RESUMO
INTRODUCTION: Cerebral ischemia-reperfusion injury (CIRI) is a common and debilitating complication of cerebrovascular diseases such as stroke, characterized by mitochondrial dysfunction and cell apoptosis. Unraveling the molecular mechanisms behind these processes is essential for developing effective CIRI treatments. This study investigates the role of RACK1 (receptor for activated C kinase 1) in CIRI and its impact on mitochondrial autophagy. METHODS: We utilized high-throughput transcriptome sequencing and weighted gene co-expression network analysis (WGCNA) to identify core genes associated with CIRI. In vitro experiments used human neuroblastoma SK-N-SH cells subjected to oxygen and glucose deprivation (OGD) to simulate ischemia, followed by reperfusion (OGD/R). RACK1 knockout cells were created using CRISPR/Cas9 technology, and cell viability, apoptosis, and mitochondrial function were assessed. In vivo experiments involved middle cerebral artery occlusion/reperfusion (MCAO/R) surgery in rats, evaluating neurological function and cell apoptosis. RESULTS: Our findings revealed that RACK1 expression increases during CIRI and is protective by regulating mitochondrial autophagy through the PINK1/Parkin pathway. In vitro, RACK1 knockout exacerbated cell apoptosis, while overexpression of RACK1 reversed this process, enhancing mitochondrial function. In vivo, RACK1 overexpression reduced cerebral infarct volume and improved neurological deficits. The regulatory role of RACK1 depended on the PINK1/Parkin pathway, with RACK1 knockout inhibiting PINK1 and Parkin expression, while RACK1 overexpression restored them. CONCLUSION: This study demonstrates that RACK1 safeguards against neural damage in CIRI by promoting mitochondrial autophagy through the PINK1/Parkin pathway. These findings offer crucial insights into the regulation of mitochondrial autophagy and cell apoptosis by RACK1, providing a promising foundation for future CIRI treatments.
Assuntos
Autofagia , Mitocôndrias , Proteínas Quinases , Receptores de Quinase C Ativada , Traumatismo por Reperfusão , Ubiquitina-Proteína Ligases , Animais , Humanos , Ratos , Apoptose/fisiologia , Autofagia/fisiologia , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Linhagem Celular Tumoral , Infarto da Artéria Cerebral Média/patologia , Infarto da Artéria Cerebral Média/metabolismo , Mitocôndrias/metabolismo , Proteínas de Neoplasias , Neuroproteção/fisiologia , Proteínas Quinases/metabolismo , Proteínas Quinases/genética , Ratos Sprague-Dawley , Receptores de Quinase C Ativada/metabolismo , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Transdução de Sinais/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genéticaRESUMO
CD4+ T cells are central mediators of protective immunity to blood-stage malaria, particularly for their capacity in orchestrating germinal center reaction and generating parasite-specific high-affinity antibodies. T follicular helper (Tfh) cells are predominant CD4+ effector T cell subset implicated in these processes, yet the factors and detailed mechanisms that assist Tfh cell development and function during Plasmodium infection are largely undefined. Here we provide evidence that receptor for activated C kinase 1 (RACK1), an adaptor protein of various intracellular signals, is not only important for CD4+ T cell expansion as previously implied but also plays a prominent role in Tfh cell differentiation and function during blood-stage Plasmodium yoelii 17XNL infection. Consequently, RACK1 in CD4+ T cells contributes significantly to germinal center formation, parasite-specific IgG production, and host resistance to the infection. Mechanistic exploration detects specific interaction of RACK1 with STAT3 in P. yoelii 17XNL-responsive CD4+ T cells, ablation of RACK1 leads to defective STAT3 phosphorylation, accompanied by substantially lower amount of STAT3 protein in CD4+ T cells, whereas retroviral overexpression of RACK1 or STAT3 in RACK1-deficient CD4+ T cells greatly restores STAT3 activity and Bcl-6 expression under the Tfh polarization condition. Further analyses suggest RACK1 positively regulates STAT3 stability by inhibiting the ubiquitin-proteasomal degradation process, thus promoting optimal STAT3 activity and Bcl-6 induction during Tfh cell differentiation. These findings uncover a novel mechanism by which RACK1 participates in posttranslational regulation of STAT3, Tfh cell differentiation, and subsequent development of anti-Plasmodium humoral immunity.
