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1.
JCI Insight ; 2024 Sep 12.
Article in English | MEDLINE | ID: mdl-39264853

ABSTRACT

Despite advances in sequencing technologies, a molecular diagnosis remains elusive in many Mendelian disease patients. Current short-read clinical sequencing approaches cannot provide chromosomal phase information or epigenetic information without further sample processing, which is not routinely done and can result in an incomplete molecular diagnosis in patients. The ability to provide phased genetic and epigenetic information from a single sequencing run would improve the diagnostic rate of Mendelian conditions. Here we describe Targeted Long-read Sequencing of Mendelian Disease genes (TaLon-SeqMD) using a real-time adaptive sequencing approach. Optimization of bioinformatic targeting enabled selective enrichment of multiple disease-causing regions of the human genome. Haplotype-resolved variant calling and simultaneous resolution of epigenetic base modification could be achieved in a single sequencing run. The TaLon-SeqMD approach was validated in a cohort of 18 subjects with previous genetic testing targeting 373 inherited retinal disease (IRD) genes, yielding the complete molecular diagnosis in each case. This approach was then applied in two IRD cases with inconclusive testing, which uncovered non-coding and structural variants that were difficult to characterize by standard short-read sequencing. Overall, these results demonstrate TaLon-SeqMD as an approach to provide rapid phased-variant calling to provide the molecular basis of Mendelian diseases.

2.
J Biol Chem ; : 107772, 2024 Sep 12.
Article in English | MEDLINE | ID: mdl-39276938

ABSTRACT

Lipid-rich deposits called drusen accumulate under the retinal pigment epithelium (RPE) in the eyes of patients with age-related macular degeneration (AMD) and Sorsby's fundus dystrophy (SFD). Drusen may contribute to photoreceptor and RPE degeneration in these blinding diseases. We hypothesize that stimulating ß-oxidation of fatty acids could decrease the availability of lipid with which RPE cells can generate drusen. Inhibitors of acetyl-CoA carboxylase (ACC) stimulate ß-oxidation and diminish lipid accumulation in fatty liver disease. In this report we test the hypothesis that an ACC inhibitor, Firsocostat, can diminish lipid deposition by RPE cells. We probed metabolism and cellular function in mouse RPE-choroid tissue and in cultured human RPE cells. We used 13C6-glucose, 13C16-palmitate, and gas chromatography-linked mass spectrometry to monitor effects of Firsocostat on glycolytic, Krebs cycle, and fatty acid metabolism. We quantified lipid abundance, apolipoprotein E (ApoE) and vascular endothelial growth factor (VEGF) release using liquid chromatography-mass spectrometry, enzyme-linked immunosorbent assays and localized ApoE deposits by immunostaining. RPE barrier function was assessed by trans-epithelial electrical resistance (TEER). Firsocostat-mediated ACC inhibition increases ß-oxidation, decreases intracellular lipid levels, diminishes lipoprotein release, and increases TEER. When human serum or outer segments are used to stimulate lipoprotein release, fewer lipoproteins are released in the presence of either lipid source and Firsocostat. In a culture model of SFD, Firsocostat stimulates fatty acid oxidation, increases TEER, and decreases ApoE release. We conclude that Firsocostat remodels RPE metabolism and can limit lipid deposition. This suggests that ACC inhibition could be an effective strategy for diminishing pathologic drusen in the eyes of patients with AMD or SFD.

