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1.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 40(6): 481-487, 2024 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-38952086

RESUMO

Objective To elucidate the role of chaperone-mediated autophagy (CMA) in alleviating emotional dysfunction in mice with sepsis-associated encephalopathy (SAE). Methods The SAE mouse model was established by cecal ligation and perforation (CLP). The severity of sepsis was assessed using the sepsis severity score (MSS). Emotional function in SAE mice was assessed by the open-field test and elevated plus-maze. The expression levels of cognitive heat shock cognate protein 70 (HSC70), lysosomal-associated membrane protein 2A (LAMP2A) and high mobility group box 1 protein B1 (HMGB1) were detected using Western blotting. Co-localization of LAMP2A in the hippocampal neurons was observed by immunofluorescence. The release of inflammatory factors interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) was measured using ELISA. Following 12 hours post-CLP, mice were orally administered resveratrol at a dose of 30 mg/kg once daily until day 14. Results The mortality rate of CLP mice was 45.83% 24 days post CLP, and all surviving mice exhibited emotional disturbances. 24 hours after CLP, a significant decrease in HSC70 and LAMP2A expression in hippocampal neurons was observed, indicating impaired CMA activity. Meanwhile, HMGB1 and inflammatory cytokines (IL-6 and TNF-α) levels increased. After resveratrol treatment, an increase of HSC70 and LAMP2A expression, and a decrease of HMGB1 expression and inflammatory cytokine release were observed, suggesting enhanced CMA activity and reduced neuroinflammation. Behavioral tests showed that emotional dysfunction was improved in SAE mice after resveratrol treatment. Conclusion CMA activity of hippocampal neurons in SAE mice is significantly reduced, leading to emotional dysfunction. Resveratrol can alleviate neuroinflammation and emotional dysfunction in SAE mice by promoting CMA and inhibiting the expression of HMGB1 and the release of inflammatory factors.


Assuntos
Autofagia Mediada por Chaperonas , Proteína HMGB1 , Resveratrol , Encefalopatia Associada a Sepse , Animais , Camundongos , Encefalopatia Associada a Sepse/tratamento farmacológico , Encefalopatia Associada a Sepse/fisiopatologia , Encefalopatia Associada a Sepse/metabolismo , Masculino , Resveratrol/farmacologia , Proteína HMGB1/metabolismo , Autofagia Mediada por Chaperonas/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/genética , Doenças Neuroinflamatórias/tratamento farmacológico , Doenças Neuroinflamatórias/etiologia , Doenças Neuroinflamatórias/metabolismo , Hipocampo/metabolismo , Hipocampo/efeitos dos fármacos , Interleucina-6/metabolismo , Estilbenos/farmacologia , Proteínas de Choque Térmico HSC70/metabolismo , Sepse/complicações , Sepse/tratamento farmacológico , Sepse/metabolismo , Sepse/fisiopatologia , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças
2.
Proc Natl Acad Sci U S A ; 121(26): e2317945121, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38889154

RESUMO

Chaperone-mediated autophagy (CMA) is part of the mammalian cellular proteostasis network that ensures protein quality control, maintenance of proteome homeostasis, and proteome changes required for the adaptation to stress. Loss of proteostasis is one of the hallmarks of aging. CMA decreases with age in multiple rodent tissues and human cell types. A decrease in lysosomal levels of the lysosome-associated membrane protein type 2A (LAMP2A), the CMA receptor, has been identified as a main reason for declined CMA in aging. Here, we report constitutive activation of CMA with calorie restriction (CR), an intervention that extends healthspan, in old rodent livers and in an in vitro model of CR with cultured fibroblasts. We found that CR-mediated upregulation of CMA is due to improved stability of LAMP2A at the lysosome membrane. We also explore the translational value of our observations using calorie-restriction mimetics (CRMs), pharmacologically active substances that reproduce the biochemical and functional effects of CR. We show that acute treatment of old mice with CRMs also robustly activates CMA in several tissues and that this activation is required for the higher resistance to lipid dietary challenges conferred by treatment with CRMs. We conclude that part of the beneficial effects associated with CR/CRMs could be a consequence of the constitutive activation of CMA mediated by these interventions.


Assuntos
Restrição Calórica , Autofagia Mediada por Chaperonas , Proteína 2 de Membrana Associada ao Lisossomo , Lisossomos , Animais , Camundongos , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/genética , Lisossomos/metabolismo , Humanos , Envelhecimento/metabolismo , Fibroblastos/metabolismo , Proteostase , Fígado/metabolismo , Camundongos Endogâmicos C57BL , Masculino , Autofagia
3.
Neuroreport ; 35(12): 771-779, 2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-38935077

