RESUMEN
Pettigrew syndrome (PGS), an X-linked intellectual disability (XLID), is caused by mutations in the AP1S2 gene. Herein, we described a Thai family with six patients who had severe-to-profound intellectual impairment, limited verbal communication, and varying degrees of limb spasticity. One patient had a unilateral cataract. We demonstrated facial evolution over time, namely coarse facies, long faces, and thick lip vermilions. We identified a novel AP1S2 variant, c.1-2A>G. The mRNA analysis revealed that the variant resulted in splicing defects with leaky splicing, yielding two distinct aberrant transcripts, one of which likely resulting in the mutant protein lacking the first 44 amino acids whereas the other possibly leading to no production of the protein. By performing a literature review, we found 51 patients and 11 AP1S2 pathogenic alleles described and that all the variants were loss-of-function alleles. The severity of ID in Pettigrew syndrome is mostly severe-to-profound (54.8%), followed by moderate (26.2%) and mild. Progressive spasticity was noted in multiple patients. In summary, leaky splicing found in the present family was likely related to the intrafamilial clinical variability. Our data also support the previous notion of variable expression and neuroprogressive nature of the disorder.
Asunto(s)
Discapacidad Intelectual , Linaje , Empalme del ARN , Humanos , Masculino , Empalme del ARN/genética , Femenino , Discapacidad Intelectual/genética , Discapacidad Intelectual/patología , Niño , Discapacidad Intelectual Ligada al Cromosoma X/genética , Discapacidad Intelectual Ligada al Cromosoma X/patología , Adulto , Mutación/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Alelos , Adolescente , Preescolar , FenotipoRESUMEN
MiR-204-5p, as a tumour suppressor, has been found in several cancers. However, whether miR-204-5p is involved in papillary thyroid carcinoma (PTC) has not yet been investigated. In this study, we identified miR-204-5p as a down-regulated miRNA in PTC tissues, unveiling that the levels of miR-204-5p in serum of patients with PTC were linked to PTC risk, and that the expression in patients concomitant with both PTC and benign lesions was much lower than that in patients only with PTC. Furthermore, we documented that miR-204-5p inhibited proliferation, migration, invasion, and cell cycle progression and triggered apoptosis of PTC cells via cell biology experiments. Finally, we identified that AP1S2 was a target of miR-204-5p using RNA-seq, iTRAQ, and bioinformatics prediction. Overall, miR-204-5p functions as a suppressor for PTC pathogenesis via the miR-204-5p/AP1S2 axis.
Asunto(s)
Subunidades sigma de Complejo de Proteína Adaptadora , MicroARNs , Neoplasias de la Tiroides , Humanos , Cáncer Papilar Tiroideo/patología , Neoplasias de la Tiroides/patología , Línea Celular Tumoral , Proliferación Celular/genética , MicroARNs/genética , MicroARNs/metabolismo , Regulación Neoplásica de la Expresión Génica , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/metabolismoRESUMEN
Inherited syndromes of congenital enteropathy are rare, with many genetic causes described. Mutations of the AP1S1 gene results in the syndrome of intellectual disability, enteropathy, deafness, peripheral neuropathy, ichthyosis, and keratoderma (IDEDNIK, formerly in the medical literature as MEDNIK). The clinicopathologic features of the enteropathy in IDEDNIK syndrome have not been fully explored. We describe a female infant who presented with metabolic acidosis, lethargy, and 14 watery stools per day. In the intensive care unit she required parenteral nutrition. She was found to have a novel homozygous pathogenic variant in the AP1S1 gene c.186T>G (p.Y62*). Esophagogastroduodenoscopy and colonoscopy at 6 months of age were grossly normal. However, histologic sections of the duodenum showed mild villous blunting and enterocytes with cytoplasmic vacuoles. CD10 immunostaining highlighted the disrupted brush border. MOC31 immunostaining was wild-type with a membranous pattern of expression. Electron microscopy of the duodenum showed scattered enterocytes cells with shortened and disrupted apical microvilli. Although there is a mixed gap diarrhea and disrupted brush border, there are no significant inclusions typical of microvillus inclusion disease, nor tufted enterocytes typical of tufting enteropathy, making the clinical and histopathologic features for this syndrome unique.
