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1.
Aging Cell ; : e14151, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38529797

RESUMO

Classical genetic analysis is invaluable for understanding the genetic interactions underlying specific phenotypes, but requires laborious and subjective experiments to characterize polygenic and quantitative traits. Contrarily, transcriptomic analysis enables the simultaneous and objective identification of multiple genes whose expression changes are associated with specific phenotypes. Here, we conducted transcriptomic analysis of genes crucial for longevity using datasets with daf-2/insulin/IGF-1 receptor mutant Caenorhabditis elegans. Our analysis unraveled multiple epistatic relationships at the transcriptomic level, in addition to verifying genetically established interactions. Our combinatorial analysis also revealed transcriptomic changes associated with longevity conferred by daf-2 mutations. In particular, we demonstrated that the extent of lifespan changes caused by various mutant alleles of the longevity transcription factor daf-16/FOXO matched their effects on transcriptomic changes in daf-2 mutants. We identified specific aging-regulating signaling pathways and subsets of structural and functional RNA elements altered by different genes in daf-2 mutants. Lastly, we elucidated the functional cooperation between several longevity regulators, based on the combination of transcriptomic and molecular genetic analysis. These data suggest that different biological processes coordinately exert their effects on longevity in biological networks. Together our work demonstrates the utility of transcriptomic dissection analysis for identifying important genetic interactions for physiological processes, including aging and longevity.

2.
Mol Cells ; 47(4): 100047, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38508494

RESUMO

Aging is accompanied by the gradual deregulation of the transcriptome. However, whether age-dependent changes in the transcriptome are evolutionarily conserved or diverged remains largely unexplored. Here, we performed a meta-analysis examining the age-dependent changes in the transcriptome using publicly available datasets of 11 representative metazoans, ranging from Caenorhabditis elegans to humans. To identify the transcriptomic changes associated with aging, we analyzed various aspects of the transcriptome, including genome composition, RNA processing, and functional consequences. The use of introns and novel splice sites tended to increase with age, particularly in the brain. In addition, our analysis suggests that the age-dependent accumulation of premature termination codon-containing transcripts is a common feature of aging across multiple animal species. Using C. elegans as a test model, we showed that several splicing factors that are evolutionarily conserved and age-dependently downregulated were required to maintain a normal lifespan. Thus, aberrant RNA processing appears to be associated with aging and a short lifespan in various species.

3.
J Hematol Oncol ; 17(1): 12, 2024 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-38515194

RESUMO

Cancer early detection and treatment response prediction continue to pose significant challenges. Cancer liquid biopsies focusing on detecting circulating tumor cells (CTCs) and DNA (ctDNA) have shown enormous potential due to their non-invasive nature and the implications in precision cancer management. Recently, liquid biopsy has been further expanded to profile glycoproteins, which are the products of post-translational modifications of proteins and play key roles in both normal and pathological processes, including cancers. The advancements in chemical and mass spectrometry-based technologies and artificial intelligence-based platforms have enabled extensive studies of cancer and organ-specific changes in glycans and glycoproteins through glycomics and glycoproteomics. Glycoproteomic analysis has emerged as a promising tool for biomarker discovery and development in early detection of cancers and prediction of treatment efficacy including response to immunotherapies. These biomarkers could play a crucial role in aiding in early intervention and personalized therapy decisions. In this review, we summarize the significant advance in cancer glycoproteomic biomarker studies and the promise and challenges in integration into clinical practice to improve cancer patient care.


Assuntos
Inteligência Artificial , Neoplasias , Humanos , Neoplasias/diagnóstico , Biomarcadores Tumorais/análise , Glicoproteínas/análise , Glicoproteínas/metabolismo , Biópsia Líquida , Proteoma
4.
Mol Cells ; 47(2): 100011, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38242235

RESUMO

Online application for survival analysis (OASIS) and its update, OASIS 2, have been widely used for survival analysis in biological and medical sciences. Here, we provide a portable version of OASIS, an all-in-one offline suite, to facilitate secure survival analysis without uploading the data to online servers. OASIS portable provides a virtualized and isolated instance of the OASIS 2 webserver, operating on the users' personal computers, and enables user-friendly survival analysis without internet connection and security issues.