RESUMO

Recent studies have shown that autophagy is activated in response to nerve damage and occurs simultaneously with the initial stages of Schwann cell-mediated demyelination. Although several studies have reported that macroautophagy is involved in the peripheral nerve, the role of chaperone-mediated autophagy (CMA) has not yet been investigated in peripheral nerve injury. The present study investigates the role of CMA in the sciatic nerve. Using a mouse model of sciatic nerve injury, the authors employed immunofluorescence analysis to observe the expression of LAMP2A, a critical marker for CMA. RNA sequencing was performed to observe the transcriptional profile of Lamp2a in Schwann cells. Bioinformatics analysis was carried out to observe the hub genes associated with Lamp2a . Expression of Lamp2a , a key gene in CMA, increased following sciatic nerve injury, based on an immunofluorescence assay. To identify differentially expressed genes using Lamp2a , RNA sequence analysis was conducted using rat Schwann cells overexpressing Lamp2a . The nine hub genes ( Snrpf, Polr1d, Snip1, Aqr, Polr2h, Ssbp1, Mterf3, Adcy6 , and Sbds ) were identified using the CytoHubba plugin of Cytoscape. Functional analysis revealed that Lamp2a overexpression affected the transcription levels of genes associated with mitotic spindle organization and mRNA splicing via the spliceosome. In addition, Polr1d and Snrpf1 were downregulated throughout postnatal development but elevated following sciatic nerve injury, according to a bioinformatics study. CMA may be an integral pathway in sciatic nerve injury via mRNA splicing.


Assuntos
Biologia Computacional , Proteína 2 de Membrana Associada ao Lisossomo , Células de Schwann , Nervo Isquiático , Animais , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/genética , Camundongos , Células de Schwann/metabolismo , Nervo Isquiático/lesões , Nervo Isquiático/metabolismo , Traumatismos dos Nervos Periféricos/genética , Traumatismos dos Nervos Periféricos/metabolismo , Ratos , Masculino , Autofagia Mediada por Chaperonas/genética , Camundongos Endogâmicos C57BL , Neuropatia Ciática/genética , Neuropatia Ciática/metabolismo
4.
Aging (Albany NY) ; 16(10): 9072-9105, 2024 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-38787367

RESUMO

Alzheimer's disease (AD) is a progressive brain disorder marked by abnormal protein accumulation and resulting proteotoxicity. This study examines Chaperone-Mediated Autophagy (CMA), particularly substrate translocation into lysosomes, in AD. The study observes: (1) Increased substrate translocation activity into lysosomes, vital for CMA, aligns with AD progression, highlighted by gene upregulation and more efficient substrate delivery. (2) This CMA phase strongly correlates with AD's clinical symptoms; more proteotoxicity links to worse dementia, underscoring the need for active degradation. (3) Proteins like GFAP and LAMP2A, when upregulated, almost certainly indicate AD risk, marking this process as a significant AD biomarker. Based on these observations, this study proposes the following hypothesis: As AD progresses, the aggregation of pathogenic proteins increases, the process of substrate entry into lysosomes via CMA becomes active. The genes associated with this process exhibit heightened sensitivity to AD. This conclusion stems from an analysis of over 10,000 genes and 363 patients using two AI methodologies. These methodologies were instrumental in identifying genes highly sensitive to AD and in mapping the molecular networks that respond to the disease, thereby highlighting the significance of this critical phase of CMA.


Assuntos
Doença de Alzheimer , Autofagia Mediada por Chaperonas , Progressão da Doença , Proteína 2 de Membrana Associada ao Lisossomo , Lisossomos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Humanos , Autofagia Mediada por Chaperonas/genética , Lisossomos/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/genética , Idoso , Feminino , Masculino , Transporte Proteico , Proteína Glial Fibrilar Ácida
5.
FASEB J ; 38(10): e23646, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38795328

RESUMO

Multiple regulatory mechanisms are in place to ensure the normal processes of bone metabolism, encompassing both bone formation and absorption. This study has identified chaperone-mediated autophagy (CMA) as a critical regulator that safeguards bone formation from the detrimental effects of excessive inflammation. By silencing LAMP2A or HSCA8, we observed a hindrance in the osteoblast differentiation of human bone marrow mesenchymal stem cells (hBMSCs) in vitro. To further elucidate the role of LAMP2A, we generated LAMP2A gene knockdown and overexpression of mouse BMSCs (mBMSCs) using adenovirus. Our results showed that LAMP2A knockdown led to a decrease in osteogenic-specific proteins, while LAMP2A overexpression favored the osteogenesis of mBMSCs. Notably, active-ß-catenin levels were upregulated by LAMP2A overexpression. Furthermore, we found that LAMP2A overexpression effectively protected the osteogenesis of mBMSCs from TNF-α, through the PI3K/AKT/GSK3ß/ß-catenin pathway. Additionally, LAMP2A overexpression significantly inhibited osteoclast hyperactivity induced by TNF-α. Finally, in a murine bone defect model, we demonstrated that controlled release of LAMP2A overexpression adenovirus by alginate sodium capsule efficiently protected bone healing from inflammation, as confirmed by imaging and histological analyses. Collectively, our findings suggest that enhancing CMA has the potential to safeguard bone formation while mitigating hyperactivity in bone absorption.