Asunto(s)
Subunidades sigma de Complejo de Proteína Adaptadora , Síndromes de Malabsorción , Femenino , Humanos , Lactante , Complejo 1 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Diarrea/genética , Duodeno , Síndromes de Malabsorción/diagnóstico , Síndromes de Malabsorción/genética , Síndromes de Malabsorción/metabolismo , Mutación , SíndromeRESUMEN
Adaptor-related protein complex 1 subunit sigma 2 (AP1S2) is a subunit of AP1 that is crucial for the reformation of the synaptic vesicle. Variants in AP1S2 have been reported to cause a rare neurodevelopmental disorder, Pettigrew syndrome (PGS) (OMIM: 304,340), which is characterized by walking delay, abnormal speech, mild to profound X-linked intellectual disability (XLID), and abnormal brain, and behaviors. Here, we describe a 2-year- and 5-month-old male patient who presented with global developmental delay (GDD). Trio whole exome sequencing (WES) revealed a 5 bp duplicate in the AP1S2 gene (NM_003916.5: exon 2: c.96_100dup, p. Leu34Glnfs*8) predicted to cause early termination of translation, which was inherited from the unaffected mother. The clinical features of our patient were consistent with previous reports. This is the second case in the Chinese family and the eleventh variant found in AP1S2-related XLID. Our findings expand the AP1S2 variant spectrum in neurodevelopmental disorders and provide evidence for the application of WES in PGS diagnosis.
Asunto(s)
Subunidades sigma de Complejo de Proteína Adaptadora , Discapacidad Intelectual , Discapacidad Intelectual Ligada al Cromosoma X , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Enfermedades de los Ganglios Basales , Síndrome de Dandy-Walker , Genes Ligados a X , Humanos , Discapacidad Intelectual/diagnóstico , Discapacidad Intelectual/genética , Masculino , Discapacidad Intelectual Ligada al Cromosoma X/genética , Linaje , ConvulsionesRESUMEN
Adaptor protein 2 (AP2), a heterotetrameric complex comprising AP2α, AP2ß2, AP2µ2 and AP2σ2 subunits, is ubiquitously expressed and involved in endocytosis and trafficking of membrane proteins, such as the calcium-sensing receptor (CaSR), a G-protein coupled receptor that signals via Gα11. Mutations of CaSR, Gα11 and AP2σ2, encoded by AP2S1, cause familial hypocalciuric hypercalcaemia types 1-3 (FHH1-3), respectively. FHH3 patients have heterozygous AP2S1 missense Arg15 mutations (p.Arg15Cys, p.Arg15His or p.Arg15Leu) with hypercalcaemia, which may be marked and symptomatic, and occasional hypophosphataemia and osteomalacia. To further characterize the phenotypic spectrum and calcitropic pathophysiology of FHH3, we used CRISPR/Cas9 genome editing to generate mice harboring the AP2S1 p.Arg15Leu mutation, which causes the most severe FHH3 phenotype. Heterozygous (Ap2s1+/L15) mice were viable, and had marked hypercalcaemia, hypermagnesaemia, hypophosphataemia, and increases in alkaline phosphatase activity and fibroblast growth factor-23. Plasma 1,25-dihydroxyvitamin D was normal, and no alterations in bone mineral density or bone turnover were noted. Homozygous (Ap2s1L15/L15) mice invariably died perinatally. Co-immunoprecipitation studies showed that the AP2S1 p.Arg15Leu mutation impaired protein-protein interactions between AP2σ2 and the other AP2 subunits, and also with the CaSR. Cinacalcet, a CaSR positive allosteric modulator, decreased plasma calcium and parathyroid hormone concentrations in Ap2s1+/L15 mice, but had no effect on the diminished AP2σ2-CaSR interaction in vitro. Thus, our studies have established a mouse model that is representative for FHH3 in humans, and demonstrated that the AP2S1 p.Arg15Leu mutation causes a predominantly calcitropic phenotype, which can be ameliorated by treatment with cinacalcet.
