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1.
Nat Commun ; 15(1): 5761, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38982055

RESUMO

While protein aggregation's association with aging and age-related diseases is well-established, the specific proteins involved and whether dissolving them could alleviate aging remain unclear. Our research addresses this gap by uncovering the role of PKM2 aggregates in aging. We find that PKM2 forms aggregates in senescent cells and organs from aged mice, impairing its enzymatic activity and glycolytic flux, thereby driving cells into senescence. Through a rigorous two-step small molecule library screening, we identify two compounds, K35 and its analog K27, capable of dissolving PKM2 aggregates and alleviating senescence. Further experiments show that treatment with K35 and K27 not only alleviate aging-associated signatures but also extend the lifespan of naturally and prematurely aged mice. These findings provide compelling evidence for the involvement of PKM2 aggregates in inducing cellular senescence and aging phenotypes, and suggest that targeting these aggregates could be a promising strategy for anti-aging drug discovery.


Assuntos
Envelhecimento , Senescência Celular , Proteínas de Ligação a Hormônio da Tireoide , Animais , Envelhecimento/metabolismo , Camundongos , Humanos , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Proteínas de Transporte/metabolismo , Glicólise , Hormônios Tireóideos/metabolismo , Agregados Proteicos , Piruvato Quinase/metabolismo , Camundongos Endogâmicos C57BL , Masculino
2.
Biomater Sci ; 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39037353

RESUMO

Mesenchymal stem cells (MSCs) exhibit substantial potential for osteoarthritis (OA) therapy through cartilage regeneration, yet the realization of optimal therapeutic outcomes is hampered by their limited intrinsic reparative capacities. Herein, MSCs are engineered with circular mRNA (cmRNA) encoding fibroblast growth factor 18 (FGF18) encapsulated within lipid nanoparticles (LNP) derived from a glycerolipid to facilitate OA healing. A proprietary biodegradable and ionizable glycerolipid, TG6A, with branched tails and five ester bonds, forms LNP exhibiting above 9-fold and 41-fold higher EGFP protein expression in MSCs than commercial LNP from DLin-MC3-DMA and ALC-0315, respectively. The introduction of FGF18 not only augmented the proliferative capacity of MSCs but also upregulated the expression of chondrogenic genes and glycosaminoglycan (GAG) content. Additionally, FGF18 enhanced the production of proteoglycans and type II collagen in chondrocyte pellet cultures in a three-dimensional culture. In an OA rat model, transplantation with FGF18-engineered MSCs remarkably preserved cartilage integrity and facilitated functional repair of cartilage lesions, as evidenced by thicker cartilage layers, reduced histopathological scores, maintenance of zone structure, and incremental type II collagen and extracellular matrix (ECM) deposition. Taken together, our findings suggest that TG6A-based LNP loading with cmRNA for engineering MSCs present an innovative strategy to overcome the current limitations in OA treatment.

3.
Nat Commun ; 15(1): 5953, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39009586

RESUMO

The intracellular bacterial pathogen Legionella pneumophila modulates host cell functions by secreting multiple effectors with diverse biochemical activities. In particular, effectors of the SidE family interfere with host protein ubiquitination in a process that involves production of phosphoribosyl ubiquitin (PR-Ub). Here, we show that effector LnaB converts PR-Ub into ADP-ribosylated ubiquitin, which is further processed to ADP-ribose and functional ubiquitin by the (ADP-ribosyl)hydrolase MavL, thus maintaining ubiquitin homeostasis in infected cells. Upon being activated by actin, LnaB also undergoes self-AMPylation on tyrosine residues. The activity of LnaB requires a motif consisting of Ser, His and Glu (SHxxxE) present in a large family of toxins from diverse bacterial pathogens. Thus, our study sheds light on the mechanisms by which a pathogen maintains ubiquitin homeostasis and identifies a family of enzymes capable of protein AMPylation.


