and their associated signaling pathways for the inhibition of the migration of gastric cancer cells. These findings might provide informative insights for the development of targeted therapy for gastric cancer.


Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Linhagem Celular Tumoral , Fosfatidilinositol 3-Quinases/metabolismo , Glicogênio Sintase Quinase 3 beta , Simulação de Acoplamento Molecular , Sulfonamidas
11.
Chin Herb Med ; 16(1): 106-112, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38375049

RESUMO

Objective: Anemoside B4 (AB4), the most abundant triterpenoidal saponin isolated from Pulsatilla chinensis, inhibited influenza virus FM1 or Klebsiella pneumoniae-induced pneumonia. However, the anti-SARS-CoV-2 effect of AB4 has not been unraveled. Therefore, this study aimed to determine the antiviral activity and potential mechanism of AB4 in inhibiting human coronavirus SARS-CoV-2 in vivo and in vitro. Methods: The cytotoxicity of AB4 was evaluated using the Cell Counting Kit-8 (CCK8) assay. SARS-CoV-2 infected HEK293T, HPAEpiC, and Vero E6 cells were used for in vitro assays. The antiviral effect of AB4 in vivo was evaluated by SARS-CoV-2-infected hACE2-IRES-luc transgenic mouse model. Furthermore, label-free quantitative proteomics and bioinformatic analysis were performed to explore the potential antiviral mechanism of action of AB4. Type I IFN signaling-associated proteins were assessed using Western blotting or immumohistochemical staining. Results: The data showed that AB4 reduced the propagation of SARS-CoV-2 along with the decreased Nucleocapsid protein (N), Spike protein (S), and 3C-like protease (3CLpro) in HEK293T cells. In vivo antiviral activity data revealed that AB4 inhibited viral replication and relieved pneumonia in a SARS-CoV-2 infected mouse model. We further disclosed that the antiviral activity of AB4 was associated with the enhanced interferon (IFN)-ß response via the activation of retinoic acid-inducible gene I (RIG-1) like receptor (RLP) pathways. Additionally, label-free quantitative proteomic analyses discovered that 17 proteins were significantly altered by AB4 in the SARS-CoV-2 coronavirus infections cells. These proteins mainly clustered in RNA metabolism. Conclusion: Our results indicated that AB4 inhibited SARS-CoV-2 replication through the RLR pathways and moderated the RNA metabolism, suggesting that it would be a potential lead compound for the development of anti-SARS-CoV-2 drugs.

12.
Artigo em Inglês | MEDLINE | ID: mdl-38381313

RESUMO

Sisomicin is a broad-spectrum aminoglycoside antibiotic and is the precursor of netilmicin and plazomicin. However, the fermentation level of sisomicin is still low compared with other antibiotics, which restricts the application of sisomicin and its derivatives. In this study, to improve sisomicin production, breeding of high-yielding sisomicin strains was conducted with chemical mutagenesis using Micromonospora inyoensis OG-1 (titer, 1042 U·mL-1) as the starting strain. Protoplast preparation was conducted under optimal conditions, and protoplast mutagenesis was performed with a suitable concentration of diethyl sulfate. Subsequently, a high-yielding and genetically stable strain (H6-32) was obtained by screening, with a sisomicin titer of 1486 U·mL-1 (an increase of 42.6%). Finally, carbon and nitrogen sources were optimized to further improve sisomicin production, and a sisomicin titer of 1780 U·mL-1 was ultimately obtained by controlling the dissolved oxygen level at 30% in a 5-L fermenter, which to the best of our knowledge is the highest reported titer ever achieved by fermentation. Comparative genome analysis showed that a total of 13 genes in the genome of the mutant strain H6-32 were mutated compared to the original strain. This study not only provides a reference for further breeding of high-yielding strains and fermentation optimization, but also enhances our understanding of sisomicin production.