3.
Invest Ophthalmol Vis Sci ; 65(11): 5, 2024 09 03.
Article in English | MEDLINE | ID: mdl-39230994

ABSTRACT

Purpose: Metabolic defects in the retinal pigment epithelium (RPE) underlie many retinal degenerative diseases. This study aims to identify the nutrient requirements of healthy and diseased human RPE cells. Methods: We profiled nutrient use of various human RPE cells, including differentiated and dedifferentiated fetal RPE (fRPE), induced pluripotent stem cell-derived RPE (iPSC RPE), Sorsby fundus dystrophy (SFD) patient-derived iPSC RPE, CRISPR-corrected isogenic SFD (cSFD) iPSC RPE, and ARPE-19 cell lines using Biolog Phenotype MicroArray Assays. Results: Differentiated fRPE cells and healthy iPSC RPE cells can use 51 and 48 nutrients respectively, including sugars, intermediates from glycolysis and tricarboxylic acid (TCA) cycle, fatty acids, ketone bodies, amino acids, and dipeptides. However, when fRPE cells lose their epithelial phenotype through dedifferentiation, nutrient use becomes restricted to 17 nutrients, primarily sugar and glutamine-related amino acids. SFD RPE cells can use 37 nutrients; however, compared to cSFD RPE and healthy iPSC RPE, they are unable to use lactate, some TCA cycle intermediates, and short-chain fatty acids. Nonetheless, they show increased use of branch-chain amino acids (BCAAs) and BCAA-containing dipeptides. Dedifferentiated ARPE-19 cells grown in traditional culture media cannot use lactate and ketone bodies. In contrast, nicotinamide supplementation promotes differentiation toward an epithelial phenotype, restoring the ability to use these nutrients. Conclusions: Epithelial phenotype confers metabolic flexibility to healthy RPE for using various nutrients. SFD RPE cells have reduced metabolic flexibility, relying on the oxidation of BCAAs. Our findings highlight the potentially important roles of nutrient availability and use in RPE differentiation and diseases.


Subject(s)
Cell Differentiation , Induced Pluripotent Stem Cells , Phenotype , Retinal Pigment Epithelium , Humans , Retinal Pigment Epithelium/metabolism , Retinal Pigment Epithelium/cytology , Cell Differentiation/physiology , Induced Pluripotent Stem Cells/metabolism , Induced Pluripotent Stem Cells/cytology , Cells, Cultured , Cell Line
4.
Invest Ophthalmol Vis Sci ; 65(10): 45, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39207297

ABSTRACT

Purpose: Retinitis pigmentosa (RP), the most common inherited retinal disease, is characterized by progressive photoreceptor degeneration. It remains unknown to what extent surviving photoreceptors transduce light and support vision in RP. To address this, we correlated structure and functional measures using adaptive optics scanning laser ophthalmoscopy (AOSLO), adaptive optics microperimetry, and adaptive optics optical coherence tomography (AO-OCT)-based optoretinograms (ORGs). Methods: Four patients with RP were imaged with AOSLO across the visual field covering the transition zone (TZ) of normal to diseased retina. Cone density was estimated in discrete regions spanning the TZ. Visual sensitivity was assessed by measuring increment thresholds for a 3-arcmin stimulus targeted via active eye tracking in AOSLO. ORGs were measured at the same locations using AO-OCT to assess the cones' functional response to a 528 ± 20-nm stimulus. Individual cone outer segment (COS) lengths were measured from AO-OCT in each subject. Results: Cone density was significantly reduced in patients with RP. Density reduction correlated with TZ location in 3 patients with RP, while a fourth had patches of reduced density throughout the retina. ORG amplitude was reduced in regions of normal and reduced cone density in all patients with RP. ORG response and COS length were positively correlated in controls but not in patients with RP. Despite deficits in cone density and ORG, visual sensitivity remained comparable to controls in three of four patients with RP. Conclusions: ORG-based measures of retinal dysfunction may precede deficits in cone structure and visual sensitivity. ORG is a sensitive measure of RP disease status and has significant potential to provide insight into disease progression and treatment efficacy.