Assuntos
Proteínas de Bactérias , Homeostase , Legionella pneumophila , Ubiquitina , Ubiquitinação , Ubiquitina/metabolismo , Legionella pneumophila/metabolismo , Legionella pneumophila/patogenicidade , Humanos , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , ADP-Ribosilação , Interações Hospedeiro-Patógeno , Adenosina Difosfato Ribose/metabolismo , Doença dos Legionários/metabolismo , Doença dos Legionários/microbiologia , Células HEK293 , Actinas/metabolismo , Células HeLa
5.
Plant Physiol Biochem ; 213: 108841, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38879987

RESUMO

Epigenetic modifications, such as histone alterations, play crucial roles in regulating the flowering process in Arabidopsis, a typical long-day model plant. Histone modifications are notably involved in the intricate regulation of FLC, a key inhibitor of flowering. Although sirtuin-like protein and NAD+-dependent deacetylases play an important role in regulating energy metabolism, plant stress responses, and hormonal signal transduction, the mechanisms underlying their developmental transitions remain unclear. Thus, this study aimed to reveal how Arabidopsis NAD + -dependent deacetylase AtSRT1 affects flowering by regulating the expression of flowering integrators. Genetic and molecular evidence demonstrated that AtSRT1 mediates histone deacetylation by directly binding near the transcriptional start sites (TSS) of the flowering integrator genes FT and SOC1 and negatively regulating their expression by modulating the expression of the downstream gene LFY to inhibit flowering. Additionally, AtSRT1 directly down-regulates the expression of TOR, a glucose-driven central hub of energy signaling, which controls cell metabolism and growth in response to nutritional and environmental factors. This down-regulation occurs through binding near the TSS of TOR, facilitating the addition of H3K27me3 marks on FLC via the TOR-FIE-PRC2 pathway, further repressing flowering. These results uncover a multi-pathway regulatory network involving deacetylase AtSRT1 during the flowering process, highlighting its interaction with TOR as a hub for the coordinated regulation of energy metabolism and flowering initiation. These findings significantly enhance understanding of the complexity of histone modifications in the regulation of flowering.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Flores , Regulação da Expressão Gênica de Plantas , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Flores/genética , Flores/crescimento & desenvolvimento , Transdução de Sinais , Proteínas de Domínio MADS/metabolismo , Proteínas de Domínio MADS/genética , Histonas/metabolismo , Metabolismo Energético/genética , Histona Desacetilases/metabolismo , Histona Desacetilases/genética
6.
Cell Mol Life Sci ; 81(1): 249, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38836877

RESUMO

Protein ubiquitination is one of the most important posttranslational modifications (PTMs) in eukaryotes and is involved in the regulation of almost all cellular signaling pathways. The intracellular bacterial pathogen Legionella pneumophila translocates at least 26 effectors to hijack host ubiquitination signaling via distinct mechanisms. Among these effectors, SidC/SdcA are novel E3 ubiquitin ligases with the adoption of a Cys-His-Asp catalytic triad. SidC/SdcA are critical for the recruitment of endoplasmic reticulum (ER)-derived vesicles to the Legionella-containing vacuole (LCV). However, the ubiquitination targets of SidC/SdcA are largely unknown, which restricts our understanding of the mechanisms used by these effectors to hijack the vesicle trafficking pathway. Here, we demonstrated that multiple Rab small GTPases and target soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins are bona fide ubiquitination substrates of SidC/SdcA. SidC/SdcA-mediated ubiquitination of syntaxin 3 and syntaxin 4 promotes their unconventional pairing with the vesicle-SNARE protein Sec22b, thereby contributing to the membrane fusion of ER-derived vesicles with the phagosome. In addition, our data reveal that ubiquitination of Rab7 by SidC/SdcA is critical for its association with the LCV membrane. Rab7 ubiquitination could impair its binding with the downstream effector Rab-interacting lysosomal protein (RILP), which partially explains why LCVs avoid fusion with lysosomes despite the acquisition of Rab7. Taken together, our study reveals the biological mechanisms employed by SidC/SdcA to promote the maturation of the LCVs.


