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1.
J Biol Chem ; 299(2): 102821, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36563857

RESUMO

Tauopathies are neurodegenerative diseases caused by pathologic misfolded tau protein aggregation in the nervous system. Population studies implicate EIF2AK3 (eukaryotic translation initiation factor 2 alpha kinase 3), better known as PERK (protein kinase R-like endoplasmic reticulum kinase), as a genetic risk factor in several tauopathies. PERK is a key regulator of intracellular proteostatic mechanisms-unfolded protein response and integrated stress response. Previous studies found that tauopathy-associated PERK variants encoded functional hypomorphs with reduced signaling in vitro. But, it remained unclear how altered PERK activity led to tauopathy. Here, we chemically or genetically modulated PERK signaling in cell culture models of tau aggregation and found that PERK pathway activation prevented tau aggregation, whereas inhibition exacerbated tau aggregation. In primary tauopathy patient brain tissues, we found that reduced PERK signaling correlated with increased tau neuropathology. We found that tauopathy-associated PERK variants targeted the endoplasmic reticulum luminal domain; and two of these variants damaged hydrogen bond formation. Our studies support that PERK activity protects against tau aggregation and pathology. This may explain why people carrying hypomorphic PERK variants have increased risk for developing tauopathies. Finally, our studies identify small-molecule augmentation of PERK signaling as an attractive therapeutic strategy to treat tauopathies by preventing tau pathology.


Assuntos
Agregados Proteicos , Agregação Patológica de Proteínas , eIF-2 Quinase , Proteínas tau , Humanos , Suscetibilidade a Doenças , eIF-2 Quinase/química , eIF-2 Quinase/genética , eIF-2 Quinase/metabolismo , Mutação , Fatores de Risco , Proteínas tau/química , Proteínas tau/metabolismo , Tauopatias/metabolismo , Tauopatias/patologia
2.
Am J Pathol ; 193(11): 1721-1739, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-36535406

RESUMO

Activating transcription factor 6 (ATF6), a key regulator of the unfolded protein response, plays a key role in endoplasmic reticulum function and protein homeostasis. Variants of ATF6 that abrogate transcriptional activity cause morphologic and molecular defects in cones, clinically manifesting as the human vision loss disease achromatopsia (ACHM). ATF6 is expressed in all retinal cells. However, the effect of disease-associated ATF6 variants on other retinal cell types remains unclear. Herein, this was investigated by analyzing bulk RNA-sequencing transcriptomes from retinal organoids generated from patients with ACHM, carrying homozygous loss-of-function ATF6 variants. Marked dysregulation in mitochondrial respiratory complex gene expression and disrupted mitochondrial morphology in ACHM retinal organoids were identified. This indicated that loss of ATF6 leads to previously unappreciated mitochondrial defects in the retina. Next, gene expression from control and ACHM retinal organoids were compared with transcriptome profiles of seven major retinal cell types generated from recent single-cell transcriptomic maps of nondiseased human retina. This indicated pronounced down-regulation of cone genes and up-regulation in Müller glia genes, with no significant effects on other retinal cells. Overall, the current analysis of ACHM patient retinal organoids identified new cellular and molecular phenotypes in addition to cone dysfunction: activation of Müller cells, increased endoplasmic reticulum stress, disrupted mitochondrial structure, and elevated respiratory chain activity gene expression.


Assuntos
Retina , Células Fotorreceptoras Retinianas Cones , Humanos , Retina/metabolismo , Células Fotorreceptoras Retinianas Cones/metabolismo , Estresse do Retículo Endoplasmático/genética , Organoides/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Fator 6 Ativador da Transcrição/genética , Fator 6 Ativador da Transcrição/metabolismo
3.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34561305

RESUMO

Endoplasmic reticulum (ER) stress and Unfolded Protein Response (UPR) signaling promote the pathology of many human diseases. Loss-of-function variants of the UPR regulator Activating Transcription Factor 6 (ATF6) cause severe congenital vision loss diseases such as achromatopsia by unclear pathomechanisms. To investigate this, we generated retinal organoids from achromatopsia patient induced pluripotent stem cells carrying ATF6 disease variants and from gene-edited ATF6 null hESCs. We found that achromatopsia patient and ATF6 null retinal organoids failed to form cone structures concomitant with loss of cone phototransduction gene expression, while rod photoreceptors developed normally. Adaptive optics retinal imaging of achromatopsia patients carrying ATF6 variants also showed absence of cone inner/outer segment structures but preserved rod structures, mirroring the defect in cone formation observed in our retinal organoids. These results establish that ATF6 is essential for human cone development. Interestingly, we find that a selective small molecule ATF6 signaling agonist restores the transcriptional activity of some ATF6 disease-causing variants and stimulates cone growth and gene expression in patient retinal organoids carrying these variants. These findings support that pharmacologic targeting of the ATF6 pathway can promote human cone development and should be further explored for blinding retinal diseases.