Asunto(s)
Complejo 2 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Factor-23 de Crecimiento de Fibroblastos/genética , Hipercalcemia/genética , Receptores Sensibles al Calcio/genética , Animales , Densidad Ósea/genética , Sistemas CRISPR-Cas/genética , Calcio/metabolismo , Cinacalcet/farmacología , Modelos Animales de Enfermedad , Edición Génica , Humanos , Hipercalcemia/tratamiento farmacológico , Hipercalcemia/metabolismo , Hipercalcemia/patología , Ratones , Mutación/genética , FenotipoRESUMEN
BACKGROUND: Familial hypocalciuric hypercalcemia (FHH) is a heterogeneous autosomal-dominant disorder of calcium hemostasis that may be difficult to distinguish clinically from mild primary hyperparathyroidism. Loss-of-function mutations mainly involving Arg15 residue of the adaptor-related protein complex 2, sigma subunit 1 (AP2S1) cause a rarer, more recently recognized form of FHH, FFH type-3. Recently, 18F-fluorocholine positron emission tomography/computed tomography (FCH-PET/CT) showed superior sensitivity to conventional imaging in localizing parathyroid adenomas. We report a new FFH type-3 patient who underwent unnecessary parathyroidectomy in association with misleading FCH-PET/CT imaging. CASE PRESENTATION: A 29-year old woman was initially evaluated for parathyroid hormone (PTH)-dependent hypercalcemia in 2013. Medical history was positive only for chronic constipation and malaise with no personal or family history of hypercalcemia, kidney stones, or neck surgery. Over seven years, serum calcium level was 2.51-2.89 mmol/L with concomitant PTH level of 58.7-94.8 mmol/L. Serum phosphate levels were in the low/low normal range. Serum creatinine and magnesium levels were normal. 25-hydroxy vitamin D level was 13 nmol/L. 24-hour urine calcium level was 1.92 mmol/day but increased to 6.99 mmol/day after treatment with cholecalciferol 1000 IU daily. Bone mineral density and renal ultrasound were normal. Parathyroid ultrasound showed two hypoechoic nodules inferior to the left and right thyroid lobes; however, 99mtechnitium-sestamibi scans (2013, 2016, 2018) were negative. FCH-PET/CT (2019) showed focal uptake co-localizing with the nodule inferior to the left thyroid lobe. The patient underwent left inferior parathyroidectomy and pathology was consistent with parathyroid hyperplasia. However, postoperatively, serum calcium and PTH levels remained elevated and FCH-PET/CT and ultrasound showed persistence of the uptake/nodule. Whole exome sequencing showed Arg15Cys mutation in the AP2S1 gene characteristic of FHH type-3. CONCLUSIONS: In this new case of FHH type-3, FCH-PET/CT failed to localize to the hyperplastic parathyroid glands and localized instead to apparently a lymph node. This, together with increased urinary calcium after vitamin D supplementation, led to unnecessary parathyroidectomy. Given the increasingly lower cost of genetic testing and the cost of follow up and unnecessary surgery, it may prudent to include genetic testing for FHH early on in patients with mild PTH-dependent hypercalcemia.
Asunto(s)
Calcio/orina , Colina/análogos & derivados , Hipercalcemia/congénito , Hipercalcemia/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Complejo 2 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Adulto , Densidad Ósea , Calcio/sangre , Femenino , Humanos , Hipercalcemia/genética , Hiperparatiroidismo Primario/complicaciones , Hiperparatiroidismo Primario/genética , Hiperparatiroidismo Primario/cirugía , Riñón/diagnóstico por imagen , Glándulas Paratiroides/diagnóstico por imagen , Hormona Paratiroidea/sangre , Paratiroidectomía , Radiofármacos , Resultado del TratamientoRESUMEN
A 45-year-old man was referred to endocrine for the evaluation of hypercalcaemia. The calcium was elevated, vitamin D was low with a normal parathyroid hormone. Dual-energy X-ray absorptiometry scan revealed osteoporosis at the lumbar spine and femoral neck. A 24-hour urine collection revealed low urinary calcium, which was believed to be secondary to vitamin D deficiency. A diagnosis of primary hyperparathyroidism was made. The patient underwent a four-gland parathyroid exploration surgery in which three of his parathyroid glands were removed. The pathology was consistent with benign parathyroid tissue. Post surgery, the patient had persistently elevated calcium levels. He was then started on bisphosphonate and cinacalcet for osteoporosis and hypercalcaemia, respectively. Genetic analysis of familial hypocalciuric hypercalcaemia (FHH) showed a p.arg15cys mutation in the AP2S1 gene, confirming the diagnosis of FHH type 3.
Asunto(s)
Complejo 2 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , ADN/genética , Hipercalcemia/congénito , Mutación Missense , Complejo 2 de Proteína Adaptadora/metabolismo , Subunidades sigma de Complejo de Proteína Adaptadora/metabolismo , Análisis Mutacional de ADN , Diagnóstico Diferencial , Humanos , Hipercalcemia/diagnóstico , Hipercalcemia/genética , Hipercalcemia/metabolismo , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Rayos X , UltrasonografíaRESUMEN
Congenital diarrheal disorders (CDD) comprise > 50 monogenic entities featuring chronic diarrhea of early-onset, including defects in nutrient and electrolyte absorption, enterocyte polarization, enteroendocrine cell differentiation, and epithelial integrity. Diarrhea is also a predominant symptom in many immunodeficiencies, congenital disorders of glycosylation, and in some defects of the vesicular sorting and transporting machinery. We set out to identify the etiology of an intractable diarrhea in 2 consanguineous families by whole-exome sequencing, and identified two novel AP1S1 mutations, c.269T>C (p.Leu90Pro) and c.346G>A (p.Glu116Lys). AP1S1 encodes the small subunit of the adaptor protein 1 complex (AP-1), which plays roles in clathrin coat-assembly and trafficking between trans-Golgi network, endosomes and the plasma membrane. An AP1S1 knock-out (KO) of a CaCo2 intestinal cell line was generated to characterize intestinal AP1S1 deficiency as well as identified mutations by stable expression in KO background. Morphology and prototype transporter protein distribution were comparable between parental and KO cells. We observed altered localization of tight-junction proteins ZO-1 and claudin 3, decreased transepithelial electrical resistance and an increased dextran permeability of the CaCo2-AP1S1-KO monolayer. In addition, lumen formation in 3D cultures of these cells was abnormal. Re-expression of wild-type AP1S1 in CaCo2-AP1S1-KO cells reverted these abnormalities, while expression of AP1S1 containing either missense mutation did not. Our data indicate that loss of AP1S1 function causes an intestinal epithelial barrier defect, and that AP1S1 mutations can cause a non-syndromic form of congenital diarrhea, whereas 2 reported truncating AP1S1 mutations caused MEDNIK syndrome, characterized by mental retardation, enteropathy, deafness, neuropathy, ichthyosis, and keratodermia.