Assuntos
Internet , Análise de Sobrevida
5.
Mol Cells ; 46(11): 664-671, 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-37968980

RESUMO

The proper maintenance of mRNA quality that is regulated by diverse surveillance pathways is essential for cellular homeostasis and is highly conserved among eukaryotes. Here, we review findings regarding the role of mRNA quality control in the aging and longevity of Caenorhabditis elegans, an outstanding model for aging research. We discuss the recently discovered functions of the proper regulation of nonsense-mediated mRNA decay, ribosome-associated quality control, and mRNA splicing in the aging of C. elegans. We describe how mRNA quality control contributes to longevity conferred by various regimens, including inhibition of insulin/insulin-like growth factor 1 (IGF-1) signaling, dietary restriction, and reduced mechanistic target of rapamycin signaling. This review provides valuable information regarding the relationship between the mRNA quality control and aging in C. elegans, which may lead to insights into healthy longevity in complex organisms, including humans.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Humanos , Caenorhabditis elegans/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Envelhecimento/genética , Longevidade/genética , Insulina/metabolismo
6.
Case Rep Oncol ; 16(1): 1087-1094, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37900814

RESUMO

Capillary leak syndrome is a rare life-threatening disorder of acute endothelial hyperpermeability. It consists of initial fluid extravasation resulting in hypotension, hypoalbuminemia, and hemoconcentration, followed by noncardiogenic pulmonary edema from rapid fluid remobilization into intravascular compartment. Drug-induced etiology is an important diagnostic consideration in cancer patients, particularly with use of antimetabolites, immunostimulants, and monoclonal antibodies. Sorafenib-mediated capillary leak syndrome has never been reported. Here, we present the case of a 29-year-old female patient with a desmoid tumor of the thigh, who was admitted for acute hypoxic respiratory failure after recent initiation of sorafenib. She was found to have extensive pulmonary edema, bilateral pleural effusions, and hemoconcentration, all of which stabilized on supportive care with noninvasive mechanical ventilation and intravenous diuresis. Her infectious and cardiac work-up were negative. Given the temporal relationship between sorafenib use and symptom onset as well as a lack of an alternative etiology of her findings, patient was deemed to have sorafenib-induced acute capillary leak syndrome. Importantly, she did not become hypotensive prior to or during this hospitalization. To our knowledge, we reported for the first time an atypical presentation of acute capillary leak syndrome due to sorafenib use without hemodynamic instability.

7.
Life Sci Alliance ; 6(8)2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37311584

RESUMO

SLIT/ROBO signaling impacts many aspects of tissue development and homeostasis, in part, through the regulation of cell growth and proliferation. Recent studies have also linked SLIT/ROBO signaling to the regulation of diverse phagocyte functions. However, the mechanisms by which SLIT/ROBO signaling acts at the nexus of cellular growth control and innate immunity remain enigmatic. Here, we show that SLIT2-mediated activation of ROBO1 leads to inhibition of mTORC1 kinase activity in macrophages, leading to dephosphorylation of its downstream targets, including transcription factor EB and ULK1. Consequently, SLIT2 augments lysosome biogenesis, potently induces autophagy, and robustly promotes the killing of bacteria within phagosomes. Concordant with these results, we demonstrate decreased lysosomal content and accumulated peroxisomes in the spinal cords of embryos from Robo1 -/- , Robo2 -/- double knockout mice. We also show that impediment of auto/paracrine SLIT-ROBO signaling axis in cancer cells leads to hyperactivation of mTORC1 and inhibition of autophagy. Together, these findings elucidate a central role of chemorepellent SLIT2 in the regulation of mTORC1 activity with important implications for innate immunity and cancer cell survival.