Assuntos
Autofagia Mediada por Chaperonas , Glicogênio Sintase Quinase 3 beta , Inflamação , Proteína 2 de Membrana Associada ao Lisossomo , Células-Tronco Mesenquimais , Osteogênese , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , beta Catenina , Animais , Osteogênese/fisiologia , Glicogênio Sintase Quinase 3 beta/metabolismo , Glicogênio Sintase Quinase 3 beta/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , beta Catenina/metabolismo , Humanos , Células-Tronco Mesenquimais/metabolismo , Inflamação/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/genética , Transdução de Sinais , Masculino , Camundongos Endogâmicos C57BL , Osteoblastos/metabolismo , Diferenciação Celular , Osteoclastos/metabolismo
6.
PLoS Pathog ; 20(4): e1012123, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38607975

RESUMO

RAB GTPases (RABs) control intracellular membrane trafficking with high precision. In the present study, we carried out a short hairpin RNA (shRNA) screen focused on a library of 62 RABs during infection with porcine reproductive and respiratory syndrome virus 2 (PRRSV-2), a member of the family Arteriviridae. We found that 13 RABs negatively affect the yield of PRRSV-2 progeny virus, whereas 29 RABs have a positive impact on the yield of PRRSV-2 progeny virus. Further analysis revealed that PRRSV-2 infection transcriptionally regulated RAB18 through RIG-I/MAVS-mediated canonical NF-κB activation. Disrupting RAB18 expression led to the accumulation of lipid droplets (LDs), impaired LDs catabolism, and flawed viral replication and assembly. We also discovered that PRRSV-2 co-opts chaperone-mediated autophagy (CMA) for lipolysis via RAB18, as indicated by the enhanced associations between RAB18 and perlipin 2 (PLIN2), CMA-specific lysosomal associated membrane protein 2A (LAMP2A), and heat shock protein family A (Hsp70) member 8 (HSPA8/HSC70) during PRRSV-2 infection. Knockdown of HSPA8 and LAMP2A impacted on the yield of PRRSV-2 progeny virus, implying that the virus utilizes RAB18 to promote CMA-mediated lipolysis. Importantly, we determined that the C-terminal domain (CTD) of HSPA8 could bind to the switch II domain of RAB18, and the CTD of PLIN2 was capable of associating with HSPA8, suggesting that HSPA8 facilitates the interaction between RAB18 and PLIN2 in the CMA process. In summary, our findings elucidate how PRRSV-2 hijacks CMA-mediated lipid metabolism through innate immune activation to enhance the yield of progeny virus, offering novel insights for the development of anti-PRRSV-2 treatments.


Assuntos
Autofagia Mediada por Chaperonas , Vírus da Síndrome Respiratória e Reprodutiva Suína , Suínos , Animais , Lipólise , Regulação para Cima , Proteínas rab de Ligação ao GTP/genética , Proteínas de Membrana Lisossomal , RNA Interferente Pequeno
7.
Zhongguo Dang Dai Er Ke Za Zhi ; 26(4): 385-393, 2024 Apr 15.
Artigo em Chinês | MEDLINE | ID: mdl-38660903

RESUMO

OBJECTIVES: To investigate the effect of chaperone-mediated autophagy (CMA) on the damage of mouse microglial BV2 cells induce by unconjugated bilirubin (UCB). METHODS: The BV2 cell experiments were divided into two parts. (1) For the CMA activation experiment: control group (treated with an equal volume of dimethyl sulfoxide), QX77 group (treated with 20 µmol/L QX77 for 24 hours), UCB group (treated with 40 µmol/L UCB for 24 hours), and UCB+QX77 group (treated with both 20 µmol/L QX77 and 40 µmol/L UCB for 24 hours). (2) For the cell transfection experiment: LAMP2A silencing control group (treated with an equal volume of dimethyl sulfoxide), LAMP2A silencing control+UCB group (treated with 40 µmol/L UCB for 24 hours), LAMP2A silencing group (treated with an equal volume of dimethyl sulfoxide), and LAMP2A silencing+UCB group (treated with 40 µmol/L UCB for 24 hours). The cell viability was assessed using the modified MTT method. The expression levels of p65, nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), and cysteinyl aspartate specific proteinase-1 (caspase-1) were detected by Western blot. The relative mRNA expression levels of the inflammatory cytokines interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α) were determined by real-time quantitative polymerase chain reaction. Levels of IL-6 and TNF-α in the cell culture supernatant were measured using ELISA. The co-localization of heat shock cognate protein 70 with p65 and NLRP3 was detected by immunofluorescence. RESULTS: Compared to the UCB group, the cell viability in the UCB+QX77 group increased, and the expression levels of inflammation-related proteins p65, NLRP3, and caspase-1, as well as the mRNA relative expression levels of IL-1ß, IL-6, and TNF-α and levels of IL-6 and TNF-α decreased (P<0.05). Compared to the control group, there was co-localization of heat shock cognate protein 70 with p65 and NLRP3 in both the UCB and UCB+QX77 groups. After silencing the LAMP2A gene, compared to the LAMP2A silencing control+UCB group, the LAMP2A silencing+UCB group showed increased expression levels of inflammation-related proteins p65, NLRP3, and caspase-1, as well as increased mRNA relative expression levels of IL-1ß, IL-6, and TNF-α and levels of IL-6 and TNF-α (P<0.05). CONCLUSIONS: CMA is inhibited in UCB-induced BV2 cell damage, and activating CMA may reduce p65 and NLRP3 protein levels, suppress inflammatory responses, and counteract bilirubin neurotoxicity.