Assuntos
Diferenciação Celular , Malária , Plasmodium yoelii , Receptores de Quinase C Ativada , Fator de Transcrição STAT3 , Células T Auxiliares Foliculares , Animais , Receptores de Quinase C Ativada/metabolismo , Fator de Transcrição STAT3/metabolismo , Malária/imunologia , Malária/parasitologia , Camundongos , Plasmodium yoelii/imunologia , Células T Auxiliares Foliculares/imunologia , Células T Auxiliares Foliculares/metabolismo , Camundongos Endogâmicos C57BL , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Camundongos Knockout , Centro Germinativo/imunologiaRESUMO
BACKGROUND: Renal fibrosis is a prevalent manifestation of chronic kidney disease (CKD), and effective treatments for this disease are currently lacking. Myofibroblasts, which originate from interstitial fibroblasts, aggregate in the renal interstitium, leading to significant accumulation of extracellular matrix and impairment of renal function. The nonreceptor tyrosine kinase c-Abl (encoded by the Abl1 gene) has been implicated in the development of renal fibrosis. However, the precise role of c-Abl in this process and its involvement in fibroblast-myofibroblast transition (FMT) remain poorly understood. METHODS: To investigate the effect of c-Abl in FMT during renal fibrosis, we investigated the expression of c-Abl in fibrotic renal tissues of patients with CKD and mouse models. We studied the phenotypic changes in fibroblast or myofibroblast-specific c-Abl conditional knockout mice. We explored the potential targets of c-Abl in NRK-49F fibroblasts. RESULTS: In this study, fibrotic mouse and cell models demonstrated that c-Abl deficiency in fibroblasts mitigated fibrosis by suppressing fibroblast activation, fibroblast-myofibroblast transition, and extracellular matrix deposition. Mechanistically, c-Abl maintains the stability of the RACK1 protein, which serves as a scaffold for proteins such as c-Abl and focal adhesion kinase at focal adhesions, driving fibroblast activation and differentiation during renal fibrosis. Moreover, specifically targeting c-Abl deletion in renal myofibroblasts could prove beneficial in established kidney fibrosis by reducing RACK1 expression and diminishing the extent of fibrosis. CONCLUSIONS: Our findings suggest that c-Abl plays a pathogenic role in interstitial fibrosis through the regulation of RACK1 protein stabilization and myofibroblast differentiation, suggesting a promising strategy for the treatment of CKD.
Assuntos
Fibroblastos , Fibrose , Miofibroblastos , Proteínas Proto-Oncogênicas c-abl , Receptores de Quinase C Ativada , Transdução de Sinais , Animais , Proteínas Proto-Oncogênicas c-abl/metabolismo , Proteínas Proto-Oncogênicas c-abl/genética , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Humanos , Camundongos , Fibroblastos/metabolismo , Fibroblastos/patologia , Receptores de Quinase C Ativada/genética , Receptores de Quinase C Ativada/metabolismo , Quinase 1 de Adesão Focal/metabolismo , Quinase 1 de Adesão Focal/genética , Rim/patologia , Rim/metabolismo , Masculino , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/genética , Camundongos Knockout , Camundongos Endogâmicos C57BLRESUMO
Plants deploy versatile scaffold proteins to intricately modulate complex cell signaling. Among these, RACK1A (Receptors for Activated C Kinase 1A) stands out as a multifaceted scaffold protein functioning as a central integrative hub for diverse signaling pathways. However, the precise mechanisms by which RACK1A orchestrates signal transduction to optimize seedling development remain largely unclear. Here, we demonstrate that RACK1A facilitates hypocotyl elongation by functioning as a flexible platform that connects multiple key components of light signaling pathways. RACK1A interacts with PHYTOCHROME INTERACTING FACTOR (PIF)3, enhances PIF3 binding to the promoter of BBX11 and down-regulates its transcription. Furthermore, RACK1A associates with ELONGATED HYPOCOTYL 5 (HY5) to repress HY5 biochemical activity toward target genes, ultimately contributing to hypocotyl elongation. In darkness, RACK1A is targeted by CONSTITUTIVELY PHOTOMORPHOGENIC (COP)1 upon phosphorylation and subjected to COP1-mediated degradation via the 26 S proteasome system. Our findings provide new insights into how plants utilize scaffold proteins to regulate hypocotyl elongation, ensuring proper skoto- and photo-morphogenic development.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , Hipocótilo , Receptores de Quinase C Ativada , Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Hipocótilo/crescimento & desenvolvimento , Hipocótilo/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Receptores de Quinase C Ativada/metabolismo , Receptores de Quinase C Ativada/genética , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Transdução de Sinais , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Transdução de Sinal Luminoso , FosforilaçãoRESUMO
Voltage-dependent anion channel 2 (VDAC2) is an important channel protein that plays a crucial role in the host response to viral infection. The receptor for activated C kinase 1 (RACK1) is also a key host factor involved in viral replication. Our previous research revealed that Bombyx mori VDAC2 (BmVDAC2) and B. mori RACK1 (BmRACK1) may interact with Bombyx mori nucleopolyhedrovirus (BmNPV), though the specific molecular mechanism remains unclear. In this study, the interaction between BmVDAC2 and BmRACK1 in the mitochondria was determined by various methods. We found that BmNPV p35 interacts directly with BmVDAC2 rather than BmRACK1. BmNPV infection significantly reduced the expression of BmVDAC2, and activated the mitochondrial apoptosis pathway. Overexpression of BmVDAC2 in BmN cells inhibited BmNPV-induced cytochrome c (cyto c) release, decrease in mitochondrial membrane potential as well as apoptosis. Additionally, the inhibition of cyto c release by BmVDAC2 requires the involvement of BmRACK1 and protein kinase C. Interestingly, overexpression of p35 inhibited cyto c release during mitochondrial apoptosis in a RACK1 and VDAC2-dependent manner. Even the mutant p35, which loses Caspase inhibitory activity, could still bind to VDAC2 and inhibit cyto c release. In summary, our results indicated that BmNPV p35 interacts with the VDAC2-RACK1 complex to regulate apoptosis by inhibiting cyto c release. These findings confirm the interaction between BmVDAC2 and BmRACK1, the interaction between p35 and the VDAC2-RACK1 complex, and a novel target that BmNPV p35 regulates apoptosis in Bombyx mori via interaction with the BmVDAC2-BmRACK1 complex. The result provide an initial exploration of the function of this interaction in the BmNPV-induced mitochondrial apoptosis pathway.