Assuntos
Proteínas do Tecido Nervoso , Receptores Imunológicos , Animais , Camundongos , Proteínas do Tecido Nervoso/genética , Receptores Imunológicos/genética , Lisossomos , Bactérias , Alvo Mecanístico do Complexo 1 de Rapamicina
8.
J Immunother Cancer ; 10(9)2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36096533

RESUMO

BACKGROUND: Immune checkpoint blockade (ICB) has revolutionized cancer immunotherapy. However, most patients with cancer fail to respond clinically. One potential reason is the accumulation of immunosuppressive transforming growth factor ß (TGFß) in the tumor microenvironment (TME). TGFß drives cancer immune evasion in part by inducing regulatory T cells (Tregs) and limiting CD8+ T cell function. Glycoprotein-A repetitions predominant (GARP) is a cell surface docking receptor for activating latent TGFß1, TGFß2 and TGFß3, with its expression restricted predominantly to effector Tregs, cancer cells, and platelets. METHODS: We investigated the role of GARP in human patients with cancer by analyzing existing large databases. In addition, we generated and humanized an anti-GARP monoclonal antibody and evaluated its antitumor efficacy and underlying mechanisms of action in murine models of cancer. RESULTS: We demonstrate that GARP overexpression in human cancers correlates with a tolerogenic TME and poor clinical response to ICB, suggesting GARP blockade may improve cancer immunotherapy. We report on a unique anti-human GARP antibody (named PIIO-1) that specifically binds the ligand-interacting domain of all latent TGFß isoforms. PIIO-1 lacks recognition of GARP-TGFß complex on platelets. Using human LRRC32 (encoding GARP) knock-in mice, we find that PIIO-1 does not cause thrombocytopenia; is preferentially distributed in the TME; and exhibits therapeutic efficacy against GARP+ and GARP- cancers, alone or in combination with anti-PD-1 antibody. Mechanistically, PIIO-1 treatment reduces canonical TGFß signaling in tumor-infiltrating immune cells, prevents T cell exhaustion, and enhances CD8+ T cell migration into the TME in a C-X-C motif chemokine receptor 3 (CXCR3)-dependent manner. CONCLUSION: GARP contributes to multiple aspects of immune resistance in cancer. Anti-human GARP antibody PIIO-1 is an efficacious and safe strategy to block GARP-mediated LTGFß activation, enhance CD8+ T cell trafficking and functionality in the tumor, and overcome primary resistance to anti-PD-1 ICB. PIIO-1 therefore warrants clinical development as a novel cancer immunotherapeutic.


Assuntos
Neoplasias , Microambiente Tumoral , Animais , Linfócitos T CD8-Positivos/metabolismo , Glicoproteínas , Humanos , Inibidores de Checkpoint Imunológico , Proteínas de Membrana , Camundongos , Fator de Crescimento Transformador beta/metabolismo
9.
iScience ; 25(8): 104717, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35880048

RESUMO

The cancer research field is finally starting to unravel the mystery behind why males have a higher incidence and mortality rate than females for nearly all cancer types of the non-reproductive systems. Here, we explain how sex - specifically sex chromosomes and sex hormones - drives differential adaptive immunity across immune-related disease states including cancer, and why males are consequently more predisposed to tumor development. We highlight emerging data on the roles of cell-intrinsic androgen receptors in driving CD8+ T cell dysfunction or exhaustion in the tumor microenvironment and summarize ongoing clinical efforts to determine the impact of androgen blockade on cancer immunotherapy. Finally, we outline a framework for future research in cancer biology and immuno-oncology, underscoring the importance of a holistic research approach to understanding the mechanisms of sex dimorphisms in cancer, so sex will be considered as an imperative factor for guiding treatment decisions in the future.

10.
Sci Immunol ; 7(73): eabq2630, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35420889

RESUMO

Sex bias exists in the development and progression of nonreproductive organ cancers, but the underlying mechanisms are enigmatic. Studies so far have focused largely on sexual dimorphisms in cancer biology and socioeconomic factors. Here, we establish a role for CD8+ T cell-dependent antitumor immunity in mediating sex differences in tumor aggressiveness, which is driven by the gonadal androgen but not sex chromosomes. A male bias exists in the frequency of intratumoral antigen-experienced Tcf7/TCF1+ progenitor exhausted CD8+ T cells that are devoid of effector activity as a consequence of intrinsic androgen receptor (AR) function. Mechanistically, we identify a novel sex-specific regulon in progenitor exhausted CD8+ T cells and a pertinent contribution from AR as a direct transcriptional transactivator of Tcf7/TCF1. The T cell-intrinsic function of AR in promoting CD8+ T cell exhaustion in vivo was established using multiple approaches including loss-of-function studies with CD8-specific Ar knockout mice. Moreover, ablation of the androgen-AR axis rewires the tumor microenvironment to favor effector T cell differentiation and potentiates the efficacy of anti-PD-1 immune checkpoint blockade. Collectively, our findings highlight androgen-mediated promotion of CD8+ T cell dysfunction in cancer and imply broader opportunities for therapeutic development from understanding sex disparities in health and disease.


Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Androgênios , Animais , Diferenciação Celular , Feminino , Masculino , Camundongos , Sexismo , Microambiente Tumoral
11.
Plant Cell Physiol ; 62(9): 1446-1459, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34155514

RESUMO

Trichomes are hair-like structures that are essential for abiotic and biotic stress responses. Tomato Hair (H), encoding a C2H2 zinc finger protein, was found to regulate the multicellular trichomes on stems. Here, we characterized Solyc10g078990 (hereafter Hair2, H2), its closest homolog, to examine whether it was involved in trichome development. The H2 gene was highly expressed in the leaves, and its protein contained a single C2H2 domain and was localized to the nucleus. The number and length of type I trichomes on the leaves and stems of knock-out h2 plants were reduced when compared to the wild-type, while overexpression increased their number and length. An auto-activation test with various truncated forms of H2 using yeast two-hybrid (Y2H) suggested that H2 acts as a transcriptional regulator or co-activator and that its N-terminal region is important for auto-activation. Y2H and pull-down analyses showed that H2 interacts with Woolly (Wo), which regulates the development of type I trichomes in tomato. Luciferase complementation imaging assays confirmed that they had direct interactions, implying that H2 and Wo function together to regulate the development of trichomes. These results suggest that H2 has a role in the initiation and elongation of type I trichomes in tomato.


Assuntos
Dedos de Zinco CYS2-HIS2/fisiologia , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Caules de Planta/crescimento & desenvolvimento , Solanum lycopersicum/genética , Tricomas/crescimento & desenvolvimento , Solanum lycopersicum/metabolismo , Folhas de Planta/genética , Proteínas de Plantas/metabolismo , Caules de Planta/genética , Tricomas/genética
12.
Nucl Med Mol Imaging ; 54(4): 163-167, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32831961

RESUMO

The dramatic spread of Coronavirus Disease 2019 (COVID-19) has profound impacts on every continent and life. Due to human-to-human transmission of COVID-19, nuclear medicine staffs also cannot escape the risk of infection from workplaces. Every staff in the nuclear medicine department must prepare for and respond to COVID-19 pandemic which tailored to the characteristics of our profession. This article provided the guidance prepared by the Korean Society of Nuclear Medicine (KSNM) in cooperation with the Korean Society of Infectious Disease (KSID) and Korean Society for Healthcare-Associated Infection Control and Prevention (KOSHIC) in managing the COVID-19 pandemic for the nuclear medicine department. We hope that this guidance will support every practice in nuclear medicine during this chaotic period.