Assuntos
Bilirrubina , Autofagia Mediada por Chaperonas , Microglia , Animais , Camundongos , Microglia/metabolismo , Autofagia Mediada por Chaperonas/fisiologia , Autofagia Mediada por Chaperonas/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/fisiologia , Proteína 2 de Membrana Associada ao Lisossomo/genética , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Caspase 1/genética , Caspase 1/metabolismo , Fator de Transcrição RelA/metabolismo , Fator de Transcrição RelA/genética , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/genética , Interleucina-1beta/metabolismo , Interleucina-1beta/genética , Interleucina-6/metabolismo , Interleucina-6/genética , Células Cultivadas , Sobrevivência Celular
8.
Pharmacology ; 109(4): 216-230, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38569476

RESUMO

INTRODUCTION: Acute myeloid leukemia (AML) is a cancer of the hematopoietic system characterized by hyperproliferation of undifferentiated cells of the myeloid lineage. While most of AML therapies are focused toward tumor debulking, all-trans retinoic acid (ATRA) induces neutrophil differentiation in the AML subtype acute promyelocytic leukemia (APL). Macroautophagy has been extensively investigated in the context of various cancers and is often dysregulated in AML where it can have context-dependent pro- or anti-leukemogenic effects. On the contrary, the implications of chaperone-mediated autophagy (CMA) on the pathophysiology of diseases are still being explored and its role in AML remains elusive. METHODS: We took advantage of human AML primary samples and databases to analyze CMA gene expression and activity. Furthermore, we used ATRA-sensitive (NB4) and -resistant (NB4-R1) APL cells to further dissect a potential function for CMA in ATRA-mediated neutrophil differentiation. NB4-R1 cells are unique in that they do respond to retinoic acid transcriptionally but do not mature in response to retinoid signaling alone unless maturation is triggered by adding cyclic adenosine monophosphate. RESULTS: Here, we report that CMA-related mRNA transcripts are significantly higher expressed in immature hematopoietic cells as compared to neutrophils, contrasting the macroautophagy gene expression patterns. Accordingly, lysosomal degradation of an mCherry-KFERQ CMA reporter decreases during ATRA-induced differentiation of APL cells. On the other hand, using NB4-R1 cells we found that macroautophagy flux primed ATRA-resistant NB4-R1 cells to differentiate upon ATRA treatment but reduced the association of lysosome-associated membrane protein type 2A (LAMP-2A) and heat shock protein family A (Hsp70) member 8 (HSPA8), necessary for complete neutrophil maturation. Accordingly, depletion of HSPA8 attenuated CMA activity and facilitated APL cell differentiation. In contrast, maintaining high CMA activity by ectopic expression of LAMP-2A impeded APL differentiation. CONCLUSION: Overall, our findings suggest that APL neutrophil differentiation requires CMA inactivation and that this pathway predominantly depends on HSPA8 and is possibly assisted by other co-chaperones.


Assuntos
Diferenciação Celular , Autofagia Mediada por Chaperonas , Proteínas de Choque Térmico HSC70 , Leucemia Promielocítica Aguda , Tretinoína , Humanos , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Leucemia Promielocítica Aguda/tratamento farmacológico , Diferenciação Celular/efeitos dos fármacos , Tretinoína/farmacologia , Autofagia Mediada por Chaperonas/efeitos dos fármacos , Linhagem Celular Tumoral , Proteínas de Choque Térmico HSC70/metabolismo , Proteínas de Choque Térmico HSC70/genética , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Antineoplásicos/farmacologia
9.
Sci Total Environ ; 927: 172069, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38582117

RESUMO

Ferroptosis is a newly recognized type of programmed cell death that is implicated in the pathophysiological process of neurological disorders. Our previous studies have revealed that exposure to high concentrations of fluoride for long periods of time induces hippocampal neural injury and cognitive deficits. However, whether ferroptosis is involved in fluoride-induced neuronal death and the underlying mechanism remain unknown. In this study, the results indicated that exposure to high fluoride triggered ferroptosis in SH-SY5Y cells and in the hippocampus of mice. Fluoride exposure accelerated the lysosomal degradation of GPX4 and led to neuronal ferroptosis, while GPX4 overexpression protected SH-SY5Y cells against fluoride-induced neurotoxicity. Intriguingly, the enhanced chaperone-mediated autophagy (CMA) induced by fluoride stimulation was responsible for GPX4 degradation because the inhibition of CMA activity by LAMP2A knockdown effectively prevented fluoride-induced GPX4 loss. Furthermore, mitochondrial ROS (mtROS) accumulation caused by fluoride contributed to CMA activation-mediated GPX4 degradation and subsequent neuronal ferroptosis. Notably, the ferroptosis-specific inhibitor ferrostatin-1 (Fer-1) or the ROS scavenger N-acetyl-L-cysteine (NAC) alleviated fluoride-evoked hippocampal neuronal death and synaptic injury as well as cognitive deficits in mice. The present studies indicates that ferroptosis is a novel mechanism of fluoride-induced neurotoxicity and that chronic fluoride exposure facilitates GPX4 degradation via mtROS chaperone-mediated autophagy, leading to neuronal ferroptosis and cognitive impairment.