Subject(s)
Ophthalmoscopy , Retinal Cone Photoreceptor Cells , Retinitis Pigmentosa , Tomography, Optical Coherence , Visual Acuity , Visual Field Tests , Visual Fields , Humans , Retinitis Pigmentosa/physiopathology , Retinitis Pigmentosa/diagnosis , Tomography, Optical Coherence/methods , Retinal Cone Photoreceptor Cells/pathology , Retinal Cone Photoreceptor Cells/physiology , Ophthalmoscopy/methods , Male , Female , Visual Field Tests/methods , Adult , Visual Acuity/physiology , Visual Fields/physiology , Middle Aged , Multimodal Imaging , Cell Count
5.
Exp Eye Res ; 245: 109966, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38857822

ABSTRACT

The retinal pigment epithelium (RPE) is omnivorous and can utilize a wide range of substrates for oxidative phosphorylation. Certain tissues with high mitochondrial metabolic load are capable of ketogenesis, a biochemical pathway that consolidates acetyl-CoA into ketone bodies. Earlier work demonstrated that the RPE expresses the rate-limiting enzyme for ketogenesis, 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), and that the RPE indeed produces ketone bodies, including beta-hydroxybutyrate (ß-HB). Prior work, based on detecting ß-HB via enzymatic assays, suggested that differentiated cultures of primary RPE preferentially export ß-HB across the apical membrane. Here, we compare the accuracy of measuring ß-HB by enzymatic assay kits to mass spectrometry analysis. We found that commercial kits lack the sensitivity to accurately measure the levels of ß-HB in RPE cultures and are prone to artifact. Using mass spectrometry, we found that while RPE cultures secrete ß-HB, they do so equally to both apical and basal sides. We also find RPE is capable of consuming ß-HB as levels rise. Using isotopically labeled glucose, amino acid, and fatty acid tracers, we found that carbons from both fatty acids and ketogenic amino acids, but not from glucose, produce ß-HB. Altogether, we substantiate ß-HB secretion in RPE but find that the secretion is equal apically and basally, RPE ß-HB can derive from ketogenic amino acids or fatty acids, and accurate ß-HB assessment requires mass spectrometric analysis.


Subject(s)
3-Hydroxybutyric Acid , Ketone Bodies , Retinal Pigment Epithelium , Retinal Pigment Epithelium/metabolism , Ketone Bodies/metabolism , Cells, Cultured , 3-Hydroxybutyric Acid/metabolism , Humans , Enzyme Assays/methods , Hydroxymethylglutaryl-CoA Synthase/metabolism , Mass Spectrometry , Animals
6.
Invest Ophthalmol Vis Sci ; 65(4): 43, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38683564

ABSTRACT

Purpose: Complement dysregulation is a key component in the pathogenesis of age-related macular degeneration (AMD) and related diseases such as early-onset macular drusen (EOMD). Although genetic variants of complement factor H (CFH) are associated with AMD risk, the impact of CFH and factor H-like protein 1 (FHL-1) expression on local complement activity in human retinal pigment epithelium (RPE) remains unclear. Methods: We identified a novel CFH variant in a family with EOMD and generated patient induced pluripotent stem cell (iPSC)-derived RPE cells. We assessed CFH and FHL-1 co-factor activity through C3b breakdown assays and measured complement activation by immunostaining for membrane attack complex (MAC) formation. Expression of CFH, FHL-1, local alternative pathway (AP) components, and regulators of complement activation (RCA) in EOMD RPE cells was determined by quantitative PCR, western blot, and immunostaining. Isogenic EOMD (cEOMD) RPE was generated using CRISPR/Cas9 gene editing. Results: The CFH variant (c.351-2A>G) resulted in loss of CFH and FHL-1 expression and significantly reduced CFH and FHL-1 protein expression (∼50%) in EOMD iPSC RPE cells. These cells exhibited increased MAC deposition upon exposure to normal human serum. Under inflammatory or oxidative stress conditions, CFH and FHL-1 expression in EOMD RPE cells paralleled that of controls, whereas RCA expression, including MAC formation inhibitors, was elevated. CRISPR/Cas9 correction restored CFH/FHL-1 expression and mitigated alternative pathway complement activity in cEOMD RPE cells. Conclusions: Identification of a novel CFH variant in patients with EOMD resulting in reduced CFH and FHL-1 and increased local complement activity in EOMD iPSC RPE supports the involvement of CFH haploinsufficiency in EOMD pathogenesis.