13.
Cancer Res ; 79(6): 1178-1190, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30674536

RESUMO

Activated regulatory T (Treg) cells express the surface receptor glycoprotein-A repetitions predominant (GARP), which binds and activates latent TGFß. How GARP modulates Treg function in inflammation and cancer remains unclear. Here we demonstrate that loss of GARP in Treg cells leads to spontaneous inflammation with highly activated CD4+ and CD8+ T cells and development of enteritis. Treg cells lacking GARP were unable to suppress pathogenic T-cell responses in multiple models of inflammation, including T-cell transfer colitis. GARP-/- Treg cells were significantly reduced in the gut and exhibited a reduction in CD103 expression, a colon-specific migratory marker. In the colitis-associated colon cancer model, GARP on Treg cells dampened immune surveillance, and mice with GARP-/- Treg cells exhibited improved antitumor immunity. Thus, GARP empowers the functionality of Treg cells and their tissue-specific accumulation, highlighting the importance of cell surface TGFß in Treg function and GARP as a potential therapeutic target for colorectal cancer therapy.Significance: These findings uncover functions of membrane-bound TGFß and GARP that tune the activity of Treg cells, highlighting a potential treatment strategy in autoimmune diseases and cancer.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Colite/imunologia , Neoplasias do Colo/imunologia , Tolerância Imunológica/imunologia , Inflamação/imunologia , Proteínas de Membrana/fisiologia , Linfócitos T Reguladores/imunologia , Animais , Apoptose , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Proliferação de Células , Colite/metabolismo , Colite/patologia , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Feminino , Humanos , Inflamação/metabolismo , Inflamação/patologia , Células Jurkat , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais , Linfócitos T Reguladores/metabolismo , Linfócitos T Reguladores/patologia
15.
Cancer Epidemiol Biomarkers Prev ; 27(10): 1176-1185, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30049843

RESUMO

Background: Remarkable discrepancy exists in outcomes between men and women for multiple malignancies. We sought to expose sex differences in using platelet count and neutrophil-to-lymphocyte ratio (NLR) to predict overall survival for select cancer types with focus on head and neck squamous cell carcinoma (HNSCC).Methods: Peripheral blood samples from 9,365 patients seen in a tertiary teaching hospital with nine different primary tumors were retrospectively examined. HNSCC RNA-sequencing data from The Cancer Genome Atlas were analyzed by two computational means [Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) and Estimation of Stromal and Immune cells in Malignant Tumor tissues using Expression data (ESTIMATE)] to extend our observations to the tumor microenvironment.Results: For HNSCC, platelet count was more predictive of overall survival for males [log-rank test: HR = 1.809; 95% confidence interval (CI), 1.461-2.239 vs. HR = 1.287; 95% CI, 0.8901-1.861], whereas NLR was more predictive for females (HR = 2.627; 95% CI, 1.716-4.02 vs. HR = 1.261; 95% CI, 0.998-1.593). For females, lymphocyte count was more associated with survival than neutrophil count (multivariate Cox regression: P = 0.0015 vs. P = 0.7476). Both CIBERSORT (P = 0.0061) and ESTIMATE (P = 0.022) revealed greater immune infiltration in females. High tumor infiltration by T lymphocytes was more strikingly associated with survival in females (HR = 0.20, P = 0.0281) than in males (HR = 0.49, P = 0.0147).Conclusions: This is the first study to comprehensively demonstrate sex bias in the clinical utility of platelet, granulocyte, and lymphocyte counts as biomarkers to prognosticate HNSCC patients.Impact: This work emphasizes the necessity to consider sex in appraising inflammatory markers for cancer risk stratification. Cancer Epidemiol Biomarkers Prev; 27(10); 1176-85. ©2018 AACR.


Assuntos
Biomarcadores Tumorais/análise , Carcinoma de Células Escamosas/patologia , Neoplasias de Cabeça e Pescoço/patologia , Mediadores da Inflamação/metabolismo , Linfócitos/patologia , Neutrófilos/patologia , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/terapia , Terapia Combinada , Feminino , Seguimentos , Neoplasias de Cabeça e Pescoço/imunologia , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Fatores Sexuais , Taxa de Sobrevida
16.
J Hematol Oncol ; 10(1): 12, 2017 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-28077173

RESUMO

Cluster of differentiation 47 (CD47) (also known as integrin-associated protein) is a ubiquitously expressed glycoprotein of the immunoglobulin superfamily that plays a critical role in self-recognition. Various solid and hematologic cancers exploit CD47 expression in order to evade immunological eradication, and its overexpression is clinically correlated with poor prognoses. One essential mechanism behind CD47-mediated immune evasion is that it can interact with signal regulatory protein-alpha (SIRPα) expressed on myeloid cells, causing phosphorylation of the SIRPα cytoplasmic immunoreceptor tyrosine-based inhibition motifs and recruitment of Src homology 2 domain-containing tyrosine phosphatases to ultimately result in delivering an anti-phagocytic-"don't eat me"-signal. Given its essential role as a negative checkpoint for innate immunity and subsequent adaptive immunity, CD47-SIRPα axis has been explored as a new target for cancer immunotherapy and its disruption has demonstrated great therapeutic promise. Indeed, CD47 blocking antibodies have been found to decrease primary tumor size and/or metastasis in various pre-clinical models. In this review, we highlight the various functions of CD47, discuss anti-tumor responses generated by both the innate and adaptive immune systems as a consequence of administering anti-CD47 blocking antibody, and finally elaborate on the clinical potential of CD47 blockade. We argue that CD47 is a checkpoint molecule for both innate and adaptive immunity for tumor evasion and is thus a promising target for cancer immunotherapy.