Asunto(s)
Complejo 1 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Sordera/genética , Diarrea/genética , Ictiosis/genética , Discapacidad Intelectual/genética , Queratodermia Palmoplantar/genética , Mutación Missense , Complejo 1 de Proteína Adaptadora/deficiencia , Subunidades sigma de Complejo de Proteína Adaptadora/deficiencia , Secuencia de Bases , Células CACO-2 , Claudina-3/genética , Claudina-3/metabolismo , Consanguinidad , Sordera/diagnóstico , Sordera/metabolismo , Sordera/patología , Diarrea/diagnóstico , Diarrea/metabolismo , Diarrea/patología , Femenino , Expresión Génica , Técnicas de Inactivación de Genes , Prueba de Complementación Genética , Humanos , Ictiosis/diagnóstico , Ictiosis/metabolismo , Ictiosis/patología , Lactante , Recién Nacido , Discapacidad Intelectual/diagnóstico , Discapacidad Intelectual/metabolismo , Discapacidad Intelectual/patología , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Queratodermia Palmoplantar/diagnóstico , Queratodermia Palmoplantar/metabolismo , Queratodermia Palmoplantar/patología , Linaje , Permeabilidad , Secuenciación del Exoma , Proteína de la Zonula Occludens-1/genética , Proteína de la Zonula Occludens-1/metabolismoRESUMEN
Familial hypocalciuric hypercalcaemia (FHH) is a genetic disorder of altered calcium homeostasis. Mutations in the CASR, GNA11 and AP2S1 genes have been reported to cause FHH. We report a Hong Kong Chinese kindred with FHH type 3 (FHH3) caused by mutations in AP2S1. The proband, a 51-year-old woman with hypercalcaemia, was initially diagnosed to have primary hyperparathyroidism but repeated parathyroidectomy failed to normalize her plasma calcium concentrations. Later, FHH was suspected and yet no mutations were identified in the CASR gene which causes FHH type 1 (FHH1), the most common form of FHH. Genetic testing of AP2S1 revealed a heterozygous c.43C>T (p.Arg15Cys) mutation, confirming the diagnosis of FHH3. The elder brother and niece of the proband, who both have hypercalcaemia, were found to harbour the same mutation. To our knowledge, this is the first Chinese kindred of FHH3 reported in the English literature.
Asunto(s)
Complejo 2 de Proteína Adaptadora , Subunidades sigma de Complejo de Proteína Adaptadora , Hipercalcemia/congénito , Enfermedad Aguda , Complejo 2 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Anciano , Femenino , Hong Kong , Humanos , Hipercalcemia/genética , Masculino , Persona de Mediana Edad , MutaciónRESUMEN
Long intergenic nonprotein coding RNA 518 (LINC00518) has been shown to promote cancer cell growth and metastasis in some human tumors. Although it has been reported that LINC00518 is dysregulated in melanoma, its exact role and molecular mechanism in melanoma remain unclear. RNA-seq analysis and qRT-PCR was used to detect the expression of LINC00518 in melanoma tissues. Melanoma cases from The Cancer Genome Atlas (TCGA), GEO#GSE15605 and GEO#GSE24469 were included in this study. 3D migration, transwell and scratch wound assay were used to explore the role of LINC00518 in melanoma cells. Bioinformatics, luciferase reporter assays, MS2-RIP assay, RNA pull-down assay and RNA-ChIP assay were used to demonstrate the mechanism of LINC00518 in melanoma. We found that LICN00518 was significantly upregulated in melanoma tissue, and high LICN00518 level was an independent risk factor for melanoma patients. LICN00518 promoted the invasion and migration of melanoma cells. LICN00518 exerted its role by decoying miR-204-5p to upregulate Adaptor Related Protein Complex 1 Sigma 2 Subunit (AP1S2) expression. We also demonstrated that LICN00518 promoted melanoma metastasis in vivo through pulmonary metastasis assay. This result elucidates a new mechanism for LICN00518 in the metastasis of melanoma. LICN00518 may serve as a survival indicator and potential therapeutic target in melanoma patients.
