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1.
Mol Cell ; 83(10): 1693-1709.e9, 2023 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-37207627

RESUMO

Cargo sequestration is a fundamental step of selective autophagy in which cells generate a double-membrane structure termed an "autophagosome" on the surface of cargoes. NDP52, TAX1BP1, and p62 bind FIP200, which recruits the ULK1/2 complex to initiate autophagosome formation on cargoes. How OPTN initiates autophagosome formation during selective autophagy remains unknown despite its importance in neurodegeneration. Here, we uncover an unconventional path of PINK1/Parkin mitophagy initiation by OPTN that does not begin with FIP200 binding or require the ULK1/2 kinases. Using gene-edited cell lines and in vitro reconstitutions, we show that OPTN utilizes the kinase TBK1, which binds directly to the class III phosphatidylinositol 3-kinase complex I to initiate mitophagy. During NDP52 mitophagy initiation, TBK1 is functionally redundant with ULK1/2, classifying TBK1's role as a selective autophagy-initiating kinase. Overall, this work reveals that OPTN mitophagy initiation is mechanistically distinct and highlights the mechanistic plasticity of selective autophagy pathways.


Assuntos
Mitofagia , Ubiquitina-Proteína Ligases , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Autofagossomos/metabolismo , Proteínas Reguladoras de Apoptose , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Autofagia
2.
Mol Cell ; 80(5): 779-795.e10, 2020 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-33207181

RESUMO

Protein aggregates disrupt cellular homeostasis, causing toxicity linked to neurodegeneration. Selective autophagic elimination of aggregates is critical to protein quality control, but how aggregates are selectively targeted for degradation is unclear. We compared the requirements for autophagy receptor proteins: OPTN, NBR1, p62, NDP52, and TAX1BP1 in clearance of proteotoxic aggregates. Endogenous TAX1BP1 is recruited to and required for the clearance of stress-induced aggregates, whereas ectopic expression of TAX1BP1 increases clearance through autophagy, promoting viability of human induced pluripotent stem cell-derived neurons. In contrast, TAX1BP1 depletion sensitizes cells to several forms of aggregate-induced proteotoxicity. Furthermore, TAX1BP1 is more specifically expressed in the brain compared to other autophagy receptor proteins. In vivo, loss of TAX1BP1 results in accumulation of high molecular weight ubiquitin conjugates and premature lipofuscin accumulation in brains of young TAX1BP1 knockout mice. TAX1BP1 mediates clearance of a broad range of cytotoxic proteins indicating therapeutic potential in neurodegenerative diseases.


Assuntos
Proteínas Reguladoras de Apoptose/deficiência , Autofagia , Encéfalo/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/deficiência , Proteínas de Neoplasias/deficiência , Doenças Neurodegenerativas/metabolismo , Agregação Patológica de Proteínas/metabolismo , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Encéfalo/patologia , Feminino , Células HEK293 , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lipofuscina/genética , Lipofuscina/metabolismo , Masculino , Camundongos , Camundongos Knockout , Proteínas de Neoplasias/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , Ratos , Ratos Sprague-Dawley , Ubiquitina/genética , Ubiquitina/metabolismo
3.
Proc Natl Acad Sci U S A ; 121(14): e2318039121, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38536750

RESUMO

Melanosomes are specific organelles dedicated to melanin synthesis and accumulation in melanocytes. Autophagy is suggestively involved in melanosome degradation, although the potential underlying molecular mechanisms remain elusive. In selective autophagy, autophagy receptors and E3-ligases are the key factors conferring cargo selectivity. In B16F10 cells, ß-mangostin efficiently induced melanosome degradation without affecting other organelles such as mitochondria, peroxisomes, and the endoplasmic reticulum. Among various autophagy receptors, optineurin (OPTN) contributes TANK-binding kinase 1 (TBK1)-dependently to melanosome degradation and its knockdown inhibited ß-mangostin-mediated melanosome degradation. OPTN translocation to melanosomes was dependent on its ubiquitin-binding domain. Moreover, OPTN-mediated TBK1 activation and subsequent TBK1-mediated S187 OPTN phosphorylation were essential for melanosome degradation. ß-mangostin increased K63-linked melanosome ubiquitination. Finally, the E3-ligase RCHY1 knockdown inhibited the melanosome ubiquitination required for OPTN- and TBK1-phosphorylation as well as melanosome degradation. This study suggests that melanophagy, melanosome-selective autophagy, contributes to melanosome degradation, and OPTN and RCHY1 are an essential autophagy receptor and a E3-ligase, respectively, conferring cargo selectivity in melanophagy.