Subject(s)
Complement Factor H , Haploinsufficiency , Intracellular Signaling Peptides and Proteins , LIM Domain Proteins , Macular Degeneration , Muscle Proteins , Retinal Pigment Epithelium , Humans , Complement Factor H/genetics , Complement Factor H/metabolism , Retinal Pigment Epithelium/metabolism , Retinal Pigment Epithelium/pathology , Macular Degeneration/genetics , Macular Degeneration/metabolism , Male , Female , Induced Pluripotent Stem Cells/metabolism , Complement C3b Inactivator Proteins/genetics , Complement C3b Inactivator Proteins/metabolism , Complement Activation/genetics , Pedigree , Blotting, Western , Complement System Proteins/metabolism , Complement System Proteins/genetics , Retinal Drusen/genetics , Retinal Drusen/metabolism , Middle Aged
7.
bioRxiv ; 2024 Jul 18.
Article in English | MEDLINE | ID: mdl-38464098

ABSTRACT

Purpose: Metabolic defects in the retinal pigment epithelium (RPE) underlie many retinal degenerative diseases. This study aims to identify the nutrient requirements of healthy and diseased human RPE cells. Methods: We profiled nutrient utilization of various human RPE cells, including differentiated and dedifferentiated fetal RPE (fRPE), induced pluripotent stem cell derived-RPE (iPSC RPE), Sorsby fundus dystrophy (SFD) patient-derived iPSC RPE, CRISPR-corrected isogenic SFD (cSFD) iPSC RPE, and ARPE-19 cell lines using Biolog Phenotype MicroArray Assays. Results: Differentiated fRPE cells and healthy iPSC RPE cells can utilize 51 and 48 nutrients respectively, including sugars, intermediates from glycolysis and tricarboxylic acid (TCA) cycle, fatty acids, ketone bodies, amino acids, and dipeptides. However, when fRPE cells lose their epithelial phenotype through dedifferentiation, nutrient utilization becomes restricted to 17 nutrients, primarily sugar and glutamine-related amino acids. SFD RPE cells can utilize 37 nutrients; however, compared to cSFD RPE and healthy iPSC RPE, they are unable to utilize lactate, some TCA cycle intermediates, and short-chain fatty acids. Nonetheless, they show increased utilization of branch-chain amino acids (BCAAs) and BCAA-containing dipeptides. Dedifferentiated ARPE-19 cells grown in traditional culture media cannot utilize lactate and ketone bodies. In contrast, nicotinamide supplementation promotes differentiation towards an epithelial phenotype, restoring the ability to use these nutrients. Conclusions: Epithelial phenotype confers metabolic flexibility to healthy RPE for utilizing various nutrients. SFD RPE cells have reduced metabolic flexibility, relying on the oxidation of BCAAs. Our findings highlight the potentially important roles of nutrient availability and utilization in RPE differentiation and diseases.