Assuntos
Apoptose , Bombyx , Proteínas de Insetos , Nucleopoliedrovírus , Receptores de Quinase C Ativada , Animais , Bombyx/virologia , Bombyx/metabolismo , Bombyx/genética , Nucleopoliedrovírus/fisiologia , Receptores de Quinase C Ativada/metabolismo , Receptores de Quinase C Ativada/genética , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Canal de Ânion 2 Dependente de Voltagem/metabolismo , Canal de Ânion 2 Dependente de Voltagem/genética , Mitocôndrias/metabolismoRESUMO
ABSCISIC ACID INSENSITIVE5 (ABI5), a key regulator of the abscisic acid (ABA) signalling pathway, plays a fundamental role in seed germination and post-germinative development. However, the molecular mechanism underlying the repression function of ABI5 remains to be elucidated. In this study, we demonstrate that the conserved eukaryotic WD40 repeat protein Receptor for Activated C Kinase 1 (RACK1) is a novel negative regulator of ABI5 in Arabidopsis. The RACK1 loss-of-function mutant is hypersensitive to ABA, while this phenotype is rescued by a mutation in ABI5. Moreover, overexpression of RACK1 suppresses ABI5 transcriptional activation activity for ABI5-targeted genes. RACK1 may also physically interact with ABI5 and facilitate its degradation. Furthermore, we found that RACK1 and the two substrate receptors CUL4-based E3 ligases (DWA1 and DWA2) function together to mediate the turnover of ABI5, thereby efficiently reducing ABA signalling in seed germination and post-germinative growth. In addition, molecular analyses demonstrated that ABI5 may bind to the promoter of RACK1 to repress its expression. Collectively, our findings suggest that RACK1 and ABI5 might form a feedback loop to regulate the homeostasis of ABA signalling in acute seed germination and early plant development.
Assuntos
Ácido Abscísico , Proteínas de Arabidopsis , Arabidopsis , Germinação , Receptores de Quinase C Ativada , Sementes , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Receptores de Quinase C Ativada/metabolismo , Receptores de Quinase C Ativada/genética , Sementes/crescimento & desenvolvimento , Sementes/genética , Sementes/metabolismo , Sementes/fisiologia , Ácido Abscísico/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Regulação da Expressão Gênica de Plantas , Transdução de SinaisRESUMO
Anorectal malformation (ARM), a common congenital anomaly of the digestive tract, is a result of insufficient elongation of the urorectal septum. The cytoplasmic protein Receptor of Activated C-Kinase 1 (Rack1) is involved in embryonic neural development; however, its role in embryonic digestive tract development and ARM formation is unexplored. Our study explored the hindgut development and cell death mechanisms in ARM-affected rats using spatial transcriptome analysis. We induced ARM in rats by administering ethylenethiourea via gavage on gestational day (GD) 10. On GDs 14-16, embryos from both normal and ARM groups underwent spatial transcriptome sequencing, which identified key genes and signalling pathways. Rack1 exhibited significant interactions among differentially expressed genes on GDs 15 and 16. Reduced Rack1 expression in the ARM-affected hindgut, verified by Rack1 silencing in intestinal epithelial cells, led to increased P38 phosphorylation and activation of the MAPK signalling pathway. The suppression of this pathway downregulated Nqo1 and Gpx4 expression, resulting in elevated intracellular levels of ferrous ions, reactive oxygen species (ROS) and lipid peroxides. Downregulation of Gpx4 expression in the ARM hindgut, coupled with Rack1 co-localisation and consistent mitochondrial morphology, indicated ferroptosis. In summary, Rack1, acting as a hub gene, modulates ferrous ions, lipid peroxides, and ROS via the P38-MAPK/Nqo1/Gpx4 axis. This modulation induces ferroptosis in intestinal epithelial cells, potentially influencing hindgut development during ARM onset.
Assuntos
Malformações Anorretais , Ferroptose , Receptores de Quinase C Ativada , Transcriptoma , Animais , Receptores de Quinase C Ativada/metabolismo , Receptores de Quinase C Ativada/genética , Ferroptose/genética , Ferroptose/efeitos dos fármacos , Ratos , Malformações Anorretais/genética , Malformações Anorretais/metabolismo , Malformações Anorretais/patologia , Feminino , Espécies Reativas de Oxigênio/metabolismo , Ratos Sprague-Dawley , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/genética , Etilenotioureia , Transdução de SinaisRESUMO
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by dysregulation of the expression and processing of the amyloid precursor protein (APP). Protein quality control systems are dedicated to remove faulty and deleterious proteins to maintain cellular protein homeostasis (proteostasis). Identidying mechanisms underlying APP protein regulation is crucial for understanding AD pathogenesis. However, the factors and associated molecular mechanisms regulating APP protein quality control remain poorly defined. In this study, we show that mutant APP with its mitochondrial-targeting sequence ablated exhibited predominant endoplasmic reticulum (ER) distribution and led to aberrant ER morphology, deficits in locomotor activity, and shortened lifespan. We searched for regulators that could counteract the toxicity caused by the ectopic expression of this mutant APP. Genetic removal of the ribosome-associated quality control (RQC) factor RACK1 resulted in reduced levels of ectopically expressed mutant APP. By contrast, gain of RACK1 function increased mutant APP level. Additionally, overexpression of the ER stress regulator (IRE1) resulted in reduced levels of ectopically expressed mutant APP. Mechanistically, the RQC related ATPase VCP/p97 and the E3 ubiquitin ligase Hrd1 were required for the reduction of mutant APP level by IRE1. These factors also regulated the expression and toxicity of ectopically expressed wild type APP, supporting their relevance to APP biology. Our results reveal functions of RACK1 and IRE1 in regulating the quality control of APP homeostasis and mitigating its pathogenic effects, with implications for the understanding and treatment of AD.