Assuntos
Fator 6 Ativador da Transcrição/genética , Defeitos da Visão Cromática/genética , Retina/citologia , Células Fotorreceptoras Retinianas Cones/patologia , Fator 6 Ativador da Transcrição/agonistas , Fator 6 Ativador da Transcrição/metabolismo , Opsinas dos Cones/genética , Expressão Gênica , Células HEK293 , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Organoides , Retina/diagnóstico por imagem , Células Fotorreceptoras Retinianas Cones/fisiologia , Visão Ocular/genética
4.
Adv Exp Med Biol ; 1415: 493-498, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37440077

RESUMO

Rhodopsin is a G-protein-coupled receptor that is specifically and abundantly expressed in rod photoreceptors. Over 150 rhodopsin mutations cause autosomal dominant retinitis pigmentosa (adRP). The most common mutation in the United States is the conversion of proline to histidine at position 23 (P23H) in the N-terminal domain of rhodopsin. We previously found that P23H rhodopsin was misfolded, ubiquitinylated, and rapidly degraded. Here, we investigated the role of lysine residues on P23H rhodopsin ubiquitinylation and turnover. We transfected HEK293 cells with a P23H human rhodopsin construct where all 11 lysine residues were mutated to arginine (K-null P23H). We found that the K-null P23H rhodopsin was significantly less ubiquitylated than intact P23H rhodopsin. We found that K-null P23H protein turnover was significantly slower compared to P23H rhodopsin through cycloheximide chase analysis. Finally, we also generated a wild-type rhodopsin construct where all lysines were converted to arginine and found significantly reduced ubiquitylation. Our findings identify ubiquitinylation of lysine residues as an important posttranslational modification involved in P23H rhodopsin protein degradation.


Assuntos
Lisina , Rodopsina , Humanos , Animais , Rodopsina/metabolismo , Lisina/metabolismo , Proteólise , Células HEK293 , Mutação , Ubiquitinação , Modelos Animais de Doenças
5.
Exp Eye Res ; 222: 109172, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35803332

RESUMO

Sporadic Creutzfeldt-Jakob disease (sCJD) is the most commonly diagnosed human prion disease caused by the abnormal misfolding of the 'cellular' prion protein (PrPC) into the transmissible 'scrapie-type' prion form (PrPSc). Neuropathologic evaluation of brains with sCJD reveals abnormal PrPSc deposits primarily in grey matter structures, often associated with micro-vacuolar spongiform changes in neuropil, neuronal loss, and gliosis. Abnormal PrPSc deposits have also been reported in the retina of patients with sCJD, but few studies have characterized the morphology of these retinal PrPSc deposits or evaluated for any retinal neurodegenerative changes. We performed histopathologic and morphometric analyses of retinal and brain prion deposits in 14 patients with sCJD. Interestingly, we discovered that the morphology of retinal PrPSc deposits generally differs from that of brain PrPSc deposits in terms of size and shape. We found that retinal PrPSc deposits consistently localize to the outer plexiform layer of the retina. Additionally, we observed that the retinal PrPSc deposits are not associated with the spongiform change, neuronal loss, and gliosis often seen in the brain. The stereotypic morphology and location of PrPSc deposits in sCJD retinas may help guide the use of ocular imaging devices in the detection of these deposits for a clinical diagnosis.


