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1.
Cell Rep ; 43(7): 114459, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38985674

RESUMEN

Glycine- and arginine-rich (GAR) motifs, commonly found in RNA-binding and -processing proteins, can be symmetrically (SDMA) or asymmetrically (ADMA) dimethylated at the arginine residue by protein arginine methyltransferases. Arginine-methylated protein motifs are usually read by Tudor domain-containing proteins. Here, using a GFP-Trap, we identify a non-Tudor domain protein, squamous cell carcinoma antigen recognized by T cells 3 (SART3), as a reader for SDMA-marked GAR motifs. Structural analysis and mutagenesis of SART3 show that aromatic residues lining a groove between two adjacent aromatic-rich half-a-tetratricopeptide (HAT) repeat domains are essential for SART3 to recognize and bind to SDMA-marked GAR motif peptides, as well as for the interaction between SART3 and the GAR-motif-containing proteins fibrillarin and coilin. Further, we show that the loss of this reader ability affects RNA splicing. Overall, our findings broaden the range of potential SDMA readers to include HAT domains.

2.
Cell Mol Life Sci ; 81(1): 283, 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38963422

RESUMEN

Protein SUMOylation is a prevalent stress-response posttranslational modification crucial for maintaining cellular homeostasis. Herein, we report that protein SUMOylation modulates cellular signaling mediated by cAMP, an ancient and universal stress-response second messenger. We identify K561 as a primary SUMOylation site in exchange protein directly activated by cAMP (EPAC1) via site-specific mapping of SUMOylation using mass spectrometry. Sequence and site-directed mutagenesis analyses reveal that a functional SUMO-interacting motif in EPAC1 is required for the binding of SUMO-conjugating enzyme UBC9, formation of EPAC1 nuclear condensate, and EPAC1 cellular SUMOylation. Heat shock-induced SUMO modification of EPAC1 promotes Rap1/2 activation in a cAMP-independent manner. Structural modeling and molecular dynamics simulation studies demonstrate that SUMO substituent on K561 of EPAC1 promotes Rap1 interaction by increasing the buried surface area between the SUMOylated receptor and its effector. Our studies identify a functional SUMOylation site in EPAC1 and unveil a novel mechanism in which SUMOylation of EPAC1 leads to its autonomous activation. The findings of SUMOylation-mediated activation of EPAC1 not only provide new insights into our understanding of cellular regulation of EPAC1 but also will open up a new field of experimentation concerning the cross-talk between cAMP/EPAC1 signaling and protein SUMOylation, two major cellular stress response pathways, during cellular homeostasis.


Asunto(s)
AMP Cíclico , Factores de Intercambio de Guanina Nucleótido , Sumoilación , Enzimas Ubiquitina-Conjugadoras , Proteínas de Unión al GTP rap1 , Factores de Intercambio de Guanina Nucleótido/metabolismo , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/química , Humanos , AMP Cíclico/metabolismo , Enzimas Ubiquitina-Conjugadoras/metabolismo , Enzimas Ubiquitina-Conjugadoras/genética , Proteínas de Unión al GTP rap1/metabolismo , Proteínas de Unión al GTP rap1/genética , Células HEK293 , Simulación de Dinámica Molecular , Complejo Shelterina/metabolismo , Transducción de Señal , Proteínas de Unión a Telómeros/metabolismo , Proteínas de Unión al GTP rap/metabolismo , Proteínas de Unión al GTP rap/genética , Respuesta al Choque Térmico , Secuencia de Aminoácidos , Unión Proteica
3.
J Zhejiang Univ Sci B ; 25(7): 581-593, 2024 Jul 15.
Artículo en Inglés, Chino | MEDLINE | ID: mdl-39011678