Assuntos
Autofagia , Melanossomas , Melanossomas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Xantonas , Melanoma Experimental , Animais , Camundongos
4.
Am J Transplant ; 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38876367

RESUMO

Partial heart transplant (PHT) is a recent clinical innovation involving the transplantation of a segment of the heart (valves) directly from the deceased donor into the recipient patient. This procedure holds out the possibility of significant benefit, especially for pediatric patients because these grafts show growth potential after transplant, reducing or eliminating the current need for repeat procedures. The clinical process for donation and transplant of partial heart (PH) grafts generally follows an organ clinical pathway; however, the Food and Drug Administration has recently stated its intent to regulate PH as tissues, raising a host of regulatory considerations. PHT requires donor testing and eligibility determinations within a short, clinically viable timeframe and, similar to organ transplant, involves donor-recipient matching. Waitlist allocation policies that are a regulatory focus of the Organ Procurement and Transplantation Network including equity and efficiency may become relevant. Oversight of PHT by the Organ Procurement and Transplantation Network could be accomplished through interpretation of the vascular composite allograft definition or through designation by the US Department of Health and Human Services of PH grafts as organs. While some clinical questions remain unanswered, it is important to carefully address these regulatory considerations to support the emergence of this innovation and ensure the continued trust of the donating public and the patients who may benefit from PHT.

5.
Am J Transplant ; 24(2): 190-212, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37704059

RESUMO

The Organ Procurement and Transplantation Network conducts a robust death verification process when augmenting the United States transplant registry with external sources of data. Process enhancements added over 35,000 externally verified deaths across waitlist candidates and transplant recipients for all organs beginning in April 2022. Ninety-four percent of added posttransplant deaths occurred beyond 5 years posttransplant, and over 74% occurred beyond 10 years. Deceased donor solid organ recipients transplanted from January 1, 2010, through October 31, 2020, were analyzed from January and July 2022 Organ Procurement and Transplantation Network Standard Transplant Analysis and Research and the Scientific Registry of Transplant Recipients Standard Analysis Files to quantify the impact of including vs excluding unverified deaths (not releasable to researchers) on posttransplant patient survival estimates. Across all organs, 1- and 5-year posttransplant survival rates were not substantially impacted; meaningful differences were observed in 10-year survival among kidney recipients. These findings bear important implications for anyone who utilized transplant registry data to examine long-term outcomes prior to the updated verification process. Users of transplant surveillance data should interpret results of long-term outcomes cautiously, particularly differences across subpopulations, and the transplant community should identify ways to improve data quality and minimize the reporting burden on transplant institutions.


Assuntos
Obtenção de Tecidos e Órgãos , Humanos , Estados Unidos/epidemiologia , Sistema de Registros , Transplantados , Taxa de Sobrevida , Doadores de Tecidos
6.
Am J Transplant ; 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38521350

RESUMO

Donation after circulatory death (DCD) could account for the largest expansion of the donor allograft pool in the contemporary era. However, the organ yield and associated costs of normothermic regional perfusion (NRP) compared to super-rapid recovery (SRR) with ex-situ normothermic machine perfusion, remain unreported. The Organ Procurement and Transplantation Network (December 2019 to June 2023) was analyzed to determine the number of organs recovered per donor. A cost analysis was performed based on our institution's experience since 2022. Of 43 502 donors, 30 646 (70%) were donors after brain death (DBD), 12 536 (29%) DCD-SRR and 320 (0.7%) DCD-NRP. The mean number of organs recovered was 3.70 for DBD, 3.71 for DCD-NRP (P < .001), and 2.45 for DCD-SRR (P < .001). Following risk adjustment, DCD-NRP (adjusted odds ratio 1.34, confidence interval 1.04-1.75) and DCD-SRR (adjusted odds ratio 2.11, confidence interval 2.01-2.21; reference: DBD) remained associated with greater odds of allograft nonuse. Including incomplete and completed procurement runs, the total average cost of DCD-NRP was $9463.22 per donor. By conservative estimates, we found that approximately 31 donor allografts could be procured using DCD-NRP for the cost equivalent of 1 allograft procured via DCD-SRR with ex-situ normothermic machine perfusion. In conclusion, DCD-SRR procurements were associated with the lowest organ yield compared to other procurement methods. To facilitate broader adoption of DCD procurement, a comprehensive understanding of the trade-offs inherent in each technique is imperative.