8.
bioRxiv ; 2023 Nov 08.
Article in English | MEDLINE | ID: mdl-37986876

ABSTRACT

Purpose: In age-related macular degeneration (AMD) and Sorsby's fundus dystrophy (SFD), lipid-rich deposits known as drusen accumulate under the retinal pigment epithelium (RPE). Drusen may contribute to photoreceptor and RPE degeneration in AMD and SFD. We hypothesize that stimulating ß-oxidation in RPE will reduce drusen accumulation. Inhibitors of acetyl-CoA carboxylase (ACC) stimulate ß-oxidation and diminish lipid accumulation in fatty liver disease. In this report we test the hypothesis that an ACC inhibitor, Firsocostat, limits the accumulation of lipid deposits in cultured RPE cells. Methods: We probed metabolism and cellular function in mouse RPE-choroid, human fetal- derived RPE cells, and induced pluripotent stem cell-derived RPE cells. We used 13 C6-glucose and 13 C16-palmitate to determine the effects of Firsocostat on glycolytic, Krebs cycle, and fatty acid metabolism. 13 C labeling of metabolites in these pathways were analyzed using gas chromatography-linked mass spectrometry. We quantified ApoE and VEGF release using enzyme-linked immunosorbent assays. Immunostaining of sectioned RPE was used to visualize ApoE deposits. RPE function was assessed by measuring the trans-epithelial electrical resistance (TEER). Results: ACC inhibition with Firsocostat increases fatty acid oxidation and remodels lipid composition, glycolytic metabolism, lipoprotein release, and enhances TEER. When human serum is used to induce sub-RPE lipoprotein accumulation, fewer lipoproteins accumulate with Firsocostat. In a culture model of Sorsby's fundus dystrophy, Firsocostat also stimulates fatty acid oxidation, improves morphology, and increases TEER. Conclusions: Firsocostat remodels intracellular metabolism and improves RPE resilience to serum-induced lipid deposition. This effect of ACC inhibition suggests that it could be an effective strategy for diminishing drusen accumulation in the eyes of patients with AMD.

9.
J Biol Chem ; 299(11): 105275, 2023 11.
Article in English | MEDLINE | ID: mdl-37741457

ABSTRACT

It is known that metabolic defects in the retinal pigment epithelium (RPE) can cause degeneration of its neighboring photoreceptors in the retina, leading to retinal degenerative diseases such as age-related macular degeneration. However, how RPE metabolism supports the health of the neural retina remains unclear. The retina requires exogenous nitrogen sources for protein synthesis, neurotransmission, and energy metabolism. Using 15N tracing coupled with mass spectrometry, we found human RPE can utilize the nitrogen in proline to produce and export 13 amino acids, including glutamate, aspartate, glutamine, alanine, and serine. Similarly, we found this proline nitrogen utilization in the mouse RPE/choroid but not in the neural retina of explant cultures. Coculture of human RPE with the retina showed that the retina can take up the amino acids, especially glutamate, aspartate, and glutamine, generated from proline nitrogen in the RPE. Intravenous delivery of 15N proline in vivo demonstrated 15N-derived amino acids appear earlier in the RPE before the retina. We also found proline dehydrogenase, the key enzyme in proline catabolism is highly enriched in the RPE but not the retina. The deletion of proline dehydrogenase blocks proline nitrogen utilization in RPE and the import of proline nitrogen-derived amino acids in the retina. Our findings highlight the importance of RPE metabolism in supporting nitrogen sources for the retina, providing insight into understanding the mechanisms of the retinal metabolic ecosystem and RPE-initiated retinal degenerative diseases.


Subject(s)
Amino Acids , Retinal Pigment Epithelium , Animals , Humans , Mice , Amino Acids/metabolism , Aspartic Acid/metabolism , Glutamates/metabolism , Glutamine/metabolism , Nitrogen/metabolism , Proline/metabolism , Proline Oxidase/metabolism , Retina/metabolism , Retinal Pigment Epithelium/metabolism
10.
NPJ Genom Med ; 8(1): 20, 2023 Aug 10.
Article in English | MEDLINE | ID: mdl-37558662

ABSTRACT

Phasing genetic variants is essential in determining those that are potentially disease-causing. In autosomal recessive inherited retinal diseases (IRDs), reclassification of variants of uncertain significance (VUS) can provide a genetic diagnosis in indeterminate compound heterozygote cases. We report four cases in which familial co-segregation demonstrated a VUS resided in trans to a known pathogenic variant, which in concert with other supporting criteria, led to the reclassification of the VUS to likely pathogenic, thereby providing a genetic diagnosis in each case. We also demonstrate in a simplex patient without access to family members for co-segregation analysis that targeted long-read sequencing can provide haplotagged variant calling. This can elucidate if variants reside in trans and provide phase of genetic variants from the proband alone without parental testing. This emerging method can alleviate the bottleneck of haplotype analysis in cases where genetic testing of family members is unfeasible to provide a complete genetic diagnosis.