Assuntos
Legionella pneumophila , Fagossomos , Proteínas SNARE , Ubiquitinação , Proteínas rab de Ligação ao GTP , Legionella pneumophila/metabolismo , Humanos , Fagossomos/metabolismo , Fagossomos/microbiologia , Proteínas SNARE/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Animais , Proteínas Qa-SNARE/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Vacúolos/metabolismo , Vacúolos/microbiologia , Células HEK293 , Camundongos , proteínas de unión al GTP Rab7/metabolismo , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Retículo Endoplasmático/metabolismo
7.
J Hazard Mater ; 475: 134913, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38880048

RESUMO

Photoinitiators (PIs) are chemical additives that generate active substances, such as free radicals to initiate photopolymerization. Traditionally, polymerization has been considered a green technique that seldomly generates contaminants. However, many researches have confirmed toxicity effects of PIs, such as carcinogenicity, cytotoxicity, endocrine disrupting effects. Surprisingly, we found high levels of PIs in indoor dust. Our analysis revealed comparable levels of PIs in dust from printing shops (geometric mean, GM: 1.33 ×103 ng/g) and control environments (GM: 874 ng/g), underscoring the widespread presence of PIs across various settings. Alarmingly, in dust samples from nail salons, PIs were detected at total concentrations ranging from 610 to 1.04 × 107 ng/g (GM: 1.87 ×105 ng/g), significantly exceeding those in the control environments (GM: 1.43 ×103 ng/g). Nail salon workers' occupational exposure to PIs through dust ingestion was estimated at 4.86 ng/kg body weight/day. Additionally, an in vitro simulated digestion test suggested that between 10 % and 42 % of PIs present in ingested dust could become bioaccessible to humans. This is the first study to report on PIs in the specific environments of nail salons and printing shops. This study highlights the urgent need for public awareness regarding the potential health risks posed by PIs to occupational workers, marking an important step towards our understanding of environmental pollution caused by PIs.


Assuntos
Poeira , Exposição Ocupacional , Poeira/análise , Exposição Ocupacional/análise , Humanos , Medição de Risco , Poluição do Ar em Ambientes Fechados/análise , Indústria da Beleza , Poluentes Ocupacionais do Ar/análise , Poluentes Ocupacionais do Ar/toxicidade
8.
Nat Commun ; 15(1): 4740, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38834545

RESUMO

Mitophagy is critical for mitochondrial quality control and function to clear damaged mitochondria. Here, we found that Burkholderia pseudomallei maneuvered host mitophagy for its intracellular survival through the type III secretion system needle tip protein BipD. We identified BipD, interacting with BTB-containing proteins KLHL9 and KLHL13 by binding to the Back and Kelch domains, recruited NEDD8 family RING E3 ligase CUL3 in response to B. pseudomallei infection. Although evidently not involved in regulation of infectious diseases, KLHL9/KLHL13/CUL3 E3 ligase complex was essential for BipD-dependent ubiquitination of mitochondria in mouse macrophages. Mechanistically, we discovered the inner mitochondrial membrane IMMT via host ubiquitome profiling as a substrate of KLHL9/KLHL13/CUL3 complex. Notably, K63-linked ubiquitination of IMMT K211 was required for initiating host mitophagy, thereby reducing mitochondrial ROS production. Here, we show a unique mechanism used by bacterial pathogens that hijacks host mitophagy for their survival.


Assuntos
Proteínas de Bactérias , Burkholderia pseudomallei , Macrófagos , Mitocôndrias , Mitofagia , Burkholderia pseudomallei/metabolismo , Burkholderia pseudomallei/patogenicidade , Burkholderia pseudomallei/fisiologia , Burkholderia pseudomallei/genética , Animais , Camundongos , Mitocôndrias/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Humanos , Macrófagos/microbiologia , Macrófagos/metabolismo , Ubiquitinação , Melioidose/microbiologia , Melioidose/metabolismo , Interações Hospedeiro-Patógeno , Espécies Reativas de Oxigênio/metabolismo , Sistemas de Secreção Tipo III/metabolismo , Sistemas de Secreção Tipo III/genética , Camundongos Endogâmicos C57BL , Membranas Mitocondriais/metabolismo , Células HEK293 , Células RAW 264.7
9.
Res Sq ; 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38826349