7.
Clin Transplant ; 38(3): e15273, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38516921

RESUMO

INTRODUCTION: OPTN Policy 3.7D, implemented January 5, 2023, mandates that all kidney transplant programs modify waiting time for candidates affected by race-inclusive eGFR calculations. We report the early impact of this policy change. METHODS: Our transplant program reviewed all listed transplant candidates and identified patients potentially eligible for waiting time modification. Eligible candidates received waiting time modification after submission of supporting evidence to the OPTN. We reviewed the impact on waiting time and transplant activity through October 1, 2023. RESULTS: Forty-six adult patients on our center's active waiting list self-identified as Black/African American. 25 (54.3%) candidates qualified for waiting time modification. A median 451 (321, 1543.5) additional days of waiting time was added for qualifying patients. Of the 25 patients who qualified for waiting time modification, 11 patients received a deceased donor kidney in the early period following waiting time modification, including 5 patients transplanted within 1 month after modification. CONCLUSIONS: Policy 3.7D is one of few national mandates to address specifically structural racism within transplantation. Implementation has yielded near immediate effects with greater than 40% of time-adjusted patients at our center receiving a deceased donor kidney transplant in the initial months after policy enactment. Early assessment demonstrates great potential impact for this policy.


Assuntos
Transplante de Rim , Obtenção de Tecidos e Órgãos , Transplantes , Adulto , Humanos , Listas de Espera , Doadores de Tecidos , Transplante de Rim/métodos , Políticas
8.
Clin Transplant ; 38(1): e15158, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37788166

RESUMO

OBJECTIVES: End-stage lung disease from primary pulmonary hypertension (PPHTN) and pulmonary venous-occlusive disease (PVOD) may require lung transplantation (LT). While medical therapies exist for the palliation of PPHTN, no therapies exist for PVOD. The study's objective is to compare outcomes of LT in these patients. METHODS: Patients with PPHTN and PVOD who had undergone LT were identified in the UNOS database (2005-2022). Univariable analyses compared differences between groups in demographic, clinical, and post-transplant outcomes. Multivariable logistic regression examined the association between the diagnosis group and survival. Overall survival time between groups was compared using the Kaplan-Meier method. RESULTS: Six hundred and ninety-six PPHTN and 78 PVOD patients underwent LT during the study period. Patients with PVOD had lower pulmonary artery mean pressure (47 vs. 53 mmHg, p < .001), but higher cardiac output (4.51 vs. 4.31 L/min, p = .04). PVOD patients were more likely to receive lungs from donation after cardiac death donors (7.7 vs. 2.9%, p = .04). There were no differences in postoperative complications or length of stay. PVOD was associated with superior survival at 30-day (100 vs. 93%, p = .02) and 90-day post-transplant (93 vs. 83%, p = .03), but not at later time points. In multivariable analyses, PVOD and brain death donor use were associated with better survival up to 90-day mark. CONCLUSIONS: Patients undergoing LT for PVOD had better initial survival, which disappeared after 1 year of transplantation. Donation after circulatory death donor use had a short-term survival disadvantage.


Assuntos
Hipertensão Pulmonar , Transplante de Pulmão , Hipertensão Arterial Pulmonar , Pneumopatia Veno-Oclusiva , Humanos , Hipertensão Arterial Pulmonar/complicações , Pneumopatia Veno-Oclusiva/complicações , Pneumopatia Veno-Oclusiva/diagnóstico , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/cirurgia , Hipertensão Pulmonar/diagnóstico , Pulmão
9.
Clin Transplant ; 38(3): e15280, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38485662