Assuntos
Síndrome de Creutzfeldt-Jakob , Príons , Doenças Retinianas , Encéfalo/patologia , Síndrome de Creutzfeldt-Jakob/diagnóstico , Síndrome de Creutzfeldt-Jakob/metabolismo , Síndrome de Creutzfeldt-Jakob/patologia , Gliose/patologia , Humanos , Retina/metabolismo , Doenças Retinianas/patologia
6.
Retina ; 42(4): 824-830, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35174798

RESUMO

PURPOSE: To report the clinicopathologic correlation of a case of bilateral serpiginous-like chorioretinitis (SLC) associated with unilateral ciliochoroidal melanoma. METHODS: A 71-year-old white woman was diagnosed with progressive SLC in both eyes associated with ciliochoroidal melanoma in the right eye. Clinical findings and imaging before and after enucleation in the right eye were correlated to histologic and immunohistochemistry sections. RESULTS: Examination and imaging identified a peripheral bilobed amelanotic lesion with low reflectivity on B-scan ultrasound with an associated exudative detachment in the right eye. Additionally, multiple areas of new SLC lesions in the macula and peripapillary region in the right eye and along the inferior arcade in the left eye were observed. Oncologic evaluation confirmed a Class 2, ciliochoroidal melanoma, and the eye was enucleated. Autoimmune and infectious laboratory evaluations for the etiology of the SLC lesions were negative. Histopathology of the enucleated eye confirmed the diagnosis of uveal melanoma with lymphocytic inflammation at the edges of the tumor itself and in the areas of discrete SLC lesions. Immunohistochemistry identified similar predominantly CD3 and CD8 T cells and fewer CD20 B cells in both regions. CONCLUSION: Serpiginous-like chorioretinitis may present as a paraneoplastic, predominantly T-lymphocyte inflammation associated with intraocular tumor such as uveal melanoma.


Assuntos
Coriorretinite , Melanoma , Neoplasias Uveais , Idoso , Coriorretinite/complicações , Coriorretinite/diagnóstico , Feminino , Humanos , Inflamação/complicações , Melanoma/complicações , Melanoma/diagnóstico , Melanoma/patologia , Neoplasias Uveais/complicações , Neoplasias Uveais/diagnóstico , Neoplasias Uveais/patologia
7.
Ophthalmic Plast Reconstr Surg ; 38(2): e44-e47, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34798653

RESUMO

Adenoid cystic carcinoma of the lacrimal gland is an aggressive, malignant epithelial neoplasm. We report the case of a 30-year-old male with lacrimal gland adenoid cystic carcinoma treated with neoadjuvant intra-arterial chemotherapy through the internal carotid artery, followed by orbital exenteration and chemoradiation. Treatment response was evaluated using a novel combination of pre- and posttreatment genome sequencing coupled with immunohistochemical evaluation, which showed diffuse tumor apoptosis. A posttreatment decrease in variant allele frequency of the NOTCH1 mutation, and robust tumor cytoreduction on imaging, supports exploration of NOTCH1 analysis as a potential marker of cisplatin sensitivity. The use of genome sequencing and immunohistochemical evaluation could provide a more targeted therapeutic assessment of neoadjuvant intra-arterial chemotherapy in the management of lacrimal gland adenoid cystic carcinoma.


Assuntos
Carcinoma Adenoide Cístico , Neoplasias Oculares , Doenças do Aparelho Lacrimal , Aparelho Lacrimal , Adulto , Carcinoma Adenoide Cístico/diagnóstico , Carcinoma Adenoide Cístico/tratamento farmacológico , Carcinoma Adenoide Cístico/genética , Procedimentos Cirúrgicos de Citorredução , Neoplasias Oculares/diagnóstico , Neoplasias Oculares/tratamento farmacológico , Neoplasias Oculares/genética , Humanos , Aparelho Lacrimal/patologia , Doenças do Aparelho Lacrimal/diagnóstico , Doenças do Aparelho Lacrimal/tratamento farmacológico , Doenças do Aparelho Lacrimal/patologia , Masculino
8.
J Biol Chem ; 295(1): 237-249, 2020 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-31792031

RESUMO

Endoplasmic reticulum (ER) stress activates the unfolded protein response (UPR), which reduces levels of misfolded proteins. However, if ER homeostasis is not restored and the UPR remains chronically activated, cells undergo apoptosis. The UPR regulator, PKR-like endoplasmic reticulum kinase (PERK), plays an important role in promoting cell death when persistently activated; however, the underlying mechanisms are poorly understood. Here, we profiled the microRNA (miRNA) transcriptome in human cells exposed to ER stress and identified miRNAs that are selectively induced by PERK signaling. We found that expression of a PERK-induced miRNA, miR-483, promotes apoptosis in human cells. miR-483 induction was mediated by a transcription factor downstream of PERK, activating transcription factor 4 (ATF4), but not by the CHOP transcription factor. We identified the creatine kinase brain-type (CKB) gene, encoding an enzyme that maintains cellular ATP reserves through phosphocreatine production, as being repressed during the UPR and targeted by miR-483. We found that ER stress, selective PERK activation, and CKB knockdown all decrease cellular ATP levels, leading to increased vulnerability to ER stress-induced cell death. Our findings identify miR-483 as a downstream target of the PERK branch of the UPR. We propose that disruption of cellular ATP homeostasis through miR-483-mediated CKB silencing promotes ER stress-induced apoptosis.