RESUMEN

Long non-coding RNAs (lncRNAs) play an indispensable role in the occurrence and development of ovarian cancer (OC). However, the potential involvement of lncRNAs in the progression of OC is largely unknown. To investigate the detailed roles and mechanisms ofRAD51 homolog B-antisense 1 (RAD51B-AS1), a novel lncRNA in OC, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to verify the expression of RAD51B-AS1. Cellular proliferation, metastasis, and apoptosis were detected using the cell counting kit-8 (CCK-8), colony-formation, transwell, and flow cytometry assays. Mouse xenograft models were established for the detection of tumorigenesis. The results revealed that RAD51B-AS1 was significantly upregulated in a highly metastatic human OC cell line and OC tissues. RAD51B-AS1 significantly increased the proliferation and metastasis of OC cells and enhanced their resistance to anoikis. Biogenetics prediction analysis revealed that the only target gene of RAD51B-AS1 was RAD51B. Subsequent gene function experiments revealed that RAD51B exerts the same biological effects as RAD51B-AS1. Rescue experiments demonstrated that the malignant biological behaviors promoted by RAD51B-AS1 overexpression were partially or completely reversed by RAD51B silencing in vitro and in vivo. Thus, RAD51B-AS1 promotes the malignant biological behaviors of OC and activates the protein kinase B (Akt)/B cell lymphoma protein-2 (Bcl-2) signaling pathway, and these effects may be associated with the positive regulation of RAD51B expression. RAD51B-AS1 is expected to serve as a novel molecular biomarker for the diagnosis and prediction of poor prognosis in OC, and as a potential therapeutic target for disease management.


Asunto(s)
Proliferación Celular , Proteínas de Unión al ADN , Regulación Neoplásica de la Expresión Génica , Neoplasias Ováricas , ARN Largo no Codificante , Regulación hacia Arriba , Femenino , Humanos , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Neoplasias Ováricas/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Ratones , Animales , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Apoptosis , Ratones Desnudos , Ratones Endogámicos BALB C , Proteínas Proto-Oncogénicas c-akt/metabolismo
4.
Front Bioeng Biotechnol ; 12: 1393154, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38938983

RESUMEN

Purpose: Conventional cephalomedullary nails (CMNs) are commonly employed for internal fixation in the treatment of reverse obliquity intertrochanteric (ROI) fractures. However, the limited effectiveness of conventional CMNs in addressing ROI fractures results in significant implant-related complications. To address challenges associated with internal fixation, a novel Proximal Femoral Bionic Nail (PFBN) has been developed. Methods: In this study, a finite element model was constructed using a normal femoral specimen, and biomechanical verification was conducted using the GOM non-contact optical strain measurement system. Four intramedullary fixation approaches-PFBN, Proximal Femoral Nail Antirotation InterTan nail (ITN), and Gamma nail (Gamma nail)-were employed to address three variations of ROI fractures (AO/OTA 31-A3). The biomechanical stability of the implant models was evaluated through the calculation of the von Mises stress contact pressure and displacement. Results: Compared to conventional CMNs, the PFBN group demonstrated a 9.36%-59.32% reduction in the maximum VMS at the implant. The A3.3 ROI fracture (75% bone density) was the most unstable type of fracture. In comparison to conventional CMNs, PFBN demonstrated more stable data, including VMS values (implant: 506.33 MPa, proximal fracture fragment: 34.41 MPa), contact pressure (13.28 MPa), and displacement (17.59 mm). Conclusion: Compared to the PFNA, ITN, and GN, the PFBN exhibits improvements in stress concentration, stress conduction, and overall model stability in ROI fractures. The double triangle structure aligns better with the tissue structure and biomechanical properties of the proximal femur. Consequently, the PFBN has significant potential as a new fixation strategy for the clinical treatment of ROI fractures.

5.
Epigenomes ; 8(2)2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38920624

RESUMEN

The post-genomic era has ushered in the extensive application of epigenetic editing tools, allowing for precise alterations of gene expression. The use of reprogrammable editors that carry transcriptional corepressors has significant potential for long-term epigenetic silencing for the treatment of human diseases. The ideal scenario involves precise targeting of a specific genomic location by a DNA-binding domain, ensuring there are no off-target effects and that the process yields no genetic remnants aside from specific epigenetic modifications (i.e., DNA methylation). A notable example is a recent study on the mouse Pcsk9 gene, crucial for cholesterol regulation and expressed in hepatocytes, which identified synthetic zinc-finger (ZF) proteins as the most effective DNA-binding editors for silencing Pcsk9 efficiently, specifically, and persistently. This discussion focuses on enhancing the specificity of ZF-array DNA binding by optimizing interactions between specific amino acids and DNA bases across three promoters containing CpG islands.