RESUMO

INTRODUCTION: Some studies have shown increased incidence of Primary Graft Dysfunction (PGD) after heart and lung procurement for heart transplant recipients. There have been limited investigations of the impact of lung procurement on heart procurement and the potential effects of the exposure to the type of lung preservation solution, the volume of the lung preservation solution and adequacy of decompression of the heart during heart and lung procurement and the impact on heart transplant outcomes. METHODS: Adult heart transplant recipients in the UNOS database recorded from January 1, 2000 to June 30, 2022 formed the study cohort. Any heart that was procured with a lung team that utilized Perfadex preservation solution (XVIVO, Gothenburg, Sweden) was classified as exposed to Perfadex and otherwise classified as not exposed to Perfadex. Lung procurements performed with a preservation solution other than Perfadex or unknown were excluded (n = 2486). Simple comparisons were made with t-tests or chi-squared tests. Logistic regression models were used to predict 30 day and 1 year survival. Accelerated failure time models were employed to analyze time to death and time to rejection. RESULTS: The cohort consisted of 34 192 heart transplants, of which 21 928 donors were not exposed to Perfadex (64.1%). There were statistically, but not clinically, significant differences in donor characteristics for these groups including in donor age (33.34 ± 11.01 not exposed vs. 30.70 ± 10.69 exposed; p < .001), diabetic donor (4% not exposed vs. 3% exposed; p = .004), and ischemic time (3.28 ± 1.09 h not exposed vs. 3.24 ± 1.05 h exposed; p = .002). In adjusted models, for all included donors, Perfadex exposure was associated with increased short term mortality, but no long term difference (1 year mortality OR 1.10, p = .014). CONCLUSION: Perfadex exposure was associated with increased short-term mortality for heart transplant recipients. Mechanistic investigation is warranted.


Assuntos
Citratos , Transplante de Coração , Transplante de Pulmão , Obtenção de Tecidos e Órgãos , Adulto , Humanos , Pulmão , Doadores de Tecidos , Sobrevivência de Enxerto , Estudos Retrospectivos
10.
Pediatr Nephrol ; 39(8): 2483-2493, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38216782

RESUMO

BACKGROUND: Over one thousand pediatric kidney transplant candidates are added to the waitlist annually, yet the prospective time spent waiting is unknown for many. Our study fills this gap by identifying variables that impact waitlist time and by creating an index to predict the likelihood of a pediatric candidate receiving a transplant within 1 year of listing. This index could be used to guide patient management by giving clinicians a potential timeline for each candidate's listing based on a unique combination of risk factors. METHODS: A retrospective analysis of 3757 pediatric kidney transplant candidates from the 2014 to 2020 OPTN/UNOS database was performed. The data was randomly divided into a training set, comprising two-thirds of the data, and a testing set, comprising one-third of the data. From the training set, univariable and multivariable logistic regressions were used to identify significant predictive factors affecting wait times. A predictive index was created using variables significant in the multivariable analysis. The index's ability to predict likelihood of transplantation within 1 year of listing was validated using ROC analysis on the training set. Validation of the index using ROC analysis was repeated on the testing set. RESULTS: A total of 10 variables were found to be significant. The five most significant variables include the following: blood group, B (OR 0.65); dialysis status (OR 3.67); kidney disease etiology, SLE (OR 0.38); and OPTN region, 5 (OR 0.54) and 6 (OR 0.46). ROC analysis of the index on the training set yielded a c-statistic of 0.71. ROC analysis of the index on the testing set yielded a c-statistic of 0.68. CONCLUSIONS: This index is a modest prognostic model to assess time to pediatric kidney transplantation. It is intended as a supplementary tool to guide patient management by providing clinicians with an individualized prospective timeline for each candidate. Early identification of candidates with potential for prolonged waiting times may help encourage more living donation including paired donation chains.


Assuntos
Transplante de Rim , Listas de Espera , Humanos , Transplante de Rim/estatística & dados numéricos , Criança , Masculino , Feminino , Estudos Retrospectivos , Adolescente , Fatores de Tempo , Pré-Escolar , Fatores de Risco , Lactente , Falência Renal Crônica/cirurgia
11.
Artif Organs ; 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38803277