Assuntos
Trifosfato de Adenosina/metabolismo , MicroRNAs/metabolismo , Resposta a Proteínas não Dobradas , eIF-2 Quinase/metabolismo , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Apoptose , Creatina Quinase Forma BB/genética , Creatina Quinase Forma BB/metabolismo , Células HEK293 , Células HeLa , Homeostase , Humanos , MicroRNAs/genética , eIF-2 Quinase/genética
9.
Ophthalmic Plast Reconstr Surg ; 37(1): e21-e23, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32427738

RESUMO

Radiation-induced malignancy is rare, occurring in approximately 0.4%-1.0% of patients receiving external beam radiation therapy. Sarcomas and squamous cell carcinomas are among the most common types of cancers to occur. A 74-year-old woman presented with redness and swelling in the right periorbital region. She had history of multiple recurrent ameloblastoma of the right maxilla, invading the right orbital floor status post 4 surgical resections and 66 Gray external beam radiotherapy 5 years prior. MRI showed a poorly circumscribed mass involving the inferior and lateral orbit. Orbital biopsy revealed clear cell carcinoma with hyalinizing sclerosis and Ewing sarcoma breakpoint region 1 gene arrangement. Due to the extent of orbital disease and presence of perineural invasion, she underwent orbital exenteration. Hyalinizing clear cell carcinoma, a rare cancer, has not been reported to occur in the orbit following radiation. This case highlights the importance of lifetime monitoring in patients who have undergone radiation therapy.


Assuntos
Carcinoma de Células Escamosas , Doenças Orbitárias , Neoplasias Orbitárias , Idoso , Carcinoma de Células Escamosas/cirurgia , Feminino , Humanos , Órbita/diagnóstico por imagem , Exenteração Orbitária , Neoplasias Orbitárias/diagnóstico , Neoplasias Orbitárias/radioterapia , Neoplasias Orbitárias/cirurgia
10.
Ophthalmic Plast Reconstr Surg ; 37(3S): S152-S154, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32976332

RESUMO

The authors report an unusual case of lung adenocarcinoma metastasis to the lacrimal sac. A 61-year-old woman with stage IV non-small cell lung cancer presented with left facial pain and epiphora. She was found to have an elevated tear meniscus associated with a firm, fixed medial canthal mass. Orbital imaging demonstrated nodular enlargement of the lacrimal drainage apparatus. Biopsy of the lacrimal sac was performed, and it revealed a metastatic lung adenocarcinoma. The patient received targeted radiation therapy to the lacrimal sac, and her dose of maintenance chemotherapy was increased. The patient's symptoms have since improved. This case of lung cancer involving the lacrimal sac highlights the importance of thorough oncologic surveillance, even with respect to locations atypical for metastatic spread.


Assuntos
Adenocarcinoma de Pulmão , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Oculares , Doenças do Aparelho Lacrimal , Aparelho Lacrimal , Neoplasias Pulmonares , Ducto Nasolacrimal , Feminino , Humanos , Doenças do Aparelho Lacrimal/diagnóstico , Pessoa de Meia-Idade
11.
Orbit ; 40(4): 338-341, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32643502

RESUMO

An 84-year-old male with previously documented poor medical follow-up presented with progressive painless proptosis of the right eye. Right upper eyelid ptosis, limited motility, proptosis, and inferomedial displacement of the right globe were noted on the exam. Computed tomography (CT) imaging revealed a right retrobulbar extraconal heterogenous mass with ill-defined borders. Biopsy revealed a malignant adenocarcinoma with tumor markers suggestive of a colorectal primary. A rectal mass was identified during a systemic workup. After biopsy, the patient was diagnosed with stage IV metastatic rectal adenocarcinoma. He began palliative radiation therapy shortly following diagnosis.