Assuntos
Autofagia Mediada por Chaperonas , Disfunção Cognitiva , Ferroptose , Fluoretos , Neurônios , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Espécies Reativas de Oxigênio , Animais , Humanos , Camundongos , Autofagia/efeitos dos fármacos , Autofagia Mediada por Chaperonas/fisiologia , Autofagia Mediada por Chaperonas/efeitos dos fármacos , Disfunção Cognitiva/induzido quimicamente , Ferroptose/efeitos dos fármacos , Ferroptose/fisiologia , Fluoretos/toxicidade , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Neurônios/efeitos dos fármacos , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/efeitos dos fármacos , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo , Espécies Reativas de Oxigênio/metabolismo
10.
Lipids Health Dis ; 23(1): 91, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38539242

RESUMO

BACKGROUND: ß-Propeller protein-associated neurodegeneration (BPAN) is a genetic neurodegenerative disease caused by mutations in WDR45. The impairment of autophagy caused by WDR45 deficiency contributes to the pathogenesis of BPAN; however, the pathomechanism of this disease is largely unknown. Lipid dyshomeostasis is involved in neurogenerative diseases, but whether lipid metabolism is affected by Wdr45 deficiency and whether lipid dyshomeostasis contributes to the progression of BPAN are unclear. METHODS: We generated Wdr45 knockout SN4741 cell lines using CRISPR‒Cas9-mediated genome editing, then lipid droplets (LDs) were stained using BODIPY 493/503. Chaperone-mediated autophagy was determined by RT-qPCR and western blotting. The expression of fatty acid synthase (Fasn) was detected by western blot in the presence or absence of the lysosomal inhibitor NH4Cl and the CMA activator AR7. The interaction between Fasn and HSC70 was analyzed using coimmunoprecipitation (Co-IP) assay. Cell viability was measured by a CCK-8 kit after treatment with the Fasn inhibitor C75 or the CMA activator AR7. RESULTS: Deletion of Wdr45 impaired chaperone-mediated autophagy (CMA), thus leading to lipid droplet (LD) accumulation. Moreover, Fasn can be degraded via CMA, and that defective CMA leads to elevated Fasn, which promotes LD formation. LD accumulation is toxic to cells; however, cell viability was not rescued by Fasn inhibition or CMA activation. Inhibition of Fasn with a low concentration of C75 did not affect cell viability but decreases LD density. CONCLUSIONS: These results suggested that Fasn is essential for cell survival but that excessive Fasn leads to LD accumulation in Wdr45 knockout cells.


Assuntos
Autofagia Mediada por Chaperonas , Doenças Neurodegenerativas , Humanos , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Gotículas Lipídicas/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Autofagia/genética , Ácido Graxo Sintases/metabolismo , Lipídeos
11.
Angew Chem Int Ed Engl ; 63(18): e202319232, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38472118

RESUMO

Cell-surface proteins are important drug targets but historically have posed big challenges for the complete elimination of their functions. Herein, we report antibody-peptide conjugates (Ab-CMAs) in which a peptide targeting chaperone-mediated autophagy (CMA) was conjugated with commercially available monoclonal antibodies for specific cell-surface protein degradation by taking advantage of lysosomal degradation pathways. Unique features of Ab-CMAs, including cell-surface receptor- and E3 ligase-independent degradation, feasibility towards different cell-surface proteins (e.g., epidermal growth factor receptor (EGFR), programmed cell death ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2)) by a simple change of the antibody, and successful tumor inhibition in vivo, make them attractive protein degraders for biomedical research and therapeutic applications. As the first example employing CMA to degrade proteins from the outside in, our findings may also shed new light on CMA, a degradation pathway typically targeting cytosolic proteins.


Assuntos
Autofagia Mediada por Chaperonas , Neoplasias , Humanos , Autofagia/fisiologia , Proteínas de Membrana/metabolismo , Neoplasias/metabolismo , Peptídeos/metabolismo , Lisossomos/metabolismo
12.
Curr Protoc ; 4(1): e950, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38197533

RESUMO

Chaperone-mediated autophagy (CMA) is the most selective form of lysosomal proteolysis, in which proteins are individually selected for lysosomal degradation. CMA degradation targets bear a pentapeptide consensus motif that is recognized by the cytosolic chaperone HSPA8 (Hsc70), which participates in the trafficking of the target to the lysosomal surface. From there, it is translocated into the lysosomal lumen, independent of vesicle fusion, in a process dependent upon the lysosomal transmembrane protein LAMP2A. There are limited tools for studying CMA in whole cells and tissues, and many of the best techniques for studying CMA rely on the preparation of lysosome enriched fractions. Such experiments include (1) the in vitro evaluation of CMA substrate uptake activity, (2) the characterization of changes to lysosomal resident and CMA regulatory proteins, and (3) lysosomal targetomics, i.e., the use of quantitative proteomics to characterize lysosomal degradation targets. Previous studies using discontinuous metrizamide gradients have shown that a subpopulation of liver lysosomes is responsible for the majority of CMA activity ("CMA+ "). These CMA+ lysosomes are low density and have higher levels of MTORC2 relative to the "CMA- " lysosomes, which are high density and have higher levels of MTORC1. Because of safety concerns surrounding metrizamide, however, this compound is difficult to obtain, and it is impractically expensive. Here, we have provided protocols for isolation of lysosomal subpopulations for CMA-related analyses from mouse liver using Histodenz, a safe and affordable alternative to metrizamide. Supplementary protocols show how to perform CMA activity assays with appropriate statistical analysis, and how to analyze for lysosomal breakage/membrane integrity. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Isolation of lysosomal subpopulations from mouse liver using discontinuous Histodenz gradients Alternate Protocol: Isolation of lysosomes from cultured cells using discontinuous Histodenz gradients Support Protocol 1: Verifying enrichment of lysosomal markers in lysosome-enriched fractions Support Protocol 2: Measuring in vitro uptake of CMA substrates Support Protocol 3: Measuring lysosomal membrane integrity by hexosaminidase assay.