Asunto(s)
Subunidades sigma de Complejo de Proteína Adaptadora/genética , Melanoma/genética , MicroARNs/genética , ARN Largo no Codificante/genética , Apoptosis/genética , Línea Celular Tumoral , Proliferación Celular/genética , Supervivencia sin Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Estimación de Kaplan-Meier , Masculino , Melanoma/patología , Persona de Mediana Edad , Metástasis de la NeoplasiaRESUMEN
Familial hypocalciuric hypercalcemia is an autosomal dominant genetic disorder characterized by hypercalcemia associated with inappropriate hypocalciuria and normal parathyroid hormone levels. Acute recurrent pancreatitis (ARP) is rare in children. Predisposing factors include hypercalcemia and mutations in the serine protease inhibitor Kazal-type 1 (SPINK1) gene. The disease carries a heavy morbidity and preventive treatment options are scant. Here, we report a child with a novel genetic/metabolic form of ARP associated with compound heterozygous SPINK1/AP2S1 (adaptor protein-2 σ1-subunit) mutations, recurrence of which was completely abrogated for 6 years by cinacalcet treatment.
Asunto(s)
Complejo 2 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Hormonas y Agentes Reguladores de Calcio/uso terapéutico , Cinacalcet/uso terapéutico , Pancreatitis/genética , Pancreatitis/prevención & control , Inhibidor de Tripsina Pancreática de Kazal/genética , Enfermedad Aguda , Adolescente , Femenino , Humanos , Hipercalcemia/complicaciones , Hipercalcemia/congénito , Hipercalcemia/genética , Mutación/genética , RecurrenciaRESUMEN
OBJECTIVE: Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominantly inherited disorder with overlapping biochemistry profile with primary hyperparathyroidism (PHPT), making the correct diagnosis a challenge. The objective of the study was to evaluate the results of the clinical work-up of a large group of hypercalcemic individuals. DESIGN: Cross-sectional study. PATIENTS: Patients undergoing clinical work-up of hypercalcemia. MEASUREMENTS: Molecular genetic analysis of the CASR gene and exon 2 of the AP2S1 gene. Plasma levels of ionized calcium and PTH as well as calcium creatinine clearance ratio (CCCR). RESULTS: A rare CASR variant was identified in 38 of 624 index patients (6.1%). A total of 18 CASR variants identified in this study were novel. No variants were identified in exon 2 of the AP2S1 gene. The majority of the variants (N = 16) were classified as likely pathogenic. The level of plasma calcium, plasma PTH and the CCCR was not affected by the type of variant (ie nonsense vs missense) (all P-values >.05). The CCCR was found to be significantly lower for variants in the transmembrane domain compared with variants located in the extracellular domain (P < .05). Plasma levels of calcium and PTH were not associated with the location of the variant (P > .05). CONCLUSIONS: We expanded the spectrum of CASR variants in hypercalcemia with 18 novel variants, and suggest that the location of the CASR variant may affect calcium excretion as determined by the CCCR.