RESUMO

BACKGROUND: The Organ Procurement and Transplantation Network (OPTN) implemented modifications in 2018 to the adult heart transplant allocation system to better stratify the most medically urgent transplant candidates. We evaluated the impact of these changes on patients supported by a durable left ventricular assist device (LVAD) with chronic kidney disease (CKD). OBJECTIVE: To evaluate the impact of the OPTN policy change on patients supported by durable left ventricular assist devices (LVAD) with chronic kidney disease (CKD). METHODS: We performed an analysis of patients from the United Network of Organ Sharing Database supported by durable LVAD listed for a heart transplant (HT) between October 17, 2016 and September 30, 2021. Patients were divided into two groups: pre- and postpolicy, depending on whether they were listed on or prior to October 17, 2018. Patients who were on dialysis prior to surgery or discharge were excluded from the analysis. Patients with simultaneous heart and kidney transplants were excluded. Patients who were listed for transplant prepolicy change but transplanted postpolicy change were excluded. This cohort was then subdivided into degrees of CKD based on estimated glomerular filtration rate (eGFR), which resulted in 678 patients (23.7%) in Stage 1 (GFR ≥89.499) (Prepolicy: 345, Postpolicy: 333), 1233 (43.1%) in Stage 2 (89.499 > GFR ≥ 59.499) (Prepolicy: 618, Postpolicy: 615), 613 (21.4%) in Stage 3a (59.499 > GFR ≥ 44.499) (Prepolicy: 291, Postpolicy: 322), 294 (10.3%) in Stage 3b (44.499 > GFR ≥ 29.499) (Prepolicy: 143, Postpolicy: 151), 36 (1.3%) in Stage 4 (29.499 > GFR ≥ 15) (Prepolicy: 21, Postpolicy: 15), and 9 (0.3%) in Stage 5 (15 > GFR) (Prepolicy: 4, Postpolicy: 5). The primary outcome was 1-year and 2-year post-HT survival. RESULTS: There were 2863 patients who met the study criteria (1422 prepolicy, 1441 postpolicy). Overall survival, regardless of CKD stage, was lower following the policy change (p < 0.01). There was a similar risk of primary graft failure (PGF) in the pre- and postpolicy period (1.8% vs. 1.2%, p = 0.26). 1-year overall survival was 93% (91, 94) and 89% (87, 91) in the pre- and postpolicy periods, respectively. 2-year overall survival was 89% (88, 91) and 85% (82, 87) in the pre- and postpolicy periods, respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 1 -year survival was 93% (91, 95), 92% (90,93), 89% (86, 91), 89% (86, 93), 80% (68, 94), and 100% (100, 100), respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 2-year survival was 91% (88, 93), 88% (86, 90), 84% (81, 88), 84% (80, 89), 73% (59, 90), and 100% (100, 100), respectively. Patients with CKD 1 and 2 had better survival compared to those with CKD 3 (p < 0.01) and CKD 4 and 5 (p = 0.03) in the pre- and postpolicy periods. Patients with CKD 3 did not have a survival advantage over those with CKD 4 and 5 (p = 0.25). On cox regression analysis, advancing degrees of CKD were associated with an increased risk of mortality. CONCLUSIONS: Patients with LVAD support had decreased overall survival after the OPTN policy change. Patients with more advanced CKD had lower survival than patients without advanced CKD, though they were not impacted by the OPTN policy change.

12.
Mol Cell Neurosci ; 127: 103904, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37918554

RESUMO

Optineurin (OPTN) gene is a marker of amyotrophic lateral sclerosis (ALS). However, the role of optineurin protein (OPTN) in ALS pathology is unclear, even though it is known to regulate autophagy, apoptosis, and other survival-death cellular processes. Genetic analysis of Indian ALS patients by our group ascertained a novel mutation K489E in the OPTN gene. To identify the molecular mechanism associated with OPTN and its mutation, we developed an in-vitro cell model using SH-SY5Y cells harbouring OPTN and OPTN-K489E mutation along with its control vector. Since we observed a significant decrease in cell viability in the mutant, we measured the expressions of genes and proteins mediating apoptosis, necroptosis, and autophagy, to establish the role of OPTN in cell death regulation. Our results show that OPTN-K489E mutation changes the relative gene expressions of miRNA-9, REST, CoREST and BDNF, and causes apoptosis. We also observed an up-regulation in the expressions of necroptosis mediated genes RIPK1, RIPK3, and MLKL and autophagy mediated genes TBK1, P62, and LC3II. The results of FACS analyses revealed that this mutation promotes apoptotic and necroptotic processes confirming the pathogenicity of OPTN-K489E.