Assuntos
Autofagia Mediada por Chaperonas , Animais , Camundongos , Metrizamida , Lisossomos , beta-N-Acetil-Hexosaminidases , Bioensaio
13.
Drug Resist Updat ; 73: 101037, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38171078

RESUMO

Chaperone-mediated autophagy (CMA), a proteolytic system contributing to the degradation of intracellular proteins in lysosomes, is upregulated in tumors for pro-tumorigenic and pro-survival purposes. In this study, bioinformatics analysis revealed the co-occurrence of upregulated CMA and PD-L1 accumulation in metastatic melanoma with adaptive immune resistance (AIR) to anti-PD1 treatment, suggesting the potential therapeutic effects of rewiring CMA for PD-L1 degradation. Furthermore, this co-occurrence is attributed to IFN-γ-mediated compensatory up-regulation of PD-L1 and CMA, accompanied by enhanced macropinocytosis. Drawing inspiration from the cellular uptake of prions via macropinocytosis, a prion-like chemical inducer of proximity called SAP was engineered using self-assembly of the designed chiral peptide PHA. By exploiting sensitized macropinocytosis, SAP clandestinely infiltrates tumor cells and subsequently disintegrates into PHA, which reprograms CMA by inducing PD-L1 close to HSPA8. SAP degrades PD-L1 in a CMA-dependent manner and effectively restores the anti-tumor immune response in both allografting and Hu-PDX melanoma mouse models with AIR while upholding a high safety profile. Collectively, the reported SAP not only presents an immune reactivation strategy with clinical translational potential for overcoming AIR in cutaneous melanomas but serves as a reproducible example of precision-medicine-guided drug development that fully leverages specific cellular indications in pathological states.


Assuntos
Autofagia Mediada por Chaperonas , Melanoma , Príons , Camundongos , Animais , Antígeno B7-H1/metabolismo , Melanoma/metabolismo , Príons/metabolismo , Lisossomos/metabolismo
14.
Basic Res Cardiol ; 119(1): 113-131, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38168863

RESUMO

Calcium overload is the key trigger in cardiac microvascular ischemia-reperfusion (I/R) injury, and calreticulin (CRT) is a calcium buffering protein located in the endoplasmic reticulum (ER). Additionally, the role of pinacidil, an antihypertensive drug, in protecting cardiac microcirculation against I/R injury has not been investigated. Hence, this study aimed to explore the benefits of pinacidil on cardiac microvascular I/R injury with a focus on endothelial calcium homeostasis and CRT signaling. Cardiac vascular perfusion and no-reflow area were assessed using FITC-lectin perfusion assay and Thioflavin-S staining. Endothelial calcium homeostasis, CRT-IP3Rs-MCU signaling expression, and apoptosis were assessed by real-time calcium signal reporter GCaMP8, western blotting, and fluorescence staining. Drug affinity-responsive target stability (DARTS) assay was adopted to detect proteins that directly bind to pinacidil. The present study found pinacidil treatment improved capillary density and perfusion, reduced no-reflow and infraction areas, and improved cardiac function and hemodynamics after I/R injury. These benefits were attributed to the ability of pinacidil to alleviate calcium overload and mitochondria-dependent apoptosis in cardiac microvascular endothelial cells (CMECs). Moreover, the DARTS assay showed that pinacidil directly binds to HSP90, through which it inhibits chaperone-mediated autophagy (CMA) degradation of CRT. CRT overexpression inhibited IP3Rs and MCU expression, reduced mitochondrial calcium inflow and mitochondrial injury, and suppressed endothelial apoptosis. Importantly, endothelial-specific overexpression of CRT shared similar benefits with pinacidil on cardiovascular protection against I/R injury. In conclusion, our data indicate that pinacidil attenuated microvascular I/R injury potentially through improving CRT degradation and endothelial calcium overload.


Assuntos
Autofagia Mediada por Chaperonas , Traumatismo por Reperfusão , Humanos , Pinacidil/metabolismo , Células Endoteliais/metabolismo , Calreticulina/metabolismo , Cálcio/metabolismo , Traumatismo por Reperfusão/metabolismo , Apoptose
15.
Autophagy ; 20(1): 216-217, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37669771

RESUMO

PTEN is a negative modulator of the INS-PI3K-AKT pathway and is an essential regulator of metabolism and cell growth. PTEN is one of the most commonly mutated tumor suppressors in cancer. However, PTEN overexpression extends the lifespan of both sexes of mice. We recently showed that PTEN is necessary and sufficient to activate chaperone-mediated autophagy (CMA) in the mouse liver and cultured cells. Selective protein degradation via CMA is required to suppress glycolysis and fatty acid synthesis when PTEN is overexpressed. Thus, activation of CMA downstream of PTEN might modulate health and metabolism through selective degradation of key metabolic enzymes.