RESUMO

The reversal of ubiquitination induced by members of the SidE effector family of Legionella pneumophila produces phosphoribosyl ubiquitin (PR-Ub) that is potentially detrimental to host cells. Here we show that the effector LnaB functions to transfer the AMP moiety from ATP to the phosphoryl moiety of PR-Ub to convert it into ADP-ribosylated ubiquitin (ADPR-Ub), which is further processed to ADP-ribose and functional ubiquitin by the (ADP-ribosyl)hydrolase MavL, thus maintaining ubiquitin homeostasis in infected cells. Upon being activated by Actin, LnaB also undergoes self-AMPylation on tyrosine residues. The activity of LnaB requires a motif consisting of Ser, His and Glu (S-HxxxE) present in a large family of toxins from diverse bacterial pathogens. Our study not only reveals intricate mechanisms for a pathogen to maintain ubiquitin homeostasis but also identifies a new family of enzymes capable of protein AMPylation, suggesting that this posttranslational modification is widely used in signaling during host-pathogen interactions.

10.
Hum Resour Health ; 22(1): 45, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38937757

RESUMO

BACKGROUND: Gender equality and the gender income gap in medicine are long-standing global problems. Although gender-related differences have been widely studied in developed countries, they remain unclear in underdeveloped regions. In 2010, China initiated a national compulsory service program (CSP) to train qualified general practitioners in rural and remote areas. This study aimed to evaluate gender income differences for early career CSP and non-CSP (NCSP) graduates in underdeveloped areas. METHODS: A cohort study was conducted with 3620 CSP and NCSP graduates from four medical universities in Central and Western China. Baseline surveys and six follow-up surveys were conducted between 2015 and 2022. Incomes, including monthly mean income and proportion of performance-based income, were measured as the key outcome variables. Multivariate linear regression models were used to identify the gender income gap. RESULTS: NCSP graduates had higher average monthly incomes than CSP graduates. In the seventh year after graduation, the average monthly income for NCSP graduates was 7859 CNY while was 5379 CNY for CSP graduates. After controlling for demographic characteristics, the gender monthly income gap for CSP graduates was expanded from the fourth year (3.0%) to the sixth year (5.9%) after graduation, and that for NCSP graduates was expanded from the fifth year (11.9%) to the seventh year (16.3%) after graduation. Regarding performance-based income, it was 58.9% for NCSP graduates and 45.8% for CSP graduates in the seventh year after graduation. After controlling for performance-based income proportion, the gender income gap was reduced from 5.9 to 4.0% in the sixth year after graduation for CSP graduates, and from 16.3 to 14.4% for NCSP graduates in the seventh year after graduation. CONCLUSION: An extensive and ever-increasing gender income gap exists among young doctors in the early stages of their careers in underdeveloped areas of China. The high proportion of performance-based income among men is one of the main explanations for the observed difference. A more explicit compensation system must be established to enhance support for female health workers.


Assuntos
Clínicos Gerais , Renda , Humanos , China , Masculino , Feminino , Estudos Prospectivos , Adulto , Fatores Sexuais , Serviços de Saúde Rural , População Rural , Sexismo/estatística & dados numéricos
11.
BMJ Open ; 14(5): e080844, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38821576

RESUMO

OBJECTIVES: The aim of this study was to assess the quality of tuberculosis (TB) care for the whole course and assess factors that affect completing treatment. DESIGN: This is an observational retrospective study using chart abstraction for the whole course of TB care conducted at two underserved provinces in China. SETTING: The study was conducted from June 2021 to July 2021. All medical records (outpatient and inpatient) for the whole course (6-8 months) of patients with TB newly registered from July 2020 to December 2020 were reviewed and abstracted using predetermined checklists. PARTICIPANTS: A total of 268 outpatient medical records and 126 inpatient records were included. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome included diagnostic quality, treatment quality and management quality. The secondary outcome was completing treatment. RESULTS: For diagnostic quality, 94.2% of the diagnosis were based on adequate evidence. For treatment quality, 240 (91.6%) outpatients and 100 (85.5%) inpatients took the standard chemotherapy regimens. 234 (87.3%) patients completed treatment. 85.1% of the inpatients prescribed with second-line drugs were inappropriate. For management quality, 128 (47.9%) patients received midterm assessments, but only 47 (19.7%) received sufficient services for the whole course. Patients with TB symptoms were 1.8 times more likely to complete treatment (p=0.011). CONCLUSION: Patients with TB received high-quality diagnosis and treatment services, but low-quality whole-course management. Integration of medical and public health services should be strengthened to improve whole-course quality.