Assuntos
Esclerose Lateral Amiotrófica , Neuroblastoma , Humanos , Esclerose Lateral Amiotrófica/metabolismo , Mutação , Morte Celular , Apoptose/genética
13.
Acta Biochim Biophys Sin (Shanghai) ; 56(7): 1044-1054, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38660717

RESUMO

Esophagus cancer (EC) is one of the most aggressive malignant digestive system tumors and has a high clinical incidence worldwide. Magnolol, a natural compound, has anticancer effects on many cancers, including esophageal carcinoma, but the underlying mechanism has not been fully elucidated. Here, we first find that magnolol inhibits the proliferation of esophageal carcinoma cells and enhances their autophagy activity in a dose- and time-dependent manner. This study demonstrates that magnolol increases the protein levels of LC3 II, accompanied by increased HACE1 protein levels in both esophageal carcinoma cells and xenograft tumors. HACE1-knockout (KO) cell lines are generated, and the ablation of HACE1 eliminates the anti-proliferative and autophagy-inducing effects of magnolol on esophageal carcinoma cells. Additionally, our results show that magnolol primarily promotes HACE1 expression at the transcriptional level. Therefore, this study shows that magnolol primarily exerts its antitumor effect by activating HACE1-OPTN axis-mediated autophagy. It can be considered a promising therapeutic drug for esophageal carcinoma.


Assuntos
Autofagia , Compostos de Bifenilo , Proliferação de Células , Neoplasias Esofágicas , Lignanas , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/tratamento farmacológico , Autofagia/efeitos dos fármacos , Autofagia/genética , Lignanas/farmacologia , Humanos , Linhagem Celular Tumoral , Compostos de Bifenilo/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Camundongos , Camundongos Nus , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Proc Natl Acad Sci U S A ; 118(24)2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-34099552

RESUMO

TANK-binding kinase 1 (TBK1) is a multifunctional kinase with an essential role in mitophagy, the selective clearance of damaged mitochondria. More than 90 distinct mutations in TBK1 are linked to amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia, including missense mutations that disrupt the abilities of TBK1 to dimerize, associate with the mitophagy receptor optineurin (OPTN), autoactivate, or catalyze phosphorylation. We investigated how ALS-associated mutations in TBK1 affect Parkin-dependent mitophagy using imaging to dissect the molecular mechanisms involved in clearing damaged mitochondria. Some mutations cause severe dysregulation of the pathway, while others induce limited disruption. Mutations that abolish either TBK1 dimerization or kinase activity were insufficient to fully inhibit mitophagy, while mutations that reduced both dimerization and kinase activity were more disruptive. Ultimately, both TBK1 recruitment and OPTN phosphorylation at S177 are necessary for engulfment of damaged mitochondra by autophagosomal membranes. Surprisingly, we find that ULK1 activity contributes to the phosphorylation of OPTN in the presence of either wild-type or kinase-inactive TBK1. In primary neurons, TBK1 mutants induce mitochondrial stress under basal conditions; network stress is exacerbated with further mitochondrial insult. Our study further refines the model for TBK1 function in mitophagy, demonstrating that some ALS-linked mutations likely contribute to disease pathogenesis by inducing mitochondrial stress or inhibiting mitophagic flux. Other TBK1 mutations exhibited much less impact on mitophagy in our assays, suggesting that cell-type-specific effects, cumulative damage, or alternative TBK1-dependent pathways such as innate immunity and inflammation also factor into the development of ALS in affected individuals.


Assuntos
Esclerose Lateral Amiotrófica/genética , Demência Frontotemporal/genética , Mitofagia/genética , Mutação de Sentido Incorreto/genética , Proteínas Serina-Treonina Quinases/genética , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Proteínas de Ciclo Celular/metabolismo , Predisposição Genética para Doença , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Cinética , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/genética , Mitocôndrias/patologia , Proteínas Mutantes/metabolismo , Estresse Oxidativo , Fosforilação , Domínios Proteicos , Multimerização Proteica , Proteínas Serina-Treonina Quinases/química
15.
Am J Transplant ; 23(8): 1097-1101, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37023857

RESUMO

Early (ie, without a mandated abstinence period) liver transplantation for alcohol-associated liver disease is the fastest-growing indication for liver transplantation in the United States. Despite widespread adoption, there is no standardization of practice or policies across transplant centers, nor are there any quality metrics from regulatory organizations specific to alcohol, all of which have likely contributed to confirmed disparities in transplant access and patient outcomes. In this article, we propose new mandates and best practices that could be put forth by the organ procurement and transplantation network regarding processes related to candidate selection, monitoring of alcohol use, and services to prevent and treat harmful alcohol use among early transplant candidates and recipients. We hope that this article stimulates discussion and leads to policy changes to maximize equity and quality of transplant care.