Assuntos
Autofagia Mediada por Chaperonas , PTEN Fosfo-Hidrolase , Animais , Camundongos , PTEN Fosfo-Hidrolase/metabolismo , Células NIH 3T3 , Transdução de Sinais , Fígado/metabolismo , Glicólise , Ácidos Graxos/biossíntese , Masculino , Feminino , Lisossomos/metabolismo
16.
J Nippon Med Sch ; 91(1): 2-9, 2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-37271546

RESUMO

Autophagy is a self-digestive process that is conserved in eukaryotic cells and responsible for maintaining cellular homeostasis through proteolysis. By this process, cells break down their own components in lysosomes. Autophagy can be classified into three categories: macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Macroautophagy involves membrane elongation and microautophagy involves membrane internalization, and both pathways undergo selective or non-selective processes that transport cytoplasmic components into lysosomes to be degraded. CMA, however, involves selective incorporation of cytosolic materials into lysosomes without membrane deformation. All three categories of autophagy have attracted much attention due to their involvement in various biological phenomena and their relevance to human diseases, such as neurodegenerative diseases and cancer. Clarification of the molecular mechanisms behind these processes is key to understanding autophagy and recent studies have made major progress in this regard, especially for the mechanisms of initiation and membrane elongation in macroautophagy and substrate recognition in microautophagy and CMA. Furthermore, it is becoming evident that the three categories of autophagy are related to each other despite their implementation by different sets of proteins and the involvement of completely different membrane dynamics. In this review, recent progress in macroautophagy, microautophagy, and CMA are summarized.


Assuntos
Autofagia Mediada por Chaperonas , Doenças Neurodegenerativas , Humanos , Microautofagia , Macroautofagia , Autofagia , Doenças Neurodegenerativas/metabolismo
17.
Autophagy ; 20(3): 629-644, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37963060

RESUMO

PYCARD (PYD and CARD domain containing), a pivotal adaptor protein in inflammasome assembly and activation, contributes to innate immunity, and plays an essential role in the pathogenesis of atherosclerosis and restenosis. However, its roles in microRNA biogenesis remain unknown. Therefore, this study aimed to investigate the roles of PYCARD in miRNA biogenesis and neointima formation using pycard knockout (pycard-/-) mice. Deficiency of Pycard reduced circulating miRNA profile and inhibited Mir17 seed family maturation. The systemic pycard knockout also selectively reduced the expression of AGO2 (argonaute RISC catalytic subunit 2), an important enzyme in regulating miRNA biogenesis, by promoting chaperone-mediated autophagy (CMA)-mediated degradation of AGO2, specifically in adipose tissue. Mechanistically, pycard knockout increased PRMT8 (protein arginine N-methyltransferase 8) expression in adipose tissue, which enhanced AGO2 methylation, and subsequently promoted its binding to HSPA8 (heat shock protein family A (Hsp70) member 8) that targeted AGO2 for lysosome degradation through chaperone-mediated autophagy. Finally, the reduction of AGO2 and Mir17 family expression prevented vascular injury-induced neointima formation in Pycard-deficient conditions. Overexpression of AGO2 or administration of mimic of Mir106b (a major member of the Mir17 family) prevented Pycard deficiency-mediated inhibition of neointima formation in response to vascular injury. These data demonstrate that PYCARD inhibits CMA-mediated degradation of AGO2, which promotes microRNA maturation, thereby playing a critical role in regulating neointima formation in response to vascular injury independently of inflammasome activity and suggest that modulating PYCARD expression and function may represent a powerful therapeutic strategy for neointima formation.Abbreviations: 6-AN: 6-aminonicotinamide; ACTB: actin, beta; aDMA: asymmetric dimethylarginine; AGO2: argonaute RISC catalytic subunit 2; CAL: carotid artery ligation; CALCOCO2: calcium binding and coiled-coil domain 2; CMA: chaperone-mediated autophagy; CTSB: cathepsin B; CTSD: cathepsin D; DGCR8: DGCR8 microprocessor complex subunit; DOCK2: dedicator of cyto-kinesis 2; EpiAdi: epididymal adipose tissue; HSPA8: heat shock protein family A (Hsp70) member 8; IHC: immunohistochemical; ISR: in-stent restenosis; KO: knockout; LAMP2: lysosomal-associated membrane protein 2; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; miRNA: microRNA; NLRP3: NLR family pyrin domain containing 3; N/L: ammonium chloride combined with leupeptin; PRMT: protein arginine methyltransferase; PVAT: peri-vascular adipose tissues; PYCARD: PYD and CARD domain containing; sDMA: symmetric dimethylarginine; ULK1: unc-51 like kinase 1; VSMCs: vascular smooth muscle cells; WT: wild-type.