Asunto(s)
Hipercalcemia/genética , Receptores Sensibles al Calcio/genética , Complejo 2 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Calcio/sangre , Estudios Transversales , Exones/genética , Humanos , Hipercalcemia/sangre , Hipercalcemia/congénito , Mutación/genética , Reacción en Cadena de la PolimerasaRESUMEN
BACKGROUND & AIMS: Hepatocyte polarity is essential for the development of bile canaliculi and for safely transporting bile and waste products from the liver. Functional studies of autologous mutated proteins in the context of the polarized hepatocyte have been challenging because of the lack of appropriate cell models. The aims of this study were to obtain a patient-specific hepatocyte model that recapitulated hepatocyte polarity and to employ this model to study endogenous mutant proteins in liver diseases that involve hepatocyte polarity. METHODS: Urine cell-derived pluripotent stem cells, taken from a patient with a homozygous mutation in ATP7B and a patient with a heterozygous mutation, were differentiated towards hepatocyte-like cells (hiHeps). HiHeps were also derived from a patient with MEDNIK syndrome. RESULTS: Polarized hiHeps that formed in vivo-like bile canaliculi could be generated from embryonic and patient urine cell-derived pluripotent stem cells. HiHeps recapitulated polarized protein trafficking processes, exemplified by the Cu2+-induced redistribution of the copper transporter protein ATP7B to the bile canalicular domain. We demonstrated that, in contrast to the current dogma, the most frequent yet enigmatic Wilson disease-causing ATP7B-H1069Q mutation per se did not preclude trafficking of ATP7B to the trans-Golgi Network. Instead, it prevented its Cu2+-induced polarized redistribution to the bile canalicular domain, which could not be reversed by pharmacological folding chaperones. Finally, we demonstrate that hiHeps from a patient with MEDNIK syndrome, suffering from liver copper overload of unclear etiology, showed no defect in the Cu2+-induced redistribution of ATP7B to the bile canaliculi. CONCLUSIONS: Functional cell polarity can be achieved in patient pluripotent stem cell-derived hiHeps, enabling, for the first time, the study of the endogenous mutant proteins, patient-specific pathogenesis and drug responses for diseases where hepatocyte polarity is a key factor. LAY SUMMARY: This study demonstrates that cells that are isolated from urine can be reprogrammed in a dish towards hepatocytes that display architectural characteristics similar to those seen in the intact liver. The application of this methodology to cells from patients diagnosed with inherited copper metabolism-related liver diseases (that is, Wilson disease and MEDNIK syndrome) revealed unexpected and novel insights into patient mutation-specific disease mechanisms and drug responses.
Asunto(s)
Canalículos Biliares/patología , Polaridad Celular/genética , Eritroqueratodermia Variable/genética , Hepatocitos/metabolismo , Degeneración Hepatolenticular/genética , Células Madre Pluripotentes/metabolismo , Complejo 1 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Canalículos Biliares/metabolismo , Células Cultivadas , Cobre/metabolismo , ATPasas Transportadoras de Cobre/genética , Eritroqueratodermia Variable/patología , Degeneración Hepatolenticular/patología , Humanos , Proteínas Mutantes/metabolismo , Mutación , Transporte de ProteínasRESUMEN
BACKGROUND: Pettigrew syndrome (PGS) is a rare X-linked mental retardation that caused by AP1S2 mutation. The pathogenesis of AP1S2 deficiency has remained elusive. The purpose of this study is to give a comprehensive overview of the phenotypic and genetic spectrum of AP1S2 mutations. METHODS: This study systematically analyzed clinical features and genetic information of a Chinese family with AP1S2 variation, and reviewed previously reported literatures with the same gene variation. RESULTS: We identified a new c.1-1 G>C mutation in AP1S2 gene from a four generation family with seven affected individuals and found the elevated neuron-specific enolase (NSE) in a patient. We summarized the clinical manifestation of 59 patients with AP1S2 mutation. We found that pathogenic point mutations affecting AP1S2 are associated with dysmorphic features and neurodevelopmental problems, which included highly variable mental retardation (MR), delayed in walking, abnormal speech, hypotonia, abnormal brain, abnormal behavior including aggressive behavior, ASD, self-abusive, and abnormal gait. Patients with splice site mutation were more likely to lead to seizures. By contrast, patients with nonsense mutations are more susceptible to microcephaly. CONCLUSION: Our findings suggest AP1S2 mutations contribute to a broad spectrum of neurodevelopmental disorders and are important in the etiological spectrum of PGS.
Asunto(s)
Subunidades sigma de Complejo de Proteína Adaptadora/genética , Enfermedades de los Ganglios Basales , Trastorno Dismórfico Corporal , Síndrome de Dandy-Walker , Discapacidad Intelectual Ligada al Cromosoma X , Trastornos del Neurodesarrollo , Convulsiones , Adulto , Enfermedades de los Ganglios Basales/complicaciones , Enfermedades de los Ganglios Basales/genética , Enfermedades de los Ganglios Basales/psicología , Trastorno Dismórfico Corporal/etiología , Trastorno Dismórfico Corporal/genética , Niño , Preescolar , Síndrome de Dandy-Walker/complicaciones , Síndrome de Dandy-Walker/genética , Síndrome de Dandy-Walker/psicología , Femenino , Humanos , Masculino , Discapacidad Intelectual Ligada al Cromosoma X/complicaciones , Discapacidad Intelectual Ligada al Cromosoma X/genética , Discapacidad Intelectual Ligada al Cromosoma X/psicología , Mutación , Trastornos del Neurodesarrollo/etiología , Trastornos del Neurodesarrollo/genética , Linaje , Fosfopiruvato Hidratasa/metabolismo , Convulsiones/complicaciones , Convulsiones/genética , Convulsiones/psicologíaRESUMEN
MEDNIK syndrome is an autosomal recessive rare disease as one of the most recently described copper metabolism disorder characterized by intellectual disability, ichthyosis, hearing loss, peripheral neuropathy, enteropathy and keratodermia. Here in, we reported a case presented with ichthyosis and intellectual disability with MEDNIK syndrome that confirmed by mutation analysis in a Turkish child. She was finally diagnosed with MEDNIK syndrome by clinical findings, which were confirmed by molecular genetic testing. Sequencing of AP1S1 gene showed a homozygous insertion c.364dupG (NM_001283.4), which is predicted to cause a frameshift of the reading frame (p.D122Gfs*18). To our knowledge, this is the first case of MEDNIK syndrome from Turkey. Diagnosis of MEDNIK syndrome is still challenging and we hope that this case will contribute to further understanding.