Assuntos
Doença de Alzheimer , Precursor de Proteína beta-Amiloide , Proteínas de Drosophila , Endorribonucleases , Receptores de Quinase C Ativada , Animais , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Proteínas Serina-Treonina Quinases , Receptores de Quinase C Ativada/genética , Receptores de Quinase C Ativada/metabolismo , Drosophila melanogaster , Modelos Animais de Doenças , Endorribonucleases/genética , Endorribonucleases/metabolismoRESUMO
BACKGROUND: Dysregulated ubiquitination modification occupies a pivotal role in hepatocellular carcinoma (HCC) tumorigenesis and progression. The ubiquitin aldehyde binding 1 (OTUB1) was aberrantly upregulated and exhibited the pro-tumorigenic function in HCC. However, the underlying mechanisms and responsible targets of OTUB1 remain unclear. METHODS: First, bioinformatics analysis, western blot and immunohistochemistry staining were applied to analyze OTUB1 expression in HCC specimens. Then, immunoprecipitation assay-tandem mass spectrometry (MS) combined with the gene set enrichment analysis (GSEA) was used to explore the downstream target of OTUB1. Co-immunoprecipitation and ubiquitination assays were used to identify the mechanisms involved. Finally, we explored the regulatory effect of MAZ on OTUB1 through ChIP-qPCR and dual-luciferase reporter assay. RESULTS: OTUB1 was broadly elevated in HCC tissues and promoted the proliferation and metastasis of HCC in vitro and in vivo. The receptor for activated C kinase 1 (RACK1) performed as a functional partner of OTUB1 and its hyperactivation was associated with aggressive development and other malignant features in HCC by activating oncogenes transcription. Mechanistically, OTUB1 directly bound to RACK1 at its C-terminal domain and decreased the K48-linked ubiquitination of RACK1 through its non-canonical suppression of ubiquitination activity, which stabilized RACK1 protein levels in HCC cells. Therefore, OTUB1 significantly increased multiple oncogenes expression and activated PI3K/AKT and FAK/ERK signaling in a RACK1-dependent manner in HCC. Moreover, the transcription factor MAZ upregulated OTUB1 expression through identifying a putative response element of OTUB1 promoter area. CONCLUSIONS: Our findings might provide a new therapeutic strategy for HCC by modifying the MAZ-OTUB1-RACK1 axis.
Assuntos
Carcinoma Hepatocelular , Proliferação de Células , Neoplasias Hepáticas , Proteínas de Neoplasias , Receptores de Quinase C Ativada , Ubiquitinação , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Receptores de Quinase C Ativada/metabolismo , Receptores de Quinase C Ativada/genética , Linhagem Celular Tumoral , Animais , Proliferação de Células/genética , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/genética , Masculino , Regulação Neoplásica da Expressão Gênica , Camundongos Nus , Cisteína Endopeptidases/metabolismo , Cisteína Endopeptidases/genética , Feminino , Proteases Específicas de Ubiquitina/metabolismo , Proteases Específicas de Ubiquitina/genética , Pessoa de Meia-Idade , Camundongos , Transdução de Sinais , Camundongos Endogâmicos BALB C , Estabilidade Proteica , Enzimas DesubiquitinantesRESUMO
BACKGROUND: Cholangiocarcinoma (CCA), a primary hepatobiliary malignancy, is characterized by a poor prognosis and a lack of effective treatments. Therefore, the need to explore novel therapeutic approaches is urgent. While the role of Peptidylprolyl Cis/Trans Isomerase, NIMA-Interacting 1 (PIN1) has been extensively studied in various tumor types, its involvement in CCA remains poorly understood. METHODS: In this study, we employed tissue microarray (TMA), reverse transcription-polymerase chain reaction (RT-PCR), and The Cancer Genome Atlas (TCGA) database to assess the expression of PIN1. Through in vitro and in vivo functional experiments, we investigated the impact of PIN1 on the adhesion and metastasis of CCA. Additionally, we explored downstream molecular pathways using RNA-seq, western blotting, co-immunoprecipitation, immunofluorescence, and mass spectrometry techniques. RESULTS: Our findings revealed a negative correlation between PIN1 overexpression and prognosis in CCA tissues. Furthermore, high PIN1 expression promoted CCA cell proliferation and migration. Mechanistically, PIN1 functioned as an oncogene by regulating ANXA2 phosphorylation, thereby promoting CCA adhesion. Notably, the interaction between PIN1 and ANXA2 was facilitated by RACK1. Importantly, pharmacological inhibition of PIN1 using the FDA-approved drug all-trans retinoic acid (ATRA) effectively suppressed the metastatic potential of CCA cells in a nude mouse lung metastasis model. CONCLUSION: Overall, our study emphasizes the critical role of the PIN1/RACK1/ANXA2 complex in CCA growth and functionality, highlighting the potential of targeting PIN1 as a promising therapeutic strategy for CCA.