Assuntos
Autofagia Mediada por Chaperonas , MicroRNAs , Lesões do Sistema Vascular , Animais , Camundongos , MicroRNAs/genética , Inflamassomos/metabolismo , Autofagia/fisiologia , Neointima , Proteínas de Ligação a RNA , Proteínas de Choque Térmico/metabolismo , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Proteína-Arginina N-Metiltransferases/metabolismo
18.
Adv Sci (Weinh) ; 11(3): e2306535, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37973552

RESUMO

BRAF V600E attracts wide attention in the treatment of colorectal cancer (CRC) as stratifying and predicting a refractory classification of CRC. Recent evidence indicates that Wnt/ß-catenin signaling is broadly activated and participates in the refractoriness of BRAF V600E CRC, but the underlying molecular mechanism needs to be elucidated. Here, heat shock 70 kDa protein 8 (HSPA8), an essential regulator in chaperone-mediated autophagy (CMA), is identified as a potential therapeutic target for advanced BRAF V600E CRC. These results show that HSPA8 is transcriptionally upregulated in BRAF V600E CRC, which promotes CMA-dependent degradation of caveolin-1 (CAV1) to release ß-catenin into the nucleus and thus activates the Wnt/ß-catenin pathway, contributing to metastasis and progression of BRAF V600E CRC. Of note, HSPA8 directly interacts with the KIFSN motif on CAV1, the interaction can be enhanced by p38 MAPK-mediated CAV1 S168 phosphorylation. Furthermore, pharmacological targeting HSPA8 by VER155008 exhibits synergistic effects with BRAF inhibitors on CRC mouse models. In summary, these findings discover the important role of the HSPA8/CAV1/ß-catenin axis in the development of refractory BRAF V600E CRC and highlight HSPA8 as a predictive biomarker and therapeutic target in clinical practice.


Assuntos
Autofagia Mediada por Chaperonas , Neoplasias Colorretais , Animais , Camundongos , beta Catenina/metabolismo , Caveolina 1/genética , Caveolina 1/metabolismo , Caveolina 1/uso terapêutico , Neoplasias Colorretais/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Proteínas Proto-Oncogênicas B-raf/uso terapêutico
19.
Autophagy ; 20(2): 457-459, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-37876225

RESUMO

The neuronal metastable proteome includes several aggregation-prone proteins related to neurodegeneration. The complex morphology of neurons with very thin processes and enhanced protein turnover therefore necessitates efficient local machinery to remove excessive protein. In recent work we revealed that chaperone-mediated autophagy (CMA) provides cargo for dendritic exocytic lysosomes, a mechanism that serves in the rapid removal of disease-relevant, supersaturated proteins such as TARDBP/TDP-43 (TAR DNA binding protein) and HTT (huntingtin). We found that lysosomal exocytosis requires docking of the lysosomal protein LAMP2B to the glutamatergic receptor scaffold DLG3/SAP102 and that it is regulated by GRIN/NMDA (N-methyl-D-aspartate)-receptor activity. Thus, the small caliber of dendritic processes might impose a need for local disposal of aggregation-prone proteins like TARDBP and HTT. Moreover, we observed that lysosomal exocytosis might serve in both protein removal and modulation of synaptic processes, and the latter might be an inevitable consequence of the necessity for local disposal of CMA clients in dendrites.


Assuntos
Autofagia Mediada por Chaperonas , Humanos , Autofagia/fisiologia , Proteoma/metabolismo , Neurônios , Lisossomos/metabolismo
20.
Food Chem Toxicol ; 184: 114378, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38097005

RESUMO

Evidence suggests that ferroptosis participates in kidney injury. However, the role of ferroptosis in antimony (Sb) induced nephrotoxicity and the mechanism are unknown. Here, we demonstrated that Sb induced injury in renal tubular epithelial cells (RTECs) and ferroptosis. Inhibition of ferroptosis reduced RTECs injury. Besides, elimination of reactive oxygen species (ROS) alleviated ferroptosis and RTECs injury. Moreover, exposure to Sb not only increased the co-localization of glutathione peroxidase 4 (GPX4) and LAMP1, but also decreased the levels of MEF2D and LRRK2, while increased the levels of HSC70, HSP90, and LAMP2a. These findings suggest that Sb activates chaperone-mediated autophagy (CMA), enhances lysosomal transport and subsequent degradation of GPX4, ultimately leads to ferroptosis. Additionally, up-regulation of lysosomal cationic channel, TRPML1, mitigated RTECs injury and ferroptosis. Mechanistically, up-regulation of TRPML1 mitigated the changes in CMA-associated proteins induced by Sb, diminished the binding of HSC70, HSP90, and TRPML1 with LAMP2a. Furthermore, NAC restored the decreased TRPML1 level caused by Sb. In summary, deficiency of TRPML1, secondary to increased ROS induced by Sb, facilitates the CMA-dependent degradation of GPX4, thereby leading to ferroptosis and RTECs injury. These findings provide insights into the mechanism underlying Sb-induced nephrotoxicity and propose TRPML1 as a promising therapeutic target.


Assuntos
Autofagia Mediada por Chaperonas , Ferroptose , Espécies Reativas de Oxigênio/metabolismo , Antimônio/toxicidade , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Proteínas de Choque Térmico HSP90 , Autofagia
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