Assuntos
Neoplasias Colorretais , Exoftalmia , Neoplasias Orbitárias , Idoso de 80 Anos ou mais , Humanos , Masculino , Órbita , Neoplasias Orbitárias/diagnóstico por imagem , Neoplasias Orbitárias/radioterapia , Tomografia Computadorizada por Raios X
12.
Hum Mol Genet ; 27(22): 3951-3963, 2018 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-30137327

RESUMO

Tauopathies are neurodegenerative diseases characterized by tau protein pathology in the nervous system. EIF2AK3 (eukaryotic translation initiation factor 2 alpha kinase 3), also known as PERK (protein kinase R-like endoplasmic reticulum kinase), was identified by genome-wide association study as a genetic risk factor in several tauopathies. PERK is a key regulator of the Unfolded Protein Response (UPR), an intracellular signal transduction mechanism that protects cells from endoplasmic reticulum (ER) stress. PERK variants had previously been identified in Wolcott-Rallison Syndrome, a rare autosomal recessive metabolic disorder, and these variants completely abrogated the function of PERK's kinase domain or prevented PERK expression. In contrast, the PERK tauopathy risk variants were distinct from the Wolcott-Rallison variants and introduced missense alterations throughout the PERK protein. The function of PERK tauopathy variants and their effects on neurodegeneration are unknown. Here, we discovered that tauopathy-associated PERK alleles showed reduced signaling activity and increased PERK protein turnover compared to protective PERK alleles. We found that iPSC-derived neurons carrying PERK risk alleles were highly vulnerable to ER stress-induced injury with increased tau pathology. We found that chemical inhibition of PERK in human iPSC-derived neurons also increased neuronal cell death in response to ER stress. Our results indicate that tauopathy-associated PERK alleles are functional hypomorphs during the UPR. We propose that reduced PERK function leads to neurodegeneration by increasing neuronal vulnerability to ER stress-associated damage. In this view, therapies to enhance PERK signaling would benefit at-risk carriers of hypomorphic alleles.


Assuntos
Estresse do Retículo Endoplasmático/genética , Tauopatias/genética , eIF-2 Quinase/genética , Alelos , Animais , Apoptose/genética , Diferenciação Celular/genética , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/patologia , Retículo Endoplasmático/genética , Epífises/anormalidades , Epífises/patologia , Fibroblastos/metabolismo , Fibroblastos/patologia , Regulação da Expressão Gênica/genética , Humanos , Camundongos , Mutação de Sentido Incorreto/genética , Degeneração Neural/genética , Degeneração Neural/patologia , Neurônios/metabolismo , Neurônios/patologia , Osteocondrodisplasias/genética , Osteocondrodisplasias/patologia , Polimorfismo de Nucleotídeo Único , Proteólise , Transdução de Sinais/genética , Tauopatias/patologia , Resposta a Proteínas não Dobradas/genética
13.
J Vasc Surg ; 72(1): 268-275, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31980248

RESUMO

OBJECTIVE: Studies evaluating major amputation after initial minor amputation are few with rates of subsequent major amputation ranging from 14% to 35% with limited understanding of associated comorbidities and time to limb loss. The aim of this study is to determine the major amputation rates for patients who had already undergone an initial minor amputation and determine which factors are associated with the need for subsequent major amputation. METHODS: Using statewide data between 2005 and 2013, patients with peripheral artery disease (PAD), diabetes mellitus (DM), and combined PAD/DM who had a lower extremity ulcer and who had also undergone a minor amputation were identified. These patients were evaluated for the rate of subsequent major amputation and competing risk Cox proportional hazards modeling was used to study which factors were associated with the risk of subsequent limb loss. RESULTS: The cohort consisted of 11,597 patients (DM, n = 4254; PAD, n = 2142; PAD/DM, n = 5201) with lower extremity ulcers who underwent an initial minor amputation. The rate of any subsequent amputation was highest in patients with PAD/DM (23% vs DM = 17%, PAD = 17%; P = not statistically significant). The rate of subsequent minor amputation was 16% in the PAD/DM versus 15.2% in PAD and 12.2% in patients with DM (P < .001). Patients with PAD/DM had the highest rate of subsequent major amputation (6.3% vs DM = 5.2%, PAD = 2.1%; P < .001). There was no statistically significant difference in the median time to major amputation among the three groups (PAD/DM, 13 months; DM, 14 months; PAD, 8.6 months; P = NS). Patients who were revascularized before a repeat minor amputation had a decreased risk of a major amputation compared with those who were intervened on after a repeat minor amputation (hazard ratio, 0.002; 95% confidence interval, 0-0.22). Patients treated completely in the outpatient setting were also less likely to undergo subsequent major amputation (hazard ratio, 0.7; 95% confidence interval, 0.5-0.98) compared with those who required hospitalization or presented to the emergency room. CONCLUSIONS: Patients with ulcers and combined PAD and DM have a higher risk for secondary major and minor amputation than patients with either disease alone with half of the limb loss occurring at approximately 1 year after the initial minor amputation. Additionally, early diagnosis and appropriate referral may result in decreased limb loss for these patients.