Asunto(s)
Complejo 1 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Cobre/metabolismo , Mutación del Sistema de Lectura/genética , Discapacidad Intelectual/genética , Discapacidad Intelectual/metabolismo , Niño , ATPasas Transportadoras de Cobre/genética , ATPasas Transportadoras de Cobre/metabolismo , Femenino , Humanos , Discapacidad Intelectual/diagnóstico , SíndromeRESUMEN
Mutations of the sigma subunit of the heterotetrameric adaptor-related protein complex 2 (AP2σ) impair signalling of the calcium-sensing receptor (CaSR), and cause familial hypocalciuric hypercalcaemia type 3 (FHH3). To date, FHH3-associated AP2σ mutations have only been identified at one residue, Arg15. We hypothesized that additional rare AP2σ variants may also be associated with altered CaSR function and hypercalcaemia, and sought for these by analysing >111 995 exomes (>60 706 from ExAc and dbSNP, and 51 289 from the Geisinger Health System-Regeneron DiscovEHR dataset, which also contains clinical data). This identified 11 individuals to have 9 non-synonymous AP2σ variants (Arg3His, Arg15His (x3), Ala44Thr, Phe52Tyr, Arg61His, Thr112Met, Met117Ile, Glu122Gly and Glu142Lys) with 3 of the 4 individuals who had Arg15His and Met117Ile AP2σ variants having mild hypercalcaemia, thereby indicating a prevalence of FHH3-associated AP2σ mutations of â¼7.8 per 100 000 individuals. Structural modelling of the novel eight AP2σ variants (Arg3His, Ala44Thr, Phe52Tyr, Arg61His, Thr112Met, Met117Ile, Glu122Gly and Glu142Lys) predicted that the Arg3His, Thr112Met, Glu122Gly and Glu142Lys AP2σ variants would disrupt polar contacts within the AP2σ subunit or affect the interface between the AP2σ and AP2α subunits. Functional analyses of all eight AP2σ variants in CaSR-expressing cells demonstrated that the Thr112Met, Met117Ile and Glu142Lys variants, located in the AP2σ α4-α5 helical region that forms an interface with AP2α, impaired CaSR-mediated intracellular calcium (Cai2+) signalling, consistent with a loss of function, and this was rectified by treatment with the CaSR positive allosteric modulator cinacalcet. Thus, our studies demonstrate another potential class of FHH3-causing AP2σ mutations located at the AP2σ-AP2α interface.
Asunto(s)
Subunidades alfa de Complejo de Proteína Adaptadora/metabolismo , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Mutación , Receptores Sensibles al Calcio/metabolismo , Complejo 2 de Proteína Adaptadora/genética , Complejo 2 de Proteína Adaptadora/metabolismo , Subunidades sigma de Complejo de Proteína Adaptadora/metabolismo , Cinacalcet/farmacología , Bases de Datos Genéticas , Exoma , Femenino , Humanos , Hipercalcemia/tratamiento farmacológico , Hipercalcemia/genética , Masculino , Persona de Mediana Edad , Modelos Moleculares , Conformación Proteica , Transducción de Señal , Secuenciación del ExomaRESUMEN
Copper has previously been implicated in the regulation of immune responses, but the impact of this metal on mast cells is poorly understood. In this article, we address this issue and show that copper starvation of mast cells causes increased granule maturation, as indicated by higher proteoglycan content, stronger metachromatic staining, and altered ultrastructure in comparison with nontreated cells, whereas copper overload has the opposite effects. In contrast, copper status did not impact storage of histamine in mast cells, nor did alterations in copper levels affect the ability of mast cells to degranulate in response to IgER cross-linking. A striking finding was decreased tryptase content in mast cells with copper overload, whereas copper starvation increased tryptase content. These effects were associated with corresponding shifts in tryptase mRNA levels, suggesting that copper affects tryptase gene regulation. Mechanistically, we found that alterations in copper status affected the expression of microphthalmia-associated transcription factor, a transcription factor critical for driving tryptase expression. We also found evidence supporting the concept that the effects on microphthalmia-associated transcription factor are dependent on copper-mediated modulation of MAPK signaling. Finally, we show that, in MEDNIK syndrome, a condition associated with low copper levels and a hyperallergenic skin phenotype, including pruritis and dermatitis, the number of tryptase-positive mast cells is increased. Taken together, our findings reveal a hitherto unrecognized role for copper in the regulation of mast cell gene expression and maturation.