Assuntos
Antígeno CD47/imunologia , Imunidade Inata , Evasão Tumoral/imunologia , Imunidade Adaptativa , Antígenos de Diferenciação/metabolismo , Antígeno CD47/metabolismo , Humanos , Imunoterapia/métodos , Receptores Imunológicos/metabolismo
17.
Korean J Fam Med ; 37(3): 156-63, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27274386

RESUMO

BACKGROUND: Colonoscopy is a very effective and essential examination to diagnose colorectal cancer; however, many patients experience discomfort due to post-examination abdominal pain, which reduces colonoscopy compliance. This study was conducted to determine methods for reducing post-colonoscopic abdominal pain. METHODS: We conducted a randomized controlled study of 405 male and female adults who visited Hana General Hospital in Cheongju. We surveyed general characteristics, history of colonoscopy, and other related factors, then categorized examinees into 5 groups (0-5) according to the site of scope reinsertion. Pain was measured using a numeric rating scale (NRS). RESULTS: The mean age of examinees in this study was 47.8 years, and 210 participants had prior experience of colonoscopy. No significant difference was observed between variables, with the exception of reinsertion duration (P=0.005). Pain scores were different between performing physicians (P=0.006), and were higher when the subjective level of procedure difficulty was low (P=0.026) in univariate analysis. Pain scores decreased as the reinsertion site became closer to the proximal colon (P<0.001), but there was no significant difference between groups 3 and 4. The results of multiple logistic regression analysis, including univariate analysis, showed that group 1 had 0.48 times, group 2 had 0.38 times, group 3 had 0.09 times, and group 4 had 0.03 times odds ratio (moderate-to-severe pain, NRS ≥4) than control group 0. CONCLUSION: Air decompression by scope reinsertion is an effective way to reduce abdominal pain after colonoscopy. Removing air when the reinserted scope approaches the hepatic flexure seems to be the most effective method to reduce post-colonoscopic pain.

18.
J Infect Dis ; 211(7): 1185-95, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25281757

RESUMO

The Gram-positive bacterium Listeria monocytogenes is a facultative intracellular pathogen whose virulence depends on its ability to spread from cell to cell within an infected host. Although the actin-related protein 2/3 (Arp2/3) complex is necessary and sufficient for Listeria actin tail assembly, previous studies suggest that other actin polymerization factors, such as formins, may participate in protrusion formation. Here, we show that Arp2/3 localized to only a minor portion of the protrusion. Moreover, treatment of L. monocytogenes-infected HeLa cells with a formin FH2-domain inhibitor significantly reduced protrusion length. In addition, the Diaphanous-related formins 1-3 (mDia1-3) localized to protrusions, and knockdown of mDia1, mDia2, and mDia3 substantially decreased cell-to-cell spread of L. monocytogenes. Rho GTPases are known to be involved in formin activation. Our studies also show that knockdown of several Rho family members significantly influenced bacterial cell-to-cell spread. Collectively, these findings identify a Rho GTPase-formin network that is critically involved in the cell-to-cell spread of L. monocytogenes.