Assuntos
Anexina A2 , Neoplasias dos Ductos Biliares , Proliferação de Células , Colangiocarcinoma , Camundongos Nus , Peptidilprolil Isomerase de Interação com NIMA , Metástase Neoplásica , Receptores de Quinase C Ativada , Colangiocarcinoma/patologia , Colangiocarcinoma/metabolismo , Colangiocarcinoma/genética , Humanos , Anexina A2/metabolismo , Anexina A2/genética , Linhagem Celular Tumoral , Animais , Neoplasias dos Ductos Biliares/patologia , Neoplasias dos Ductos Biliares/metabolismo , Neoplasias dos Ductos Biliares/genética , Fosforilação , Receptores de Quinase C Ativada/metabolismo , Receptores de Quinase C Ativada/genética , Peptidilprolil Isomerase de Interação com NIMA/metabolismo , Peptidilprolil Isomerase de Interação com NIMA/genética , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/genética , Camundongos , Movimento Celular/genética , Masculino , Regulação Neoplásica da Expressão Gênica , Adesão Celular , Feminino , Camundongos Endogâmicos BALB C , Prognóstico , Pessoa de Meia-IdadeRESUMO
BACKGROUND: Gut epithelium is the first natural barrier against Trichinella spiralis larval invasion, but the mechanism by which larval penetration of gut epithelium is not completely elucidated. Previous studies showed that proteases secreted by T. spiralis intestinal infective larvae (IIL) degraded tight junctions (TJs) proteins of gut epithelium and mediated larval invasion. A new T. spiralis serine proteinase (TsSPc) was identified in the IIL surface proteins and ES proteins, rTsSPc bound to the intestinal epithelial cell (IECs) and promoted larval invasion of IECs. The aim of this study was to characterize the interacted proteins of TsSPc and IECs, and to investigate the molecular mechanisms of TsSPc mediating larval invasion of gut mucosa. METHODOLOGY/PRINCIPAL FINDING: IIFT results showed natural TsSPc was detected in infected murine intestine at 6, 12 hours post infection (hpi) and 3 dpi. The results of GST pull-down, mass spectrometry (MS) and Co-IP indicated that rTsSPc bound and interacted specifically with receptor for activated protein C kinase 1 (RACK1) in Caco-2 cells. rTsSPc did not directly hydrolyze the TJs proteins. qPCR and Western blot showed that rTsSPc up-regulated RACK1 expression, activated MAPK/ERK1/2 pathway, reduced the expression levels of gut TJs (occludin and claudin-1) and adherent protein E-cad, increased the paracellular permeability and damaged the integrity of intestinal epithelial barrier. Moreover, the RACK1 inhibitor HO and ERK1/2 pathway inhibitor PD98059 abolished the rTsSPc activating ERK1/2 pathway, they also inhibited and abrogated the rTsSPc down-regulating expression of occludin, claudin-1 and E-cad in Caco-2 monolayer and infected murine intestine, impeded larval invasion and improved intestinal epithelial integrity and barrier function, reduced intestinal worm burdens and alleviated intestinal inflammation. CONCLUSIONS: rTsSPc bound to RACK1 receptor in gut epithelium, activated MAPK/ERK1/2 pathway, decreased the expression of gut epithelial TJs proteins and disrupted the epithelial integrity, consequently mediated T. spiralis larval invasion of gut epithelium. The results are valuable to understand T. spiralis invasion mechanism, and TsSPc might be regarded as a vaccine target against T. spiralis invasion and infection.
Assuntos
Trichinella spiralis , Triquinelose , Humanos , Animais , Camundongos , Larva/fisiologia , Serina Proteases/genética , Células CACO-2 , Claudina-1/metabolismo , Sistema de Sinalização das MAP Quinases , Ocludina/metabolismo , Proteínas de Helminto/metabolismo , Células Epiteliais/metabolismo , Camundongos Endogâmicos BALB C , Mucosa Intestinal/metabolismo , Receptores de Quinase C Ativada/metabolismo , Proteínas de Neoplasias/genéticaRESUMO
BACKGROUND: Metabolic reprogramming is closely related to the development of gastric cancer (GC), which remains as the fourth leading cause of cancer-related death worldwide. As a tumor suppressor for GC, whether receptor for activated C-kinase 1 (RACK1) play a modulatory role in metabolic reprogramming remains largely unclear. METHODS: GC cell lines and cell-derived xenograft mouse model were used to identify the biological function of RACK1. Flow cytometry and Seahorse assays were applied to examine cell cycle and oxygen consumption rate (OCR), respectively. Western blot, real-time PCR and autophagy double fluorescent assays were utilized to explore the signaling. Immunohistochemistry was performed to detect the expression of RACK1 and other indicators in tissue sections. RESULTS: Loss of RACK1 facilitated the viability, colony formation, cell cycle progression and OCR of GC cells in a glutamine-dependent manner. Further investigation revealed that RACK1 knockdown inhibited the lysosomal degradation of Alanine-serine-cysteine amino acid transporter 2 (ASCT2). Mechanistically, depletion of RACK1 remarkably decreased PTEN expression through up-regulating miR-146b-5p, leading to the activation of AKT/mTOR signaling pathway which dampened autophagy flux subsequently. Moreover, knockdown of ASCT2 could reverse the promotive effect of RACK1 depletion on GC tumor growth both in vitro and in vivo. Tissue microarray confirmed that RACK1 was negatively correlated with the expression of ASCT2 and p62, as well as the phosphorylation of mTOR. CONCLUSION: Together, our results demonstrate that the suppressive function of RACK1 in GC is associated with ASCT2-mediated glutamine metabolism, and imply that targeting RACK1/ASCT2 axis provides potential strategies for GC treatment.