Assuntos
Qualidade da Assistência à Saúde , Tuberculose , Humanos , Estudos Retrospectivos , China , Feminino , Masculino , Adulto , Pessoa de Meia-Idade , Tuberculose/terapia , Tuberculose/tratamento farmacológico , Tuberculose/diagnóstico , Antituberculosos/uso terapêutico , População Rural , Adulto Jovem , Idoso , Adolescente , Prontuários Médicos
12.
Nature ; 631(8020): 393-401, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38776962

RESUMO

AMPylation is a post-translational modification in which AMP is added to the amino acid side chains of proteins1,2. Here we show that, with ATP as the ligand and actin as the host activator, the effector protein LnaB of Legionella pneumophila exhibits AMPylase activity towards the phosphoryl group of phosphoribose on PRR42-Ub that is generated by the SidE family of effectors, and deubiquitinases DupA and DupB in an E1- and E2-independent ubiquitination process3-7. The product of LnaB is further hydrolysed by an ADP-ribosylhydrolase, MavL, to Ub, thereby preventing the accumulation of PRR42-Ub and ADPRR42-Ub and protecting canonical ubiquitination in host cells. LnaB represents a large family of AMPylases that adopt a common structural fold, distinct from those of the previously known AMPylases, and LnaB homologues are found in more than 20 species of bacterial pathogens. Moreover, LnaB also exhibits robust phosphoryl AMPylase activity towards phosphorylated residues and produces unique ADPylation modifications in proteins. During infection, LnaB AMPylates the conserved phosphorylated tyrosine residues in the activation loop of the Src family of kinases8,9, which dampens downstream phosphorylation signalling in the host. Structural studies reveal the actin-dependent activation and catalytic mechanisms of the LnaB family of AMPylases. This study identifies, to our knowledge, an unprecedented molecular regulation mechanism in bacterial pathogenesis and protein phosphorylation.


Assuntos
Monofosfato de Adenosina , Proteínas de Bactérias , Legionella pneumophila , Fosfotirosina , Transdução de Sinais , Humanos , Actinas/metabolismo , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , ADP-Ribosilação , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Hidrólise , Legionella pneumophila/enzimologia , Legionella pneumophila/metabolismo , Legionella pneumophila/patogenicidade , Ligantes , Modelos Moleculares , N-Glicosil Hidrolases/metabolismo , Fosforilação , Processamento de Proteína Pós-Traducional , Tirosina/metabolismo , Tirosina/química , Ubiquitina/metabolismo , Ubiquitinação , Enzimas Desubiquitinantes/metabolismo , Dobramento de Proteína , Fosfotirosina/química , Fosfotirosina/metabolismo
13.
Basic Clin Androl ; 34(1): 9, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38711076

RESUMO

BACKGROUND: Only a few cases have been reported about active foreign body implantation in the cavernous body of the penis. CASE PRESENTATION: A 47-year-old man inserted two needles from the glans penis into the bilateral penile sponge body. Subsequently, two needles migrated through the penile cavernous body into the pelvic cavity. Attempts to remove the needles through the penis were unsuccessful. Eventually, after a duration exceeding one month, the displaced needles were removed in stages from the buttocks. CONCLUSION: A few cases of intracavernosal-injection-therapy-associated needle breakage and retention have been reported globally. And this is the first case in China documenting the migration of foreign bodies within the penile region. In this condition, it is of utmost importance to engage the expertise of experienced andrologists to minimize the risk of excessive manipulation, thereby ensuring that inadvertent deep penetration of the needle into the penile tissue is prevented. In case the foreign body has migrated deeper into the tissues and the patient does not exhibit any specific symptoms or risks of macrovascular injury-related bleeding, close surveillance of its movement can be implemented. Surgical intervention can be initiated once the foreign body has reached a suitable position. Moreover, a psychiatric evaluation should be recommended for patient to discover any underlying mental health disorders.