6.
Curr Opin Struct Biol ; 87: 102836, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38754172

RESUMEN

C2H2 zinc-finger (ZF) proteins form the largest family of DNA-binding transcription factors coded by mammalian genomes. In a typical DNA-binding ZF module, there are twelve residues (numbered from -1 to -12) between the last zinc-coordinating cysteine and the first zinc-coordinating histidine. The established C2H2-ZF "recognition code" suggests that residues at positions -1, -4, and -7 recognize the 5', central, and 3' bases of a DNA base-pair triplet, respectively. Structural studies have highlighted that additional residues at positions -5 and -8 also play roles in specific DNA recognition. The presence of bulky and either charged or polar residues at these five positions determines specificity for given DNA bases: guanine is recognized by arginine, lysine, or histidine; adenine by asparagine or glutamine; thymine or 5-methylcytosine by glutamate; and unmodified cytosine by aspartate. This review discusses recent structural characterizations of C2H2-ZFs that add to our understanding of the principles underlying the C2H2-ZF recognition code.

7.
Phys Med Biol ; 69(12)2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38729170

RESUMEN

Objective. Ovarian cancer is the deadliest gynecologic malignancy worldwide. Ultrasound is the most useful non-invasive test for preoperative diagnosis of ovarian cancer. In this study, by leveraging multiple ultrasound images from the same patient to generate personalized, informative statistical radiomic features, we aimed to develop improved ultrasound image-based prognostic models for ovarian cancer.Approach. A total of 2057 ultrasound images from 514 ovarian cancer patients, including 355 patients with epithelial ovarian cancer, from two hospitals in China were collected for this study. The models were constructed using our recently developed Frequency Appearance in Multiple Univariate pre-Screening feature selection algorithm and Cox proportional hazards model.Main results. The models showed high predictive performance for overall survival (OS) and recurrence-free survival (RFS) in both epithelial and nonepithelial ovarian cancer, with concordance indices ranging from 0.773 to 0.794. Radiomic scores predicted 2 year OS and RFS risk groups with significant survival differences (log-rank test,P< 1.0 × 10-4for both validation cohorts). OS and RFS hazard ratios between low- and high-risk groups were 15.994 and 30.692 (internal cohort) and 19.339 and 19.760 (external cohort), respectively. The improved performance of these newly developed prognostic models was mainly attributed to the use of multiple preoperative ultrasound images from the same patient to generate statistical radiomic features, rather than simply using the largest tumor region of interest among them. The models also revealed that the roundness of tumor lesion shape was positively correlated with prognosis for ovarian cancer.Significance.The newly developed prognostic models based on statistical radiomic features from ultrasound images were highly predictive of the risk of cancer-related death and possible recurrence not only for patients with epithelial ovarian cancer but also for those with nonepithelial ovarian cancer. They thereby provide reliable, non-invasive markers for individualized prognosis evaluation and clinical decision-making for patients with ovarian cancer.


Asunto(s)
Neoplasias Ováricas , Ultrasonografía , Humanos , Femenino , Neoplasias Ováricas/diagnóstico por imagen , Neoplasias Ováricas/mortalidad , Pronóstico , Persona de Mediana Edad , Procesamiento de Imagen Asistido por Computador/métodos , Adulto , Anciano , Radiómica
8.
bioRxiv ; 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38617249

RESUMEN

DNA methylation, as exemplified by cytosine-C5 methylation in mammals and adenine-N6 methylation in bacteria, is a crucial epigenetic mechanism driving numerous vital biological processes. Developing non-nucleoside inhibitors to cause DNA hypomethylation is a high priority, in order to treat a variety of significant medical conditions without the toxicities associated with existing cytidine-based hypomethylating agents. In this study, we have characterized fifteen quinoline-based analogs. Notably, compounds with additions like a methylamine ( 9 ) or methylpiperazine ( 11 ) demonstrate similar low micromolar inhibitory potency against both human DNMT1 (which generates C5-methylcytosine) and Clostridioides difficile CamA (which generates N6-methyladenine). Structurally, compounds 9 and 11 specifically intercalate into CamA-bound DNA via the minor groove, adjacent to the target adenine, leading to a substantial conformational shift that moves the catalytic domain away from the DNA. This study adds to the limited examples of DNA methyltransferases being inhibited by non-nucleotide compounds through DNA intercalation, following the discovery of dicyanopyridine-based inhibitors for DNMT1. Furthermore, our study shows that some of these quinoline-based analogs inhibit other enzymes that act on DNA, such as polymerases and base excision repair glycosylases. Finally, in cancer cells compound 11 elicits DNA damage response via p53 activation. Highlights: Six of fifteen quinoline-based derivatives demonstrated comparable low micromolar inhibitory effects on human cytosine methyltransferase DNMT1, and the bacterial adenine methyltransferases Clostridioides difficile CamA and Caulobacter crescentus CcrM. Compounds 9 and 11 were found to intercalate into a DNA substrate bound by CamA. These quinoline-based derivatives also showed inhibitory activity against various base excision repair DNA glycosylases, and DNA and RNA polymerases. Compound 11 provokes DNA damage response via p53 activation in cancer cells.