11.
J Vis Exp ; (197)2023 07 14.
Article in English | MEDLINE | ID: mdl-37522735

ABSTRACT

Many in vitro models used to investigate tissue function and cell biology require a flow of media to provide adequate oxygenation and optimal cell conditions required for the maintenance of function and viability. Toward this end, we have developed a multi-channel flow culture system to maintain tissue and cells in culture and continuously assess function and viability by either in-line sensors and/or collection of outflow fractions. The system combines 8-channel, continuous optical sensing of oxygen consumption rate with a built-in fraction collector to simultaneously measure production rates of metabolites and hormone secretion. Although it is able to maintain and assess a wide range of tissue and cell models, including islets, muscle, and hypothalamus, here we describe its operating principles and the experimental preparations/protocols that we have used to investigate bioenergetic regulation of isolated mouse retina, mouse retinal pigment epithelium (RPE)-choroid-sclera, and cultured human RPE cells. Innovations in the design of the system, such as pumpless fluid flow, have produced a greatly simplified operation of a multi-channel flow system. Videos and images are shown that illustrate how to assemble, prepare the instrument for an experiment, and load the different tissue/cell models into the perifusion chambers. In addition, guidelines for selecting conditions for protocol- and tissue-specific experiments are delineated and discussed, including setting the correct flow rate to tissue ratio to obtain consistent and stable culture conditions and accurate determinations of consumption and production rates. The combination of optimal tissue maintenance and real-time assessment of multiple parameters yields highly informative data sets that will have great utility for research in the physiology of the eye and drug discovery for the treatment of impaired vision.


Subject(s)
Choroid , Retinal Pigment Epithelium , Mice , Humans , Animals , Cells, Cultured , Choroid/metabolism , Sclera/metabolism , Biological Transport/physiology
12.
Ann Emerg Med ; 82(5): 615-623, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37178102

ABSTRACT

STUDY OBJECTIVES: Ketorolac is a commonly used nonopioid parenteral analgesic for treating emergency department (ED) patients with acute pain. Our systematic review aims to summarize the available evidence by comparing the efficacy and safety of differing ketorolac dosing strategies for acute pain relief in the ED. METHODS: The review was registered on PROSPERO (CRD42022310062). We searched MEDLINE, PubMed, EMBASE, and unpublished sources from inception through December 9, 2022. We included randomized control trials of patients presenting with acute pain to the ED, comparing ketorolac doses less than 30 mg (low dose) to ketorolac doses more than or equal to 30 mg (high dose) for the outcomes of pain scores after treatment need for rescue analgesia, and incidence of adverse events. We excluded patients in non-ED settings, including postoperative settings. We extracted data independently and in duplicate and pooled them using a random-effects model. We assessed the risk of bias using the Cochrane Risk of Bias 2 tool and the overall certainty of the evidence for each outcome using the Grading Recommendations Assessment, Development, and Evaluation approach. RESULTS: This review included 5 randomized controlled trials (n=627 patients). Low-dose parenteral ketorolac (15 to 20 mg), as compared to high-dose ketorolac (≥30 mg), probably has no effect on pain scores (mean difference 0.05 mm lower on 100 mm visual analog scale, 95% confidence interval [CI] -4.91 mm to +5.01 mm; moderate certainty). Further, low-dose ketorolac at 10 mg may have no effect on pain scores compared to high-dose ketorolac (mean difference 1.58 mm lower on 100 mm visual analog scale, 95% CI -8.86 mm to +5.71 mm; low certainty). Low-dose ketorolac may increase the need for rescue analgesia (risk ratio 1.27, 95% CI 0.86 to 1.87; low certainty) and may have no difference on rates of adverse events (risk ratio 0.84, 95% CI 0.54 to 1.33; low certainty). CONCLUSION: In adult ED patients with acute pain, parenteral ketorolac given at doses of 10 mg to 20 mg is probably as effective in relieving pain as doses of 30 mg or higher. Low-dose ketorolac may have no effect on adverse events, but these patients may require more rescue analgesia. This evidence is limited by imprecision and is not generalizable to children or those at higher risk of adverse events.