13.
Cerebrovasc Dis ; 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38301613

RESUMO

BACKGROUND: This research explored the factors influencing early neurological outcomes (ENO) in patients who had vertebrobasilar artery occlusion (VBAO) and received endovascular treatment (EVT), as well as examining the causal influence of ENO on the prognosis of VBAO patients. METHODS: A retrospective review was carried out on patients from 65 Chinese stroke centers, all within 24 hours of the estimated occlusion time. ENO includes early neurological improvement (ENI) and early neurological deterioration (END), defined as a decrease or an increase of at least 4 points in NIHSS score between baseline and 24 hours after EVT. Death within 24 hours after EVT also consider as END. END was further divided into explainable END and unexplainable END (unEND). Independent predictors of ENO and the association between ENO and outcomes in patients with VBAO were determined using center-adjusted analyses. The study developed a multivariate logistic regression model to examine the comparative risk of unEND versus explainable END on the clinical outcomes in VBAO patients. RESULTS: A total of 2257 patients were included. Glasgow Coma Scale (GCS) (OR 1.16, 95% CI 1.03-1.30) and successful reperfusion (OR 1.15, 95% CI 1.02-1.30) were associated with ENI. Baseline NIHSS (OR 0.60, 95% CI 0.53-0.68), successful reperfusion (OR 0.79, 95% CI 0.71-0.89) and puncture to reperfusion time (OR 1.17, 95% CI 1.03-1.33) were associated with END. When examining three-month prognostic indexes, both END and ENI were found to be linked to the three-month outcomes, but in opposite directions. A subgroup analysis of END suggested that unexplained END typically demonstrated a more favorable prognosis compared to explained END, although the prognosis remained generally unfavorable. CONCLUSIONS: ENO, whether they manifested as early improvement or deterioration, were linked to the prognosis of VBAO patients undergoing EVT. The outcomes after unEND were more favorable than those following explained END.

14.
Curr Top Med Chem ; 24(3): 243-258, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38231069

RESUMO

The Hedgehog (Hh) signaling pathway plays a crucial role in diverse biological processes such as cell differentiation, proliferation, senescence, tumorigenesis, malignant transformation, and drug resistance. Aberrant Hh signaling, resulting from mutations and excessive activation, can contribute to the development of various diseases during different stages of biogenesis and development. Moreover, it has been linked to unfavorable outcomes in several human cancers, including basal cell carcinoma (BCC), multiple myeloma (MM), melanoma, and breast cancer. Hence, the presence of mutations and excessive activation of the Hh pathway presents obstacles and constraints in the realm of cancer treatment. Extant research has demonstrated that small molecule inhibitors are regarded as the most effective therapeutic approaches for targeting the Hh pathway in contrast to traditional chemotherapy and radiotherapy. Consequently, this review focuses on the present repertoire of small molecule inhibitors that target various components of the Hh pathway, including Hh ligands, Ptch receptors, Smo transmembrane proteins, and Gli nuclear transcription factors. This study provides a comprehensive analysis of small molecules' structural and functional aspects in the preclinical and clinical management of cancer. Additionally, it elucidates the obstacles encountered in targeting the Hh pathway for human cancer therapy and proposes potential therapeutic approaches.


Assuntos
Antineoplásicos , Proteínas Hedgehog , Neoplasias , Transdução de Sinais , Humanos , Proteínas Hedgehog/antagonistas & inibidores , Proteínas Hedgehog/metabolismo , Transdução de Sinais/efeitos dos fármacos , Antineoplásicos/farmacologia , Antineoplásicos/química , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/química , Animais
15.
J Am Chem Soc ; 146(2): 1209-1223, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38170467

RESUMO

Owing to its diverse activation processes including single-electron transfer (SET) and hydrogen-atom transfer (HAT), visible-light photocatalysis has emerged as a sustainable and efficient platform for organic synthesis. These processes provide a powerful avenue for the direct functionalization of C(sp3)-H bonds under mild conditions. Over the past decade, there have been remarkable advances in the enantioselective functionalization of the C(sp3)-H bond via photocatalysis combined with conventional asymmetric catalysis. Herein, we summarize the advances in asymmetric C(sp3)-H functionalization involving visible-light photocatalysis and discuss two main pathways in this emerging field: (a) SET-driven carbocation intermediates are followed by stereospecific nucleophile attacks; and (b) photodriven alkyl radical intermediates are further enantioselectively captured by (i) chiral π-SOMOphile reagents, (ii) stereoselective transition-metal complexes, and (iii) another distinct stereoscopic radical species. We aim to summarize key advances in reaction design, catalyst development, and mechanistic understanding, to provide new insights into this rapidly evolving area of research.