Assuntos
Complexo 2-3 de Proteínas Relacionadas à Actina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Transporte/metabolismo , Extensões da Superfície Celular/metabolismo , Listeria monocytogenes/fisiologia , Proteínas rho de Ligação ao GTP/metabolismo , Proteína 2 Relacionada a Actina/genética , Proteína 2 Relacionada a Actina/metabolismo , Complexo 2-3 de Proteínas Relacionadas à Actina/genética , Proteína 3 Relacionada a Actina/genética , Proteína 3 Relacionada a Actina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Transporte/efeitos dos fármacos , Proteínas de Transporte/genética , Extensões da Superfície Celular/efeitos dos fármacos , Extensões da Superfície Celular/ultraestrutura , Forminas , Técnicas de Silenciamento de Genes , Genes Reporter , Células HeLa , Interações Hospedeiro-Patógeno , Humanos , Listeria monocytogenes/patogenicidade , Modelos Biológicos , Estrutura Terciária de Proteína , Tionas/farmacologia , Uracila/análogos & derivados , Uracila/farmacologia , Proteínas rho de Ligação ao GTP/genética
19.
PLoS One ; 8(8): e71015, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23990921

RESUMO

SopB is a type 3 secreted effector with phosphatase activity that Salmonella employs to manipulate host cellular processes, allowing the bacteria to establish their intracellular niche. One important function of SopB is activation of the pro-survival kinase Akt/protein kinase B in the infected host cell. Here, we examine the mechanism of Akt activation by SopB during Salmonella infection. We show that SopB-mediated Akt activation is only partially sensitive to PI3-kinase inhibitors LY294002 and wortmannin in HeLa cells, suggesting that Class I PI3-kinases play only a minor role in this process. However, depletion of PI(3,4) P2/PI(3-5) P3 by expression of the phosphoinositide 3-phosphatase PTEN inhibits Akt activation during Salmonella invasion. Therefore, production of PI(3,4) P2/PI(3-5) P3 appears to be a necessary event for Akt activation by SopB and suggests that non-canonical kinases mediate production of these phosphoinositides during Salmonella infection. We report that Class II PI3-kinase beta isoform, IPMK and other kinases identified from a kinase screen all contribute to Akt activation during Salmonella infection. In addition, the kinases required for SopB-mediated activation of Akt vary depending on the type of infected host cell. Together, our data suggest that Salmonella has evolved to use a single effector, SopB, to manipulate a remarkably large repertoire of host kinases to activate Akt for the purpose of optimizing bacterial replication in its host.


Assuntos
Interações Hospedeiro-Patógeno , Fosfotransferases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Infecções por Salmonella/enzimologia , Infecções por Salmonella/microbiologia , Salmonella typhimurium/metabolismo , Androstadienos/farmacologia , Animais , Proteínas de Bactérias/metabolismo , Cromonas/farmacologia , Fibroblastos/metabolismo , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Células HeLa , Humanos , Camundongos , Morfolinas/farmacologia , Oligonucleotídeos/química , Fosforilação , Plasmídeos/metabolismo , Wortmanina
20.
Nucl Med Mol Imaging ; 45(1): 15-20, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24899973

RESUMO

PURPOSE: Measurement of serum hepatitis B virus surface antigen (HBsAg) levels is important for the management of chronic hepatitis B patients in terms of monitoring response to antiviral therapy. This study aimed to evaluate the diagnostic performance of a new diagnostic kit, which quantitatively measures serum HBsAg level using an immunoradiometric assay (IRMA)-based method. Measurements were compared with those obtained using a chemiluminescent microparticle immunoassay (CMIA)-based method. METHODS: The blood samples of 96 patients with chronic hepatitis B were used in this study. Copy numbers of serum hepatitis B virus (HBV) DNA were determined in 23 of these samples. The correlation between and the concordance of IRMA and CMIA results were determined using Pearson's correlation coefficients. P values of 0.05 were considered to be statistically significant throughout. RESULTS: Laboratory diagnoses based on IRMA were wholly in agreement with those based on CMIA. Furthermore, serum HBsAg levels by IRMA were found to be highly correlated with those determined by CMIA (correlation coefficient R (2) = 0.838, p < 0.001). Serum HBsAg level and serum HBV DNA copies were found to be linearly related by both methods (R (2) = 0.067, p = 0.316 by IRMA, and R (2) = 0.101, p = 0.215 by CMIA). CONCLUSION: The diagnostic performance of the investigated IRMA method of determining HBsAg levels was found to be comparable with that of a CMIA-based method in chronic hepatitis B patients.

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