RéSUMé: CONTEXTE: Seuls quelques cas ont été rapportés concernant l'implantation active d'un corps étranger dans le corps caverneux du pénis. PRéSENTATION DU CAS: Un homme de 47 ans a inséré deux aiguilles, par le gland du pénis, dans les corps spongieux du pénis. Par la suite, les deux aiguilles ont migré à travers le corps caverneux du pénis jusque dans la cavité pelvienne. Les tentatives pour retirer les aiguilles à travers le pénis ont été infructueuses. Finalement, après une durée de plus d'un mois, les aiguilles déplacées ont été retirées, par étapes, au niveau des fesses. CONCLUSION: Quelques cas de rupture et de rétention d'aiguille associés au traitement par injection intracaverneuse ont été signalés dans le monde. Il s'agit ici du premier cas en Chine qui documente la migration de corps étrangers dans la région du pénis. Dans cette situation, il est de la plus haute importance de faire appel à l'expertise d'andrologues expérimentés pour minimiser le risque de manipulation excessive, garantissant ainsi que la pénétration profonde par inadvertance de l'aiguille dans le tissu pénien est prévenue. Dans le cas où le corps étranger a migré plus profondément dans les tissus et que le patient ne présente pas de symptômes spécifiques ou de risques de saignements liés à une lésion macrovasculaire, une surveillance étroite du mouvement du corps étranger peut être mise en œuvre. L'intervention chirurgicale peut être initiée une fois que le corps étranger a atteint une position appropriée. Enfin, une évaluation psychiatrique devrait être recommandée à la recherche de tout trouble sous-jacent de santé mentale.

14.
J Cancer ; 15(10): 3152-3153, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38706919

RESUMO

[This corrects the article DOI: 10.7150/jca.53385.].

15.
Nat Commun ; 15(1): 3890, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38719850

RESUMO

Shigella flexneri is a Gram-negative bacterium causing severe bloody dysentery. Its pathogenesis is largely dictated by a plasmid-encoded type III secretion system (T3SS) and its associated effectors. Among these, the effector OspG has been shown to bind to the ubiquitin conjugation machinery (E2~Ub) to activate its kinase activity. However, the cellular targets of OspG remain elusive despite years of extensive efforts. Here we show by unbiased phosphoproteomics that a major target of OspG is CAND1, a regulatory protein controlling the assembly of cullin-RING ubiquitin ligases (CRLs). CAND1 phosphorylation weakens its interaction with cullins, which is expected to impact a large panel of CRL E3s. Indeed, global ubiquitome profiling reveals marked changes in the ubiquitination landscape when OspG is introduced. Notably, OspG promotes ubiquitination of a class of cytoskeletal proteins called septins, thereby inhibiting formation of cage-like structures encircling cytosolic bacteria. Overall, we demonstrate that pathogens have evolved an elaborate strategy to modulate host ubiquitin signaling to evade septin-cage entrapment.


Assuntos
Proteínas de Bactérias , Septinas , Shigella flexneri , Transdução de Sinais , Ubiquitina , Ubiquitinação , Shigella flexneri/metabolismo , Shigella flexneri/patogenicidade , Septinas/metabolismo , Septinas/genética , Humanos , Ubiquitina/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Fosforilação , Interações Hospedeiro-Patógeno , Células HeLa , Proteínas Culina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Células HEK293 , Disenteria Bacilar/microbiologia , Disenteria Bacilar/metabolismo
16.
Front Bioeng Biotechnol ; 12: 1374352, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38694621