16.
Crit Rev Biotechnol ; 44(3): 448-461, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-36944486

RESUMO

L-serine and its derivative L-cysteine have broad industrial applications, and their direct fermentative production from renewable biomass is gaining increasing attention. Corynebacterium glutamicum is an extensively studied and well-established industrial microorganism, which is a predominant microbial host for producing amino acids. In this review, updated information on the genetics and molecular mechanisms underlying L-serine and L-cysteine production using C. glutamicum is presented, including their synthesis and degradation pathways, and other intracellular processes related to their production, as well as the mechanisms underlying substrate import and product export are also analyzed. Furthermore, metabolic strategies for strain improvement are systematically discussed, and conclusions and future perspectives for bio-based L-serine and L-cysteine production using C. glutamicum are presented. This review can provide a thorough understanding of L-serine and L-cysteine metabolic pathways to facilitate metabolic engineering modifications of C. glutamicum and development of more efficient industrial fermentation processes for L-serine and L-cysteine production.


Assuntos
Corynebacterium glutamicum , Cisteína , Cisteína/metabolismo , Serina/metabolismo , Corynebacterium glutamicum/genética , Aminoácidos/metabolismo , Engenharia Metabólica , Fermentação
17.
Adv Mater ; 36(5): e2305791, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37869962

RESUMO

Heat management is crucial for state-of-the-art applications such as passive radiative cooling, thermally adjustable wearables, and camouflage systems. Their adaptive versions, to cater to varied requirements, lean on the potential of adaptive metamaterials. Existing efforts, however, feature with highly anisotropic parameters, narrow working-temperature ranges, and the need for manual intervention, which remain long-term and tricky obstacles for the most advanced self-adaptive metamaterials. To surmount these barriers, heat-enhanced thermal diffusion metamaterials powered by deep learning is introduced. Such active metamaterials can automatically sense ambient temperatures and swiftly, as well as continuously, adjust their thermal functions with a high degree of tunability. They maintain robust thermal performance even when external thermal fields change direction, and both simulations and experiments demonstrate exceptional results. Furthermore, two metadevices with on-demand adaptability, performing distinctive features with isotropic materials, wide working temperatures, and spontaneous response are designed. This work offers a framework for the design of intelligent thermal diffusion metamaterials and can be expanded to other diffusion fields, adapting to increasingly complex and dynamic environments.

18.
Biotechnol J ; 19(1): e2300136, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37971189

RESUMO

The L-serine exporters ThrE and SerE play important roles in L-serine production by Corynebacterium glutamicum. Deletion of both thrE and serE decreased L-serine titer by 60%, suggesting the existence of other L-serine exporters. A comparative transcriptomics identified NCgl0254 and NCgl0255 as novel L-serine exporters. Further analysis of the contributions of ThrE, SerE, NCgl0254, and NCgl0255 found that SerE was the major L-serine exporter in C. glutamicum and these four L-serine exporters were responsible for 79.7% of L-serine export. Deletion of one L-serine exporter upregulated the transcription levels of the other three, which might be coursed by increased intracellular concentrations of L-serine. Overexpression of NCgl0254 and NCgl0255 increased L-serine titer by 20.8% in C. glutamicum A36, while overexpression of the four L-serine exporters increased L-serine production by 31.9% (41.1 g·L-1 ) in C. glutamicum A36. The identification of novel L-serine exporters in C. glutamicum will help to improve industrial production of L-serine.


Assuntos
Corynebacterium glutamicum , Corynebacterium glutamicum/genética , Serina , Proteínas de Bactérias/genética , Engenharia Metabólica
19.
Inflamm Res ; 73(3): 345-362, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38157008