9.
Front Endocrinol (Lausanne) ; 15: 1372413, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38529390

RESUMEN

Introduction: Ovarian cancer (OV) is a highly lethal gynecological malignancy with a poor prognosis. Lactate metabolism is crucial for tumor cell survival, proliferation, and immune evasion. Our study aims to investigate the role of lactate metabolism-related genes (LMRGs) in OV and their potential as biomarkers for prognosis, immune microenvironment, and immunotherapy response. Methods: Ovarian samples were collected from the TCGA cohort. And 12 lactate-related pathways were identified from the MsigDB database. Differentially expressed genes within these pathways were designated as LMRGs, which undergo unsupervised clustering to identify distinct clusters based on LMRGs. Subsequently, we assessed survival outcomes, immune cell infiltration levels, Hallmaker pathway activation patterns, and chemotaxis among different subtypes. After conducting additional unsupervised clustering based on differentially expressed genes (DEGs), significant differences in the expression of LMRGs between the two clusters were observed. The differentially expressed genes were subjected to subsequent functional enrichment analysis. Furthermore, we construct a model incorporating LMRGs. Subsequently, the lactate score for each tumor sample was calculated based on this model, facilitating the classification of samples into high and low groups according to their respective lactate scores. Distinct groups examined disparities in survival prognosis, copy number variation (CNV), single nucleotide variation (SNV), and immune infiltration. The lactate score served as a quantitative measure of OV's lactate metabolism pattern and an independent prognostic factor. Results: This study investigated the potential role of LMRGs in tumor microenvironment diversity and prognosis in OV, suggesting that LMRGs play a crucial role in OV progression and the tumor microenvironment, thus serving as novel indicators for prognosis, immune microenvironment status, and response to immunotherapy.


Asunto(s)
Variaciones en el Número de Copia de ADN , Neoplasias Ováricas , Humanos , Femenino , Neoplasias Ováricas/genética , Pronóstico , Ácido Láctico , Microambiente Tumoral/genética
10.
Structure ; 32(3): 258-260, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38458157

RESUMEN

In this issue of Structure, Mahana et al.1 present their structural characterization of an annotated methyl-CpG-binding domain (MBD) from the histone H3 lysine 9 methyltransferase SETDB2. This study reveals that, rather than binding DNA as previously hypothesized, this domain instead interacts with a cystine-rich domain from C11orf46, highlighting its involvement in protein-protein interactions.


Asunto(s)
Metilación de ADN , Proteínas de Unión al ADN , Proteínas de Unión al ADN/química , ADN/metabolismo , Metiltransferasas/genética
11.
J Chromatogr A ; 1721: 464833, 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38555828

RESUMEN

A 3 µm undecylenic acid-functionalized stationary phase (UAS) was prepared for the separation of nucleosides and nucleobases using per aqueous liquid chromatography (PALC) and hydrophilic interaction liquid chromatography (HILIC). The retention behaviors of nucleosides and nucleobases in PALC and HILIC modes were explored by adjusting parameters such as water content, buffer concentration, pH of the mobile phase and column temperature. The experimental data and separation chromatogram demonstrated that PALC could provide retention comparable to that of HILIC for nucleosides and nucleobases. Comparative studies using diluted adenosine solutions evaluated theoretical plates and peak shape for the same retention factors (between 0.25 and 5.0) in PALC and HILIC. There was no buffer component in the mobile phases used to operate the comparisons. HILIC mode is more efficient for adenosine than PALC mode at low retention factors. It's the exact opposite phenomenon for high retention factors. It is proposed that the mass transfer of adenosine between the UAS, the water-rich layer and the ACN-rich mobile phase in HILIC is relatively slow. Given the significant use of toxic ACN in HILIC, PALC emerges as a safer and more effective alternative for separating nucleosides and nucleobases.