Assuntos
Hepatopatias , Transplante de Fígado , Obtenção de Tecidos e Órgãos , Transplantes , Humanos , Estados Unidos , Listas de Espera
16.
Am J Transplant ; 23(1): 72-77, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36695624

RESUMO

The importance of waitlist (WL) mortality risk estimates will increase with the adoption of the US Composite Allocation Score (CAS) system. Calibration is rarely assessed in clinical prediction models, yet it is a key factor in determining access to lung transplant. We assessed the calibration of the WL-lung allocation score (LAS)/CAS models and developed alternative models to minimize miscalibration. Scientific Registry of Transplant Recipients data from 2015 to 2020 were used to assess the calibration of the WL model and for subgroups (age, sex, diagnosis, and race/ethnicity). Three recalibrated models were developed and compared: (1) simple recalibration model (SRM), (2) weighted recalibration model 1 (WRM1), and (3) weighted recalibration model 2 (WRM2). The current WL-LAS/CAS model underestimated risk for 78% of individuals (predicted mortality risk, <42%) and overpredicted risk for 22% of individuals (predicted mortality risk, ≥42%), with divergent results among subgroups. Error measures improved in SRM, WRM1, and WRM2. SRM generally preserved candidate rankings, whereas WRM1 and WRM2 led to changes in ranking by age and diagnosis. Differential miscalibration occurred in the WL-LAS/CAS model, which improved with recalibration measures. Further inquiry is needed to develop mortality models in which risk predictions approximate observed data to ensure accurate ranking and timely access to transplant. IMPACT: With changes to the lung transplant allocation system planned in 2023, evaluation of the accuracy and precision of survival models used to rank candidates for lung transplant is important. The waitlist model underpredicts risk for 78% of US transplant candidates with an unequal distribution of miscalibration across subgroups leading to inaccurate ranking of transplant candidates. This work will serve to inform future efforts to improve modeling efforts in the US lung transplant allocation system.


Assuntos
Transplante de Pulmão , Obtenção de Tecidos e Órgãos , Humanos , Listas de Espera , Transplantados , Etnicidade , Pulmão
17.
Am J Transplant ; 23(5): 629-635, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37130619

RESUMO

To determine the effect of donor hepatitis C virus (HCV) infection on kidney transplant (KT) outcomes in the era of direct-acting antiviral (DAA) medications, we examined 68,087 HCV-negative KT recipients from a deceased donor between March 2015 and May 2021. A Cox regression analysis was used to estimate adjusted hazard ratios (aHRs) of KT failure, incorporating inverse probability of treatment weighting to control for patient selection to receive an HCV-positive kidney (either nucleic acid amplification test positive [NAT+, n = 2331] or antibody positive (Ab+)/NAT- [n = 1826]) based on recipient characteristics. Compared with kidney from HCV-negative donors, those from Ab+/NAT- (aHR = 0.91; 95% confidence interval [CI], 0.75-1.10) and HCV NAT+ (aHR = 0.89; 95% CI, 0.73-1.08) donors were not associated with an increased risk of KT failure over 3 years after transplant. Moreover, HCV NAT+ kidneys were associated with a higher 1-year estimated glomerular filtration (63.0 vs 61.0 mL/min/1.73 m2, P = .007) and lower risk of delayed graft function (aOR = 0.76; 95% CI, 0.68-0.84) compared with HCV-negative kidneys. Our findings suggest that donor HCV positivity is not associated with an elevated risk of graft failure. The inclusion of donor HCV status in the Kidney Donor Risk Index may no longer be appropriate in contemporary practice.