Assuntos
Neoplasias Gástricas , Humanos , Animais , Camundongos , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Glutamina/metabolismo , Linhagem Celular Tumoral , Serina-Treonina Quinases TOR/metabolismo , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Receptores de Quinase C Ativada/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismoRESUMO
Toxoplasma gondii (T. gondii) surface antigen 1 (SAG1) is crucial for tachyzoite invasion into host cells. However, the role of SAG1 in interaction with host cells remains unknown. The primary objective of this study was to analyze and validate the interaction between SAG1 and host cells. RACK1, an intracellular multifunctional protein, was identified as a SAG1 binding partner in host cells. Furthermore, the expression of RACK1 is manipulated by SAG1, and depletion of RACK1 negatively regulated host cell viability. These results imply that through interaction with RACK1, SAG1 preserves the viability of host cells to satisfy the survival needs of T. gondii. Our findings suggest a novel role for SAG1 in intracellular parasitism.
Assuntos
Proteínas de Protozoários , Toxoplasma , Antígenos de Protozoários/genética , Receptores de Quinase C Ativada/genética , Receptores de Quinase C Ativada/metabolismo , Antígenos de Superfície/metabolismo , Anticorpos AntiprotozoáriosRESUMO
Microglial polarization modulation has been considered the potential therapeutic strategy for relieving cognitive impairment in sepsis survivors. Rosmarinic acid (RA), a water-soluble polyphenolic natural compound, processes a strong protective effect on various types of neurological disorders including Parkinson's disease, depression, and anxiety. However, its role and potential molecular mechanisms in sepsis-associated cognitive impairment remain unclear. To investigate the preventive and therapeutic effect of RA on sepsis-associated cognitive impairment and elucidate the potential mechanism of RA on regulating microglial polarization, we established a CLP-induced cognitive impairment model in mice and a lipopolysaccharide-induced microglia polarization cell model in BV-2. RACK1 siRNA was designed to identify the potential molecular mechanism of RACK1 on microglial polarization. The preventive and therapeutic effect of RA on cognitive impairment followed by PET-CT and behavioral tests including open-field test and tail suspension test. RACK1/HIF-1α pathway and microglial morphology in the hippocampus or BV-2 cells were measured. The results showed that RA significantly ameliorated the CLP-induced depressive and anxiety-like behaviors and promoted whole-brain glucose uptake in mice. Moreover, RA markedly improved CLP-induced hippocampal neuron loss and microglial activation by inhibiting microglial M1 polarization. Furthermore, experiments showed RACK1 was involved in the regulation of LPS-induced microglial M1 polarization via HIF-1α, and RA suppressed lipopolysaccharide or sepsis-associated microglial M1 polarization via RACK1/HIF-1α pathway (rescued the decrease of RACK1 and increase of HIF-1α). Taken together, RA could be a potential preventive and therapeutic medication in improving cognitive impairment through RACK1/HIF-1α pathway-regulated microglial polarization.
Assuntos
Disfunção Cognitiva , Ácido Rosmarínico , Sepse , Animais , Camundongos , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Lipopolissacarídeos/toxicidade , Lipopolissacarídeos/metabolismo , Microglia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Receptores de Quinase C Ativada/efeitos dos fármacos , Receptores de Quinase C Ativada/metabolismo , Ácido Rosmarínico/farmacologia , Ácido Rosmarínico/uso terapêutico , Sepse/complicações , Sepse/tratamento farmacológico , Transdução de Sinais , Subunidade alfa do Fator 1 Induzível por Hipóxia/efeitos dos fármacos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismoRESUMO
PURPOSEï¼ To investigate the expression of tissue-active protein kinase C receptor 1 (RACK1) and epithelin glycoprotein 40 (EGP40) in oral squamous cell carcinoma (OSCC) and their relationship with clinicopathological features and prognosis. METHODS: A total of 103 patients with OSCC who were admitted to Shangrao People's Hospital from January 2016 to February 2019 were prospectively selected as the research subjects. All patients underwent radical resection of OSCC and were followed up for 3 years. Immunohistochemistry was used to detect the positive expression levels of RACK1 and EGP40 in cancer tissues and adjacent tissues. The positive expression of RACK1 and EGP40 in cancer tissues and adjacent tissues were compared. The relationship between the positive expression level of RACK1 and EGP40 in cancer tissues of OSCC patients and clinicopathological parameters was analyzed. Factors affecting postoperative recurrence and metastasis in OSCC patients were analyzed. The relationship between the expression of RACK1 and EGP40 in cancer tissues and postoperative disease-free survival of OSCC patients was analyzed. SPSS 18.0 software package was used for statistical analysis of the data. RESULTS: The positive expression rate of RACK1 and EGP40 in cancer tissues was significantly higher than those in adjacent tissues (Pï¼0.05). The positive expression rate of RACK1 and EGP40 in cancer tissues of OSCC patients with poorly differentiated, stage III, cervical lymph node metastasis, and infiltrating vessels was significantly higher than that in patients with moderate and high differentiation, stage II, no cervical lymph node metastasis, and no infiltrating vessels(Pï¼0.05). The positive expression