Assuntos
Amputação Cirúrgica/tendências , Angiopatias Diabéticas/cirurgia , Úlcera da Perna/cirurgia , Doença Arterial Periférica/cirurgia , Reoperação/tendências , Tempo para o Tratamento/tendências , Idoso , Idoso de 80 Anos ou mais , Amputação Cirúrgica/efeitos adversos , California , Bases de Dados Factuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reoperação/efeitos adversos , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
14.
Retina ; 40(11): 2216-2220, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32032254

RESUMO

PURPOSE: Uveal melanomas are associated with characteristic genetic changes. Germline mutations in mismatch repair (MMR) genes and microsatellite instability have been implicated in the development of numerous malignant neoplasms such as colon and ovarian cancers. The frequency of MMR defects in uveal melanomas has yet to be determined. METHODS: Here, we analyzed the frequency of MMR gene mutations in uveal melanoma specimens from the University of California, San Diego (UCSD), The Cancer Genome Atlas (TGCA), and the Catalogue of Somatic Mutations in Cancer (COSMIC). RESULTS: We identified only two mutations in a MMR gene: one premature stop codon in the PMS gene within the UCSD cohort (0.5% frequency) and one in-frame deletion in MSH3 within the COSMIC database (0.8% frequency). We report copy number variation of MLH1 in monosomy 3 and show decreased mRNA expression of MLH1 in uveal melanoma specimens with monosomy 3. Expression levels of MLH1 were not found to correlate with the observed number of total mutations. CONCLUSION: Overall, we show that mutations in MMR genes in uveal melanoma specimens are exceedingly rare, and although one copy of MLH1 is lost in monosomy 3, it does not seem to have pathologic consequences in uveal melanoma pathogenesis.


Assuntos
Reparo de Erro de Pareamento de DNA/genética , Melanoma/genética , Proteína 1 Homóloga a MutL/genética , Mutação/genética , Neoplasias Uveais/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Cromossomos Humanos Par 3/genética , Variações do Número de Cópias de DNA , DNA de Neoplasias/genética , Feminino , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Monossomia/genética , Prevalência , RNA Mensageiro/genética
15.
Proc Natl Acad Sci U S A ; 114(2): 400-405, 2017 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-28028229

RESUMO

Achromatopsia is an autosomal recessive disorder characterized by cone photoreceptor dysfunction. We recently identified activating transcription factor 6 (ATF6) as a genetic cause of achromatopsia. ATF6 is a key regulator of the unfolded protein response. In response to endoplasmic reticulum (ER) stress, ATF6 migrates from the ER to Golgi to undergo regulated intramembrane proteolysis to release a cytosolic domain containing a basic leucine zipper (bZIP) transcriptional activator. The cleaved ATF6 fragment migrates to the nucleus to transcriptionally up-regulate protein-folding enzymes and chaperones. ATF6 mutations in patients with achromatopsia include missense, nonsense, splice site, and single-nucleotide deletion or duplication changes found across the entire gene. Here, we comprehensively tested the function of achromatopsia-associated ATF6 mutations and found that they group into three distinct molecular pathomechanisms: class 1 ATF6 mutants show impaired ER-to-Golgi trafficking and diminished regulated intramembrane proteolysis and transcriptional activity; class 2 ATF6 mutants bear the entire ATF6 cytosolic domain with fully intact transcriptional activity and constitutive induction of downstream target genes, even in the absence of ER stress; and class 3 ATF6 mutants have complete loss of transcriptional activity because of absent or defective bZIP domains. Primary fibroblasts from patients with class 1 or class 3 ATF6 mutations show increased cell death in response to ER stress. Our findings reveal that human ATF6 mutations interrupt distinct sequential steps of the ATF6 activation mechanism. We suggest that increased susceptibility to ER stress-induced damage during retinal development underlies the pathology of achromatopsia in patients with ATF6 mutations.