Assuntos
Hepatite C Crônica , Hepatite C , Transplante de Rim , Humanos , Hepacivirus , Transplante de Rim/efeitos adversos , Antivirais/uso terapêutico , Hepatite C Crônica/tratamento farmacológico , Doadores de Tecidos
18.
Am J Transplant ; 23(1): 5-10, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36695621

RESUMO

The Organ Procurement and Transplantation Network, an arm of the Health Resources and Services Administration, has a contract with the United Network for Organ Sharing since 1986 to provide central oversight of organ donation and transplants in the United States. The United Network for Organ Sharing has recently come under scrutiny, prompting a review by the National Academies of Sciences, Engineering, and Medicine as summarized in its recent report and also by the US Senate Finance Committee. The national news services have opined about organ donation ethics, access to transplantation particularly for medically underserved populations, and management of organ transplantation data. These critiques raise important concerns that deserve our best response as a transplant community. Broadly, we suggest that the data management approach of the Organ Procurement and Transplantation Network be replaced with a patient-centric omnichannel network in which all donor and recipient data exist in a single longitudinal record that can be used by all applications. A more comprehensive and standardized approach to donor data collection would drive quality improvement across organ procurement organizations and help address inequities in transplantation. Finally, a substantial increase in organ donation would be prompted by considering organ donors as a public health resource, meriting transparent publicly available data collection with respect to organ donor referral, screening, and management.


Assuntos
Transplante de Órgãos , Obtenção de Tecidos e Órgãos , Transplantes , Humanos , Estados Unidos , Doadores de Tecidos , United States Health Resources and Services Administration
19.
Am J Transplant ; 23(2): 223-231, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36695688

RESUMO

The median waiting time (MWT) to deceased donor kidney transplant is of interest to patients, clinicians, and the media but remains elusive due to both methodological and philosophical challenges. We used Organ Procurement and Transplantation Network data from January 2003 to March 2022 to estimate MWTs using various methods and timescales, applied overall, by era, and by candidate demographics. After rising for a decade, the overall MWT fell to 5.19 years between 2015 and 2018 and declined again to 4.05 years (April 2021 to March 2022), based on the Kaplan-Meier method applied to period-prevalent cohorts. MWTs differed markedly by blood type, donor service area, and pediatric vs adult status, but to a lesser degree by race/ethnicity. Choice of methodology affected the magnitude of these differences. Instead of waiting years for an answer, reliable kidney MWT estimates can be obtained shortly after a policy is implemented using the period-prevalent Kaplan-Meier approach, a theoretical but useful construct for which we found no evidence of bias compared with using incident cohorts. We recommend this method be used complementary to the competing risks approach, under which MWT is often inestimable, to fill the present information void concerning the seemingly simple question of how long it takes to get a kidney transplant in the United States.


Assuntos
Transplante de Rim , Obtenção de Tecidos e Órgãos , Adulto , Humanos , Criança , Estados Unidos , Doadores de Tecidos , Etnicidade , Listas de Espera , Rim
20.
Am J Transplant ; 23(3): 401-407, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36695700

RESUMO

Using California Tuberculosis (TB) Registry data from 2010-2020, we compared the presentation and outcomes of patients with TB aged >15 years with and without solid organ transplantation (SOT). We matched to the United Network for Organ Sharing registry for 1987-2020 and the estimated time from transplantation to the diagnosis of TB, the incidence of posttransplant TB, and the probability of death and graft failure in SOT recipients with TB, compared to those without TB. From 2010-2020, there were 148 posttransplant TB cases. Patients with posttransplant TB were more likely to have extrapulmonary disease and more than twice as likely to die as TB patients without SOT (relative risk [RR], 2.2; 95% confidence interval [CI], 1.6-2.9). The median time from transplantation to TB diagnosis was 1.2 years, with the shortest time among lung transplant recipients. The incidence of TB disease among Californians with SOT was 56.0 per 100 000 person-years. The risk of death was higher among SOT recipients with posttransplant TB than those without (adjusted hazard ratio, 2.8; 95% CI, 2.0-4.1); the risk of graft failure was higher among kidney transplant recipients with posttransplant TB than those without (adjusted hazard ratio, 3.4; 95% CI, 1.7-6.9). An increased risk of death and graft failure in SOT recipients with posttransplant TB highlights the need for enhanced pretransplant TB prevention.


Assuntos
Transplante de Órgãos , Tuberculose , Humanos , Transplantados , Fatores de Risco , Transplante de Órgãos/efeitos adversos , California
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