RESUMO

Background: The treatment of patellar tendon injury has always been an unsolved problem, and mechanical characterization is very important for its repair and reconstruction. Elastin is a contributor to mechanics, but it is not clear how it affects the elasticity, viscoelastic properties, and structure of patellar tendon. Methods: The patellar tendons from six fresh adult experimental pigs were used in this study and they were made into 77 samples. The patellar tendon was specifically degraded by elastase, and the regional mechanical response and structural changes were investigated by: (1) Based on the previous study of elastase treatment conditions, the biochemical quantification of collagen, glycosaminoglycan and total protein was carried out; (2) The patellar tendon was divided into the proximal, central, and distal regions, and then the axial tensile test and stress relaxation test were performed before and after phosphate-buffered saline (PBS) or elastase treatment; (3) The dynamic constitutive model was established by the obtained mechanical data; (4) The structural relationship between elastin and collagen fibers was analyzed by two-photon microscopy and histology. Results: There was no statistical difference in mechanics between patellar tendon regions. Compared with those before elastase treatment, the low tensile modulus decreased by 75%-80%, the high tensile modulus decreased by 38%-47%, and the transition strain was prolonged after treatment. For viscoelastic behavior, the stress relaxation increased, the initial slope increased by 55%, the saturation slope increased by 44%, and the transition time increased by 25% after enzyme treatment. Elastin degradation made the collagen fibers of patellar tendon become disordered and looser, and the fiber wavelength increased significantly. Conclusion: The results of this study show that elastin plays an important role in the mechanical properties and fiber structure stability of patellar tendon, which supplements the structure-function relationship information of patellar tendon. The established constitutive model is of great significance to the prediction, repair and replacement of patellar tendon injury. In addition, human patellar tendon has a higher elastin content, so the results of this study can provide supporting information on the natural properties of tendon elastin degradation and guide the development of artificial patellar tendon biomaterials.

17.
Autophagy ; : 1-16, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38818749

RESUMO

Many bacterial pathogens have evolved effective strategies to interfere with the ubiquitination network to evade clearance by the innate immune system. Here, we report that OTUB1, one of the most abundant deubiquitinases (DUBs) in mammalian cells, is subjected to both canonical and noncanonical ubiquitination during Legionella pneumophila infection. The effectors SidC and SdcA catalyze OTUB1 ubiquitination at multiple lysine residues, resulting in its association with a Legionella-containing vacuole. Lysine ubiquitination by SidC and SdcA promotes interactions between OTUB1 and DEPTOR, an inhibitor of the MTORC1 pathway, thus suppressing MTORC1 signaling. The inhibition of MTORC1 leads to suppression of host protein synthesis and promotion of host macroautophagy/autophagy during L. pneumophila infection. In addition, members of the SidE family effectors (SidEs) induce phosphoribosyl (PR)-linked ubiquitination of OTUB1 at Ser16 and Ser18 and block its DUB activity. The levels of the lysine and serine ubiquitination of OTUB1 are further regulated by effectors that function to antagonize the activities of SidC, SdcA and SidEs, including Lem27, DupA, DupB, SidJ and SdjA. Our study reveals an effectors-mediated complicated mechanism in regulating the activity of a host DUB.Abbreviations: BafA1: bafilomycin A1; BMDMs: bone marrow-derived macrophages; DUB: deubiquitinase; Dot/Icm: defective for organelle trafficking/intracellular multiplication; DEPTOR: DEP domain containing MTOR interacting protein; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; L. pneumophila: Legionella pneumophila; LCV: Legionella-containing vacuole; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MOI: multiplicity of infection; MTORC1: mechanistic target of rapamycin kinase complex 1; OTUB1: OTU deubiquitinase, ubiquitin aldehyde binding 1; PR-Ub: phosphoribosyl (PR)-linked ubiquitin; PTM: posttranslational modification; SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; SidEs: SidE family effectors; Ub: ubiquitin.