Assuntos
Fator 6 Ativador da Transcrição/metabolismo , Defeitos da Visão Cromática/genética , Defeitos da Visão Cromática/metabolismo , Mutação/genética , Morte Celular/genética , Linhagem Celular , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/genética , Fibroblastos/metabolismo , Complexo de Golgi/metabolismo , Células HEK293 , Humanos , Chaperonas Moleculares/metabolismo , Transcrição Gênica/genética
16.
Adv Exp Med Biol ; 1185: 305-310, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31884629

RESUMO

Activating transcription factor 6 (ATF6) is a key regulator of the unfolded protein response (UPR). In response to endoplasmic reticulum (ER) stress, ATF6 is transported from the ER to the Golgi apparatus where it is cleaved by intramembrane proteolysis, releasing its cytosolic fragment. The cleaved ATF6 fragment, which is a basic leucine zipper (bZip) transcription factor, translocates to the nucleus and upregulates the expression of ER protein-folding chaperones and enzymes. Mutations in ATF6 cause heritable forms of cone photoreceptor dysfunction diseases. These mutations include missense, nonsense, splice site, and deletion or duplication changes found across the entire ATF6. To date, there are 11 ATF6 mutations reported, and we classified them into three classes based on their functional defects that interrupt distinct steps in the ATF6 signaling pathway.


Assuntos
Fator 6 Ativador da Transcrição/metabolismo , Células Fotorreceptoras Retinianas Cones/patologia , Transdução de Sinais , Estresse do Retículo Endoplasmático , Complexo de Golgi , Humanos , Mutação , Dobramento de Proteína
17.
Orbit ; 38(6): 492-494, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30628515

RESUMO

A 5-year-old otherwise healthy girl presented to the oculoplastic service with a painless superotemporal subconjunctival mass in the left eye. Visual acuity was within normal limits, and there was no evidence of proptosis or orbital enlargement. Excision was performed to remove the anterior portion of the mass for alleviation of symptoms. On histopathological analysis, the mass was comprised of fibroadipose tissue consistent with dermolipoma and contained a hard nodule found to be a calcified tooth. In the periocular region, odontogenic choristoma (tooth) is a rare lesion, and has been reported to occur within teratomas, dermoid cysts, and displaced oral embryonic epithelium. We describe an unusual case of a tooth occurring within a sporadic dermolipoma. The clinical presentation, examination, management, and histopathology are reviewed.


Assuntos
Coristoma/patologia , Doenças da Túnica Conjuntiva/patologia , Lipoma/patologia , Neoplasias Cutâneas/patologia , Dente , Pré-Escolar , Coristoma/cirurgia , Doenças da Túnica Conjuntiva/cirurgia , Feminino , Humanos , Lipoma/cirurgia , Procedimentos Cirúrgicos Oftalmológicos , Neoplasias Cutâneas/cirurgia
18.
Orbit ; 37(3): 187-190, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29072521

RESUMO

Enophthalmos in the setting of breast cancer metastatic to the orbit results primarily from the disease pathogenesis, or secondary to treatment effects. Orbital volume restoration and fat regeneration following endocrine treatment monotherapy has not been previously reported. A 76- year-old previously healthy female presented with progressive right enophthalmos secondary to metastatic lobular breast carcinoma. Treatment with an aromatase inhibitor (letrozole) resulted in tumor regression and orbital fat restoration with a corresponding improvement in orbital volume and enophthalmos on clinical exam. The patient is alive on continued letrozole with no progressive disease ten years after diagnosis. This case illustrates the resilience of orbital soft tissues and ability of orbital fat to regenerate in face of breast cancer metastasis. We hypothesize that endocrine monotherapy, and avoidance of radiation therapy, allowed for differentiation of remaining orbital stem cells, and facilitated the fat regenerative process.


Assuntos
Tecido Adiposo/fisiologia , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Carcinoma Lobular/tratamento farmacológico , Enoftalmia/etiologia , Nitrilas/uso terapêutico , Órbita/fisiologia , Neoplasias Orbitárias/tratamento farmacológico , Regeneração/fisiologia , Triazóis/uso terapêutico , Idoso , Antineoplásicos/uso terapêutico , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Carcinoma Lobular/diagnóstico por imagem , Carcinoma Lobular/secundário , Enoftalmia/diagnóstico por imagem , Enoftalmia/fisiopatologia , Feminino , Humanos , Letrozol , Neoplasias Orbitárias/diagnóstico por imagem , Neoplasias Orbitárias/secundário , Tomografia Computadorizada por Raios X
19.
Physiol Genomics ; 49(4): 216-229, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28130426