rate of RACK1 in cancer tissue of OSCC patients in T3 stage was significantly higher than that in T2 stage(Pï¼0.05). Cox multivariate regression analysis showed pathological grade (RR=6.290, 95%CI: 2.588-15.287), cervical lymph node metastasis(RR=5.995, 95%CI: 2.467-14.571), RACK1 positive rate (RR=4.495, 95%CI: 1.850-10.925) and EGP40 positive rate (RR=4.559, 95%CI: 1.876-11.079) were factors affecting the recurrence and metastasis of OSCC patients after surgery(Pï¼0.05). The disease-free survival curve of patients with negative expression of RACK1 was significantly better than that of patients with positive expression (Pï¼0.05). The disease-free survival curve of patients with negative expression of EGP40 was significantly better than that of patients with positive expression (Pï¼0.05). CONCLUSIONS: The expression of RACK1 and EGP40 in cancer tissues of OSCC patients is related to clinicopathological parameters and prognosis. Patients with positive expression of RACK1 and EGP40 have a high risk of recurrence and metastasis after surgery.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Humanos , Carcinoma de Células Escamosas/cirurgia , Carcinoma de Células Escamosas/patologia , Granulinas , Metástase Linfática , Neoplasias Bucais/cirurgia , Neoplasias Bucais/patologia , Proteínas de Neoplasias/metabolismo , Prognóstico , Receptores de Quinase C Ativada/metabolismo , Carcinoma de Células Escamosas de Cabeça e PescoçoRESUMO
TAR DNA-binding protein 43 (TDP-43) and Fused in Sarcoma/Translocated in Sarcoma (FUS) are ribonucleoproteins associated with pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Under physiological conditions, TDP-43 and FUS are predominantly localized in the nucleus, where they participate in transcriptional regulation, RNA splicing and metabolism. In disease, however, they are typically mislocalized to the cytoplasm where they form aggregated inclusions. A number of shared cellular pathways have been identified that contribute to TDP-43 and FUS toxicity in neurodegeneration. In the present study, we report a novel pathogenic mechanism shared by these two proteins. We found that pathological FUS co-aggregates with a ribosomal protein, the Receptor for Activated C-Kinase 1 (RACK1), in the cytoplasm of spinal cord motor neurons of ALS, as previously reported for pathological TDP-43. In HEK293T cells transiently transfected with TDP-43 or FUS mutant lacking a functional nuclear localization signal (NLS; TDP-43ΔNLS and FUSΔNLS), cytoplasmic TDP-43 and FUS induced co-aggregation with endogenous RACK1. These co-aggregates sequestered the translational machinery through interaction with the polyribosome, accompanied by a significant reduction of global protein translation. RACK1 knockdown decreased cytoplasmic aggregation of TDP-43ΔNLS or FUSΔNLS and alleviated associated global translational suppression. Surprisingly, RACK1 knockdown also led to partial nuclear localization of TDP-43ΔNLS and FUSΔNLS in some transfected cells, despite the absence of NLS. In vivo, RACK1 knockdown alleviated retinal neuronal degeneration in transgenic Drosophila melanogaster expressing hTDP-43WT or hTDP-43Q331K and improved motor function of hTDP-43WT flies, with no observed adverse effects on neuronal health in control knockdown flies. In conclusion, our results revealed a novel shared mechanism of pathogenesis for misfolded aggregates of TDP-43 and FUS mediated by interference with protein translation in a RACK1-dependent manner. We provide proof-of-concept evidence for targeting RACK1 as a potential therapeutic approach for TDP-43 or FUS proteinopathy associated with ALS and FTLD.
Assuntos
Esclerose Lateral Amiotrófica , Demência Frontotemporal , Degeneração Lobar Frontotemporal , Sarcoma , Animais , Humanos , Esclerose Lateral Amiotrófica/patologia , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Células HEK293 , Neurônios Motores/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Demência Frontotemporal/patologia , Degeneração Lobar Frontotemporal/patologia , Biossíntese de Proteínas , Sarcoma/metabolismo , Sarcoma/patologia , Proteína FUS de Ligação a RNA/genética , Proteína FUS de Ligação a RNA/metabolismo , Receptores de Quinase C Ativada/genética , Receptores de Quinase C Ativada/metabolismo , Proteínas de Neoplasias/genéticaRESUMO
The receptor for activated C kinase 1 (RACK1) is a key scaffolding protein with multifunctional and multifaceted properties. By mediating protein-protein interactions, RACK1 integrates multiple intracellular signals involved in the regulation of various physiological and pathological processes. Dysregulation of RACK1 has been implicated in the initiation and progression of many tumors. However, the exact function of RACK1 in cancer cellular processes, especially in proliferation, remains controversial. Here, we show that RACK1 is required for breast cancer cell proliferation in vitro and tumor growth in vivo. This effect of RACK1 is associated with its ability to enhance ß-catenin stability and activate the canonical WNT signaling pathway in breast cancer cells. We identified PSMD2, a key component of the proteasome, as a novel binding partner for RACK1 and ß-catenin. Interestingly, although there is no interaction between RACK1 and ß-catenin, RACK1 binds PSMD2 competitively with ß-catenin. Moreover, RACK1 prevents ubiquitinated ß-catenin from binding to PSMD2, thereby protecting ß-catenin from proteasomal degradation. Collectively, our findings uncover a novel mechanism by which RACK1 increases ß-catenin stability and promotes breast cancer proliferation.
Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/patologia , beta Catenina/metabolismo , Via de Sinalização Wnt/fisiologia , Proliferação de Células , Linhagem Celular Tumoral , Fator 2 Associado a Receptor de TNF/metabolismo , Receptores de Quinase C Ativada/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismoRESUMO
Receptor for activated C kinase 1 (RACK1) has been confirmed to take part in multiple biological events and the mechanism supporting abnormal RACK1 expression in ovarian cancer (OC) remains to be characterized. Here, we identified Smad ubiquitin regulatory factor 2 (SMURF2) as a bona fide E3 ligase of RACK1 in OC. SMURF2 effectively added the K6, K33 and K48 ubiquitin chains to the RACK1, resulting in polyubiquitination and instability of RACK1. PCAF promoted acetylation of RACK1 at K130, leading to SMURF2-mediated RACK1 ubiquitination inhibited and promote OC progression. The expression levels of SMURF2 and RACK1 were negatively correlated. SMURF2 was abnormal low expression in human ovarian cancer, resulting in decreased ubiquitination of RACK1 and increased stability, which promoted OC progression, and strongly associated with poor patients' prognosis. In general, our results demonstrated that SMURF2 plays a pivotal role in stabilizing RACK1, which in turn facilitates tumorigenesis in OC, suggesting that SMURF2-RACK1 axis may prove to be potential targets for the treatment of OC.
Assuntos
Neoplasias Ovarianas , Ubiquitina , Feminino , Humanos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Processamento de Proteína Pós-Traducional , Receptores de Quinase C Ativada/genética , Receptores de Quinase C Ativada/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
Neuropilin 1 (NRP1) is a single-channel transmembrane glycoprotein whose role and mechanism in renal fibrosis remain incompletely elucidated. Therefore, we investigated the effect of NRP1 on renal fibrosis and its potential mechanism. NRP1 expression in the renal sections from patients with chronic kidney disease (CKD) and a unilateral ureteral obstruction (UUO) mouse model was detected. Nrp1 overexpression or knockdown plasmid was transfected into mice, TKPTS mouse kidney proximal tubular epithelial cells (TECs), and rat kidney fibroblasts, after which pathological injury evaluation and fibrosis marker detection were conducted. The direct interaction of the receptor of activated protein C kinase 1 (RACK1) with NRP1 was validated by immunoprecipitation and Western blot analysis. We found that the upregulated renal NRP1 expression in patients with CKD was located in proximal TECs, consistent with the degree of interstitial fibrosis. In the UUO mouse model, NRP1 expression was upregulated in the kidney, and overexpression of Nrp1 increased the mRNA and protein expression of fibronectin (Fn) and α-smooth muscle actin (α-SMA), whereas Nrp1 knockdown significantly reduced Fn and α-SMA expression and downregulated the inflammatory response. NRP1 promoted transforming growth factor ß1 (TGF-ß1)-induced profibrotic responses in the TKPTS cells and fibroblasts, and Nrp1 knockdown partially reversed these responses. Immunoprecipitation combined with liquid chromatography-tandem mass spectrometry verified that NRP1 can directly bind to RACK1, and Rack1 knockdown reversed the NRP1-induced fibrotic response. In summary, NRP1 may enhance the TGF-ß1 pathway by binding to RACK1, thus promoting renal fibrosis.NEW & NOTEWORTHY Although a few studies have confirmed the correlation between neuropilin 1 (NRP1) and renal diseases, the mechanism of NRP1 in renal fibrosis remains unclear. Here, we investigated the effects of NRP1 on renal fibrosis through in vitro and in vivo experiments and explored the possible downstream mechanisms. We found that NRP1 can stimulate the TGF-ß1 signaling pathway, possibly by binding to RACK1, thereby promoting renal fibrosis.
Assuntos
Nefropatias , Neuropilina-1 , Receptores de Quinase C Ativada , Insuficiência Renal Crônica , Obstrução Ureteral , Animais , Humanos , Camundongos , Ratos , Células Epiteliais/metabolismo , Fibrose , Rim/metabolismo , Nefropatias/patologia , Proteínas de Neoplasias/metabolismo , Neuropilina-1/genética , Neuropilina-1/metabolismo , Receptores de Quinase C Ativada/genética , Receptores de Quinase C Ativada/metabolismo , Insuficiência Renal Crônica/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Obstrução Ureteral/patologiaRESUMO
Fragile X messenger ribonucleoprotein 1 protein (FMRP) deficiency leads to fragile X syndrome (FXS), an autism spectrum disorder. The role of FMRP in prenatal human brain development remains unclear. Here, we show that FMRP is important for human and macaque prenatal brain development. Both FMRP-deficient neurons in human fetal cortical slices and FXS patient stem cell-derived neurons exhibit mitochondrial dysfunctions and hyperexcitability. Using multiomics analyses, we have identified both FMRP-bound mRNAs and FMRP-interacting proteins in human neurons and unveiled a previously unknown role of FMRP in regulating essential genes during human prenatal development. We demonstrate that FMRP interaction with CNOT1 maintains the levels of receptor for activated C kinase 1 (RACK1), a species-specific FMRP target. Genetic reduction of RACK1 leads to both mitochondrial dysfunctions and hyperexcitability, resembling FXS neurons. Finally, enhancing mitochondrial functions rescues deficits of FMRP-deficient cortical neurons during prenatal development, demonstrating targeting mitochondrial dysfunction as a potential treatment.