Asunto(s)
Cobre/farmacología , Mastocitos/efectos de los fármacos , Factor de Transcripción Asociado a Microftalmía/fisiología , Triptasas/fisiología , Complejo 1 de Proteína Adaptadora/deficiencia , Complejo 1 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/deficiencia , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Adulto , Animales , Proteínas de Transporte de Catión/metabolismo , Degranulación de la Célula/efectos de los fármacos , Forma de la Célula/efectos de los fármacos , Células Cultivadas , Preescolar , Cobre/deficiencia , Cobre/fisiología , Transportador de Cobre 1 , Inducción Enzimática/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Liberación de Histamina/efectos de los fármacos , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Mastocitos/citología , Mastocitos/metabolismo , Mastocitosis Cutánea/inmunología , Mastocitosis Cutánea/patología , Ratones , Ratones Endogámicos C57BL , Proteoglicanos/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de IgE/inmunología , Piel/patología , Síndrome , Triptasas/biosíntesis , Triptasas/genéticaRESUMEN
Context: Familial hypocalciuric hypercalcemia (FHH) causes lifelong hypercalcemia that even persists after subtotal parathyroidectomy. Symptoms are usually mild. Past recommendations have often been for monitoring and against surgical or pharmacologic treatments. Methods: Review of publications about FHH, calcium-sensing receptors (CaSRs), and calcimimetics. Results: FHH reflects heterozygous germline mutation of CASR, GNA11, or AP2S1. These mutations inactivate the CaSRs in the parathyroid cell. Thereby, they shift the serum calcium set point to higher values and cause hypercalcemia. Calcimimetic drugs enhance the effects of calcium on the CaSRs and thereby inhibit the parathyroid cell. Calcimimetic drugs are indicated in adults with primary hyperparathyroidism without a good surgical option. Calcimimetic safety and efficacy are not established in children younger than age 18 years. Recent case reports have described treatment of FHH with calcimimetics. Success was classified as combinations of subjective improvements and decreases of serum calcium levels, but not necessarily into the normal range. Treatment was successful in 14 of 16 cases (88%). Conclusion: Deductions based on these case reports have limitations. For example, failures of therapy may not have been reported. Cost of the drug might be rate limiting. Calcimimetics can be offered to adults with FHH and those in whom the serum calcium level is >0.25 mM (1 mg/dL) beyond the upper limit of normal or with possible symptoms of hypercalcemia. Calcimimetics can now be offered to more adults with FHH.
Asunto(s)
Calcimiméticos/uso terapéutico , Hipercalcemia/congénito , Complejo 2 de Proteína Adaptadora/genética , Subunidades sigma de Complejo de Proteína Adaptadora/genética , Adolescente , Adulto , Niño , Preescolar , Endocrinología/tendencias , Subunidades alfa de la Proteína de Unión al GTP/genética , Humanos , Hipercalcemia/tratamiento farmacológico , Hipercalcemia/genética , Hiperparatiroidismo Primario/diagnóstico , Hiperparatiroidismo Primario/genética , Lactante , Recién Nacido , Receptores Sensibles al Calcio/genéticaRESUMEN
γ2 adaptin is homologous to γ1, but is only expressed in vertebrates while γ1 is found in all eukaryotes. We know little about γ2 functions and their relation to γ1. γ1 is an adaptin of the heterotetrameric AP-1 complexes, which sort proteins in and do form clathrin-coated transport vesicles and they also regulate maturation of early endosomes. γ1 knockout mice develop only to blastocysts and thus γ2 does not compensate γ1-deficiency in development. γ2 has not been classified as a clathrin-coated vesicle adaptor protein in proteome analyses and functions for monomeric γ2 in endosomal protein sorting have been proposed, but adaptin interaction studies suggested formation of heterotetrameric AP-1/γ2 complexes. We detected γ2 at the trans-Golgi network, on peripheral vesicles and identified γ2 clathrin-coated vesicles in mice. Ubiquitous σ1A and tissue-specific σ1B adaptins bind γ2 and γ1. σ1B knockout in mice does not effect γ1/σ1A AP-1 levels, but γ2/σ1A AP-1 levels are increased in brain and adipocytes. Also γ2 is essential in development. In zebrafish AP-1/γ2 and AP-1/γ1 fulfill different, essential functions in brain and the vascular system.