Asunto(s)
Nucleósidos , Dióxido de Silicio , Ácidos Undecilénicos , Dióxido de Silicio/química , Cromatografía Liquida/métodos , Interacciones Hidrofóbicas e Hidrofílicas , Agua/química , Indicadores y Reactivos , Adenosina
12.
Nano Lett ; 24(10): 3082-3088, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38416583

RESUMEN

The translational and rotational dynamics of anisotropic optical nanoprobes revealed in single particle tracking (SPT) experiments offer molecular-level information about cellular activities. Here, we report an automated high-speed multidimensional SPT system integrated with a deep learning algorithm for tracking the 3D orientation of anisotropic gold nanoparticle probes in living cells with high localization precision (<10 nm) and temporal resolution (0.9 ms), overcoming the limitations of rotational tracking under low signal-to-noise ratio (S/N) conditions. This method can resolve the azimuth (0°-360°) and polar angles (0°-90°) with errors of less than 2° on the experimental and simulated data under S/N of ∼4. Even when the S/N approaches the limit of 1, this method still maintains better robustness and noise resistance than the conventional pattern matching methods. The usefulness of this multidimensional SPT system has been demonstrated with a study of the motions of cargos transported along the microtubules within living cells.


Asunto(s)
Aprendizaje Profundo , Nanopartículas del Metal , Imagen Individual de Molécula , Oro , Transporte Biológico
13.
bioRxiv ; 2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38370764

RESUMEN

Although only a fraction of CTCF motifs are bound in any cell type, and approximately half of the occupied sites overlap cohesin, the mechanisms underlying cell-type specific attachment and ability to function as a chromatin organizer remain unknown. To investigate the relationship between CTCF and chromatin we applied a combination of imaging, structural and molecular approaches, using a series of brain and cancer associated CTCF mutations that act as CTCF perturbations. We demonstrate that binding and the functional impact of WT and mutant CTCF depend not only on the unique properties of each protein, but also on the genomic context of bound sites. Our studies also highlight the reciprocal relationship between CTCF and chromatin, demonstrating that the unique binding properties of WT and mutant proteins have a distinct impact on accessibility, TF binding, cohesin overlap, chromatin interactivity and gene expression programs, providing insight into their cancer and brain related effects.

14.
Future Oncol ; 20(4): 215-228, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38390682

RESUMEN

Recently, there has been an increased focus on cancer stem cells (CSCs) due to their resilience, making them difficult to eradicate. This resilience often leads to tumor recurrence and metastasis. CSCs adeptly manipulate their surroundings to create an environment conducive to their survival. In this environment, myeloid-derived suppressor cells (MDSCs) play a crucial role in promoting epithelial-mesenchymal transition and bolstering CSCs' stemness. In response, CSCs attract MDSCs, enhancing their infiltration, expansion and immunosuppressive capabilities. This interaction between CSCs and MDSCs increases the difficulty of antitumor therapy. In this paper, we discuss the interplay between CSCs and MDSCs based on current research and highlight recent therapeutic strategies targeting either CSCs or MDSCs that show promise in achieving effective antitumor outcomes.


Cancer stem cells (CSCs) are a kind of tumor cell. These cells are hard to kill but contribute to tumor progression and metastasis. Myeloid-derived suppressor cells (MDSCs) exist in the tumor tissue and are unfriendly to the antitumor immune response. The interaction between CSCs and MDSCs has a protective effect on tumor progression. Therapeutic strategies targeting CSCs or MDSCs present potential to weaken the complex interaction between the two cell types. This review summarizes the current knowledge of CSCs­MDSCs interaction and offers fresh perspectives on the future development of antitumor therapies targeting CSCs or MDSCs.


Asunto(s)
Células Supresoras de Origen Mieloide , Humanos , Recurrencia Local de Neoplasia/patología , Células Madre Neoplásicas/patología , Microambiente Tumoral
15.
Front Bioeng Biotechnol ; 12: 1352882, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38322788