RESUMO

Our purpose was to identify causative mutations and characterize the phenotype associated with the genotype in 10 unrelated families with autosomal recessive retinal degeneration. Ophthalmic evaluation and DNA isolation were carried out in 10 pedigrees with inherited retinal degenerations (IRD). Exomes of probands from eight pedigrees were captured using Nimblegen V2/V3 or Agilent V5+UTR kits, and sequencing was performed on Illumina HiSeq. The DHDDS gene was screened for mutations in the remaining two pedigrees with Ashkenazi Jewish ancestry. Exome variants were filtered to detect candidate causal variants using exomeSuite software. Segregation and ethnicity-matched control sample analysis were performed by dideoxy sequencing. Retinal histology of a patient with DHDDS mutation was studied by microscopy. Genetic analysis identified six known mutations in ABCA4 (p.Gly1961Glu, p.Ala1773Val, c.5461-10T>C), RPE65 (p.Tyr249Cys, p.Gly484Asp), PDE6B (p.Lys706Ter) and DHDDS (p.Lys42Glu) and ten novel potentially pathogenic variants in CERKL (p.Met323Val fsX20), RPE65 (p.Phe252Ser, Thr454Leu fsX31), ARL6 (p.Arg121His), USH2A (p.Gly3142Ter, p.Cys3294Trp), PDE6B (p.Gln652Ter), and DHDDS (p.Thr206Ala) genes. Among these, variants/mutations in two separate genes were observed to segregate with IRD in two pedigrees. Retinal histopathology of a patient with a DHDDS mutation showed severe degeneration of retinal layers with relative preservation of the retinal pigment epithelium. Analysis of exome variants in ten pedigrees revealed nine novel potential disease-causing variants and nine previously reported homozygous or compound heterozygous mutations in the CERKL, ABCA4, RPE65, ARL6, USH2A, PDE6B, and DHDDS genes. Mutations that could be sufficient to cause pathology were observed in more than one gene in one pedigree.


Assuntos
Exoma/genética , Genótipo , Fenótipo , Degeneração Retiniana/genética , Fatores de Ribosilação do ADP/genética , Transportadores de Cassetes de Ligação de ATP/genética , Alquil e Aril Transferases/genética , Análise Mutacional de DNA , Feminino , Estudos de Associação Genética , Humanos , Masculino , Mutação/genética , Linhagem , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Síndromes de Usher/genética , cis-trans-Isomerases/genética
20.
RNA ; 21(6): 1122-34, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25904139

RESUMO

Head and neck squamous cell carcinoma persists as one of the most common and deadly malignancies, with early detection and effective treatment still posing formidable challenges. To expand our currently sparse knowledge of the noncoding alterations involved in the disease and identify potential biomarkers and therapeutic targets, we globally profiled the dysregulation of small nucleolar and long noncoding RNAs in head and neck tumors. Using next-generation RNA-sequencing data from 40 pairs of tumor and matched normal tissues, we found 2808 long noncoding RNA (lncRNA) transcripts significantly differentially expressed by a fold change magnitude ≥2. Meanwhile, RNA-sequencing analysis of 31 tumor-normal pairs yielded 33 significantly dysregulated small nucleolar RNAs (snoRNA). In particular, we identified two dramatically down-regulated lncRNAs and one down-regulated snoRNA whose expression levels correlated significantly with overall patient survival, suggesting their functional significance and clinical relevance in head and neck cancer pathogenesis. We confirmed the dysregulation of these noncoding RNAs in head and neck cancer cell lines derived from different anatomic sites, and determined that ectopic expression of the two lncRNAs inhibited key EMT and stem cell genes and reduced cellular proliferation and migration. As a whole, noncoding RNAs are pervasively dysregulated in head and squamous cell carcinoma. The precise molecular roles of the three transcripts identified warrants further characterization, but our data suggest that they are likely to play substantial roles in head and neck cancer pathogenesis and are significantly associated with patient survival.


Assuntos
Carcinoma de Células Escamosas/genética , Perfilação da Expressão Gênica/métodos , Neoplasias de Cabeça e Pescoço/genética , RNA Longo não Codificante/genética , RNA Nucleolar Pequeno/genética , Análise de Sequência de RNA/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Transição Epitelial-Mesenquimal , Feminino , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/patologia , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sobrevida
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