RESUMO

OBJECTIVES: Colitis is a global disease usually accompanied by intestinal epithelial damage and intestinal inflammation, and an increasing number of studies have found natural products to be highly effective in treating colitis. Anemoside B4 (AB4), an abundant saponin isolated from Pulsatilla chinensis (Bunge), which was found to have strong anti-inflammatory activity. However, the exact molecular mechanisms and direct targets of AB4 in the treatment of colitis remain to be discovered. METHODS: The anti-inflammatory activities of AB4 were verified in LPS-induced cell models and 2, 4, 6-trinitrobenzene sulfonic (TNBS) or dextran sulfate sodium (DSS)-induced colitis mice and rat models. The molecular target of AB4 was identified by affinity chromatography analysis using chemical probes derived from AB4. Experiments including proteomics, molecular docking, biotin pull-down, surface plasmon resonance (SPR), and cellular thermal shift assay (CETSA) were used to confirm the binding of AB4 to its molecular target. Overexpression of pyruvate carboxylase (PC) and PC agonist were used to study the effects of PC on the anti-inflammatory and metabolic regulation of AB4 in vitro and in vivo. RESULTS: AB4 not only significantly inhibited LPS-induced NF-κB activation and increased ROS levels in THP-1 cells, but also suppressed TNBS/DSS-induced colonic inflammation in mice and rats. The molecular target of AB4 was identified as PC, a key enzyme related to fatty acid, amino acid and tricarboxylic acid (TCA) cycle. We next demonstrated that AB4 specifically bound to the His879 site of PC and altered the protein's spatial conformation, thereby affecting the enzymatic activity of PC. LPS activated NF-κB pathway and increased PC activity, which caused metabolic reprogramming, while AB4 reversed this phenomenon by inhibiting the PC activity. In vivo studies showed that diisopropylamine dichloroacetate (DADA), a PC agonist, eliminated the therapeutic effects of AB4 by changing the metabolic rearrangement of intestinal tissues in colitis mice. CONCLUSION: We identified PC as a direct cellular target of AB4 in the modulation of inflammation, especially colitis. Moreover, PC/pyruvate metabolism/NF-κB is crucial for LPS-driven inflammation and oxidative stress. These findings shed more light on the possibilities of PC as a potential new target for treating colitis.


Assuntos
Colite , Saponinas , Ratos , Camundongos , Animais , Piruvato Carboxilase/metabolismo , NF-kappa B/metabolismo , Lipopolissacarídeos/farmacologia , Simulação de Acoplamento Molecular , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colite/metabolismo , Inflamação/metabolismo , Saponinas/farmacologia , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Macrófagos/metabolismo , Sulfato de Dextrana/efeitos adversos , Sulfato de Dextrana/metabolismo , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças
20.
Metab Eng ; 81: 238-248, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38160746

RESUMO

Previously, a novel Corynebacterium glutamicum strain for the de novo biosynthesis of tailored poly-γ-glutamic acid (γ-PGA) has been constructed by our group. The strain was based on the γ-PGA synthetase complex, PgsBCA, which is the only polyprotein complex responsible for γ-PGA synthesis in Bacillus spp. In the present study, PgsBCA was reconstituted and overexpressed in C. glutamicum to further enhance γ-PGA synthesis. First, we confirmed that all the components (PgsB, PgsC, and PgsA) of γ-PGA synthetase derived from B. licheniformis are necessary for γ-PGA synthesis, and γ-PGA was detected only when PgsB, PgsC, and PgsA were expressed in combination in C. glutamicum. Next, the expression level of each pgsB, pgsC, and pgsA was tuned in order to explore the effect of expression of each of the γ-PGA synthetase subunits on γ-PGA production. Results showed that increasing the transcription levels of pgsB or pgsC and maintaining a medium-level transcription level of pgsA led to 35.44% and 76.53% increase in γ-PGA yield (γ-PGA yield-to-biomass), respectively. Notably, the expression level of pgsC had the greatest influence (accounting for 68.24%) on γ-PGA synthesis, followed by pgsB. Next, genes encoding for PgsC from four different sources (Bacillus subtilis, Bacillus anthracis, Bacillus methylotrophicus, and Bacillus amyloliquefaciens) were tested in order to identify the influence of PgsC-encoding orthologues on γ-PGA production, but results showed that in all cases the synthesis of γ-PGA was significantly inhibited. Similarly, we also explored the influence of gene orthologues encoding for PgsB on γ-PGA production, and found that the titer increased to 17.14 ± 0.62 g/L from 8.24 ± 0.10 g/L when PgsB derived from B. methylotrophicus replaced PgsB alone in PgsBCA from B. licheniformis. The resulting strain was chosen for further optimization, and we achieved a γ-PGA titer of 38.26 g/L in a 5 L fermentor by optimizing dissolved oxygen level. Subsequently, by supplementing glucose, γ-PGA titer increased to 50.2 g/L at 48 h. To the best of our knowledge, this study achieved the highest titer for de novo production of γ-PGA from glucose, without addition of L-glutamic acid, resulting in a novel strategy for enhancing γ-PGA production.


Assuntos
Corynebacterium glutamicum , Fermentação , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/metabolismo , Ácido Glutâmico , Ácido Poliglutâmico/genética , Ligases/metabolismo , Glucose/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...