18.
Nat Microbiol ; 9(6): 1566-1578, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38649411

RESUMO

The cyclic-oligonucleotide-based anti-phage signalling system (CBASS) is a type of innate prokaryotic immune system. Composed of a cyclic GMP-AMP synthase (cGAS) and CBASS-associated proteins, CBASS uses cyclic oligonucleotides to activate antiviral immunity. One major class of CBASS contains a homologue of eukaryotic ubiquitin-conjugating enzymes, which is either an E1-E2 fusion or a single E2. However, the functions of single E2s in CBASS remain elusive. Here, using biochemical, genetic, cryo-electron microscopy and mass spectrometry investigations, we discover that the E2 enzyme from Serratia marcescens regulates cGAS by imitating the ubiquitination cascade. This includes the processing of the cGAS C terminus, conjugation of cGAS to a cysteine residue, ligation of cGAS to a lysine residue, cleavage of the isopeptide bond and poly-cGASylation. The poly-cGASylation activates cGAS to produce cGAMP, which acts as an antiviral signal and leads to cell death. Thus, our findings reveal a unique regulatory role of E2 in CBASS.


Assuntos
Nucleotidiltransferases , Enzimas de Conjugação de Ubiquitina , Ubiquitinação , Enzimas de Conjugação de Ubiquitina/metabolismo , Enzimas de Conjugação de Ubiquitina/genética , Enzimas de Conjugação de Ubiquitina/química , Nucleotidiltransferases/metabolismo , Nucleotidiltransferases/genética , Nucleotidiltransferases/química , Transdução de Sinais , Nucleotídeos Cíclicos/metabolismo , Bacteriófagos/genética , Bacteriófagos/enzimologia , Ubiquitina/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Humanos , Microscopia Crioeletrônica , Imunidade Inata
20.
J Ethnopharmacol ; 330: 118229, 2024 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-38670403

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Thymus quinquecostatus Celak., a member of thymus genus in Lamiaceae family, has been used as a folk medicine for relieving exterior syndrome and alleviating pain in China. The polyphenol-rich fraction (PRF) derived from Thymus quinquecostatus Celak. had been validated that it can protect cerebral ischemia-reperfusion injury (CIRI) by activating Keap1/Nrf2/HO-1 signaling pathway. AIM OF THIS STUDY: To explore effective components and their pharmacokinetic and pharmacodynamic characteristics as well as possible mechanisms of PRF in treating CIRI. MATERIALS AND METHODS: Normal treated group (NTG) and tMCAO model treated group (MTG) rats were administrated PRF intragastrically. The prototype components and metabolites of PRF in plasma and brain were analyzed by the UPLC-Q-Exactive Orbitrap MSn method. Subsequently, the pharmacokinetics properties of indicative components were performed based on HPLC-QQQ-MS/MS. SOD and LDH activities were determined to study the pharmacodynamic (PD) properties of PRF. The PK-PD relationship of PRF was constructed. In addition, the effect of PRF on endogenous metabolites in plasma and brain was investigated using metabolomic method. RESULTS: Salvianic acid A, caffeic acid, rosmarinic acid, scutellarin, and apigenin-7-O-glucuronide were selected as indicative components based on metabolic analysis. The non-compartmental parameters were calculated for indicative components in plasma and brain of NTG and MTG rats. Furthermore, single-component and multi-component PK-PD modeling involved Emax, Imax PD models for effect indexes were fitted as well as ANN models were established, which indicated that these components can work together to regulate SOD and LDH activities in plasma and SOD activity in brain tissue to improve CIRI. Additionally, PRF may ameliorate CIRI by regulating the disorder of endogenous metabolites in lipid metabolism, amino acid metabolism, and purine metabolism pathways in vivo, among which lipid metabolism and purine metabolism are closely related to oxidative stress. CONCLUSION: The PK-PD properties of effect substances and mechanisms of PRF anti-CIRI were further elaborated. The findings provide a convincing foundation for the application of T. quinquecostatus Celak. in the maintenance of human health disorders.


Assuntos
Metabolômica , Polifenóis , Ratos Sprague-Dawley , Traumatismo por Reperfusão , Thymus (Planta) , Animais , Masculino , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Thymus (Planta)/química , Polifenóis/farmacologia , Polifenóis/farmacocinética , Ratos , Infarto da Artéria Cerebral Média/tratamento farmacológico , Extratos Vegetais/farmacologia , Extratos Vegetais/farmacocinética , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Modelos Animais de Doenças , Isquemia Encefálica/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/farmacocinética , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/farmacocinética
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