RESUMEN

Purpose: Controversy remains regarding the optimal treatment for stage III Osteonecrosis of the femoral head (ONFH). This study presents, for the first time, the precise treatment of stage III ONFH using the "substitute the beam for a pillar" technique and performs a comparative finite element analysis with other hip-preserving procedures. Methods: A formalin-preserved femur of male cadavers was selected to obtain the CT scan data of femur. The proximal femur model was reconstructed and assembled using Mimics 20.0, Geomagic, and UG-NX 12.0 software with four different implant types: simple core decompression, fibula implantation, porous tantalum rod implantation, and partial replacement prosthesis. The finite element simulations were conducted to simulate the normal walking gait, and the stress distribution and displacement data of the femur and the implant model were obtained. Results: The peak von Mises stress of the femoral head and proximal femur in the partial replacement of the femoral head (PRFH) group were 22.8 MPa and 37.4 MPa, respectively, which were 3.1%-38.6% and 12.8%-37.4% lower than those of the other three surgical methods. Conclusion: The PRFH group exhibits better mechanical performance, reducing stress and displacement in the ONFH area, thus maintaining femoral head stability. Among the four hip-preserving approaches, from a biomechanical perspective, PRFH offers a new option for treating ONFH.

16.
bioRxiv ; 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38260470

RESUMEN

Exchange protein directly activated by cAMP (EPAC1) mediates the intracellular functions of a critical stress-response second messenger, cAMP. Herein, we report that EPAC1 is a cellular substrate of protein SUMOylation, a prevalent stress-response posttranslational modification. Site-specific mapping of SUMOylation by mass spectrometer leads to identifying K561 as a primary SUMOylation site in EPAC1. Sequence and site-directed mutagenesis analyses reveal a functional SUMO-interacting motif required for cellular SUMOylation of EPAC1. SUMO modification of EPAC1 mediates its heat shock-induced Rap1/2 activation in a cAMP-independent manner. Structural modeling and molecular dynamics simulation studies demonstrate that SUMO substituent on K561 of EPAC1 promotes Rap1 interaction by increasing the buried surface area between the SUMOylated receptor and its effector. Our studies identify a functional SUMOylation site in EPAC1 and unveil a novel mechanism in which SUMOylation of EPAC1 leads to its autonomous activation. The findings of SUMOylation-mediated activation of EPAC1 not only provide new insights into our understanding of cellular regulation of EPAC1 but also will open up a new field of experimentation concerning the cross-talk between cAMP/EPAC1 signaling and protein SUMOylation, two major cellular stress response pathways, during cellular homeostasis.

17.
Cell Rep ; 43(1): 113637, 2024 01 23.
Artículo en Inglés | MEDLINE | ID: mdl-38175749

RESUMEN

TREX2, a 3'-5' exonuclease, is a part of the DNA damage tolerance (DDT) pathway that stabilizes replication forks (RFs) by ubiquitinating PCNA along with the ubiquitin E3 ligase RAD18 and other DDT factors. Mismatch repair (MMR) corrects DNA polymerase errors, including base mismatches and slippage. Here we demonstrate that TREX2 deletion reduces mutations in cells upon exposure to genotoxins, including those that cause base lesions and DNA polymerase slippage. Importantly, we show that TREX2 generates most of the spontaneous mutations in MMR-mutant cells derived from mice and people. TREX2-induced mutagenesis is dependent on the nuclease and DNA-binding attributes of TREX2. RAD18 deletion also reduces spontaneous mutations in MMR-mutant cells, albeit to a lesser degree. Inactivation of both MMR and TREX2 additively increases RF stalls, while it decreases DNA breaks, consistent with a synthetic phenotype.


Asunto(s)
ADN Polimerasa Dirigida por ADN , Mutágenos , Humanos , Ratones , Animales , Mutagénesis , ADN Polimerasa Dirigida por ADN/metabolismo , Mutación , Ubiquitina/metabolismo , Replicación del ADN , Exodesoxirribonucleasas/genética , Exodesoxirribonucleasas/metabolismo , Fosfoproteínas/genética , Proteínas de Unión al ADN/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo
18.
Biochem Genet ; 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38270698

RESUMEN

Increasing evidence has demonstrated that CXCRs are associated with the tumor infiltration of immune cells and regulate the tumor immune response. However, the prognostic value of CXCRs expression in patients with skin cutaneous melanoma (SKCM) remains unclear. In this study, we aimed to investigate the expression characteristics of CXCRs in SKCM tissues, analyze their prognostic value and the correlation with immune cell infiltration. Multiple public databases were used for exploration, including GEPIA2, GSCA, ULCAN, Metascape, STRING, TIMER2.0, HPA, and Cistrome DB database. And a confirmation experiment was conducted on melanoma mice with flow cytometry. Compared with normal tissues, lower expression of CXCR2/7/8 and higher expression of CXCR3/4 were found in SKCM tissues. CXCR3/4/6 were abnormally expressed in each pathological stage. Moreover, CXCRs were closely related to immune-related biological functions, and mainly interacted with CXCLs. The high expression of CXCR3/5/6 indicated better overall survival of patients. Among them, CXCR6 had the most significant prognostic value, and was most related to tumor infiltration of CD8+T cells, which was verified in melanoma mice. Finally, ETS1 and STAT5B were predicted as the transcription factor of CXCR6. Our findings play an important role in the study of prognostic markers in patients with SKCM.

19.
Spectrochim Acta A Mol Biomol Spectrosc ; 309: 123843, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38215563

RESUMEN

The chlorophyll content reflects plants' photosynthetic capacity, growth stage, and nitrogen status. Maize is one of the three widely planted gain crops in the world. In order to offer useful information for the development of chlorophyll content detectors of maize leaves, a single integrating sphere system was used to measure the transmittance and reflectance spectra of maize leaves over the wavelength range of 500-950 nm. The linear relationships of transmittance and reflectance with chlorophyll content were investigated. The feature wavelengths (FWs) sensitive to chlorophyll content were extracted from the full transmittance and reflectance spectra using the successive projections algorithm (SPA). The partial least squares regression (PLSR) models for predicting the chlorophyll content were established using the full spectra and extracted FWs. The results showed that there were obvious linear relationships between transmittance and reflectance with chlorophyll content of maize leaves and the best linear relationships were found at 709 nm and 714 nm, respectively, with the linear correlation coefficients of 0.801 and 0.696, and the root-mean-squares error (RMSEP) of 0.321 mg·g-1 and 0.405 mg·g-1, respectively. Eight and 6 FWs were extracted from the transmittance and reflectance spectra, respectively. The PLSR model established using the selected FWs from transmittance spectra had better prediction performance with RMSEP of 0.208 mg·g-1 than using full transmittance spectra. The built PLSR models using the full reflectance spectra and extracted FWs had poor robustness. This research offers some theoretical basis for developing a maize leaf chlorophyll content detector based on transmittance or reflectance.


Asunto(s)
Clorofila , Zea mays , Análisis de los Mínimos Cuadrados , Hojas de la Planta , Fotosíntesis , Plantas
20.
Int Immunopharmacol ; 126: 111303, 2024 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-38043269

RESUMEN

Endogenous neural stem cells (NSCs) have the potential to generate remyelinating oligodendrocytes, which play an important role in multiple sclerosis (MS). However, the differentiation of NSCs into oligodendrocytes is insufficient, which is considered a major cause of remyelination failure. Our previous work reported that Astragalus polysaccharides (APS) had a neuroprotective effect on experimental autoimmune encephalomyelitis (EAE) mice. However, it remains unclear whether APS regulate NSCs differentiation in EAE mice. In this study, our data illustrated that APS administration could promote NSCs in the subventricular zone (SVZ) to differentiate into oligodendrocytes. Furthermore, we found that APS significantly improved neuroinflammation and inhibited CD8+T cell infiltration into SVZ of EAE mice. We also found that MOG35-55-specific CD8+T cells suppressed NSCs differentiation into oligodendrocytes by secreting IFN-γ, and APS facilitated the differentiation of NSCs into oligodendrocytes which was related to decreased IFN-γ secretion. In addition, APS treatment did not show a better effect on the NSCs-derived oligodendrogenesis after CD8+T cell depletion. This present study demonstrated that APS alleviated neuroinflammation and CD8+T cell infiltration into SVZ to induce oligodendroglial differentiation, and thus exerted neuroprotective effect. Our findings revealed that reducing the infiltration of CD8+T cells might contribute to enhancing NSCs-derived neurogenesis. And APS might be a promising drug candidate to treat MS.


Asunto(s)
Encefalomielitis Autoinmune Experimental , Esclerosis Múltiple , Células-Madre Neurales , Fármacos Neuroprotectores , Ratones , Animales , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Enfermedades Neuroinflamatorias , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Esclerosis Múltiple/tratamiento farmacológico , Diferenciación Celular/fisiología , Polisacáridos/farmacología , Polisacáridos/uso terapéutico , Linfocitos T , Ratones Endogámicos C57BL
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