13.
Sci Rep ; 13(1): 8535, 2023 05 26.
Article in English | MEDLINE | ID: mdl-37237007

ABSTRACT

Inherited retinal degenerations (IRDs) are a heterogeneous group of predominantly monogenic disorders with over 300 causative genes identified. Short-read exome sequencing is commonly used to genotypically diagnose patients with clinical features of IRDs, however, in up to 30% of patients with autosomal recessive IRDs, one or no disease-causing variants are identified. Furthermore, chromosomal maps cannot be reconstructed for allelic variant discovery with short-reads. Long-read genome sequencing can provide complete coverage of disease loci and a targeted approach can focus sequencing bandwidth to a genomic region of interest to provide increased depth and haplotype reconstruction to uncover cases of missing heritability. We demonstrate that targeted adaptive long-read sequencing on the Oxford Nanopore Technologies (ONT) platform of the USH2A gene from three probands in a family with the most common cause of the syndromic IRD, Usher Syndrome, resulted in greater than 12-fold target gene sequencing enrichment on average. This focused depth of sequencing allowed for haplotype reconstruction and phased variant identification. We further show that variants obtained from the haplotype-aware genotyping pipeline can be heuristically ranked to focus on potential pathogenic candidates without a priori knowledge of the disease-causing variants. Moreover, consideration of the variants unique to targeted long-read sequencing that are not covered by short-read technology demonstrated higher precision and F1 scores for variant discovery by long-read sequencing. This work establishes that targeted adaptive long-read sequencing can generate targeted, chromosome-phased data sets for identification of coding and non-coding disease-causing alleles in IRDs and can be applicable to other Mendelian diseases.


Subject(s)
Retinal Degeneration , Usher Syndromes , Humans , Pedigree , Retinal Degeneration/genetics , Usher Syndromes/genetics , Sequence Analysis, DNA/methods , Alleles , High-Throughput Nucleotide Sequencing
14.
bioRxiv ; 2023 Apr 28.
Article in English | MEDLINE | ID: mdl-37131780

ABSTRACT

It is known that metabolic defects in the retinal pigment epithelium (RPE) can cause degeneration of its neighboring photoreceptors in the retina, leading to retinal degenerative diseases such as age-related macular degeneration. However, how RPE metabolism supports the health of the neural retina remains unclear. The retina requires exogenous nitrogen sources for protein synthesis, neurotransmission, and energy metabolism. Using 15N tracing coupled with mass spectrometry, we found human RPE can utilize the nitrogen in proline to produce and export 13 amino acids, including glutamate, aspartate, glutamine, alanine and serine. Similarly, we found this proline nitrogen utilization in the mouse RPE/choroid but not in the neural retina of explant cultures. Co-culture of human RPE with the retina showed that the retina can take up the amino acids, especially glutamate, aspartate and glutamine, generated from proline nitrogen in the RPE. Intravenous delivery of 15N proline in vivo demonstrated 15N-derived amino acids appear earlier in the RPE before the retina. We also found proline dehydrogenase (PRODH), the key enzyme in proline catabolism is highly enriched in the RPE but not the retina. The deletion of PRODH blocks proline nitrogen utilization in RPE and the import of proline nitrogen-derived amino acids in the retina. Our findings highlight the importance of RPE metabolism in supporting nitrogen sources for the retina, providing insight into understanding the mechanisms of the retinal metabolic ecosystem and RPE-initiated retinal degenerative diseases.

15.
Bioinformatics ; 39(1)2023 01 01.
Article in English | MEDLINE | ID: mdl-36648314

ABSTRACT

MOTIVATION: Timetrees depict evolutionary relationships between species and the geological times of their divergence. Hundreds of research articles containing timetrees are published in scientific journals every year. The TimeTree (TT) project has been manually locating, curating and synthesizing timetrees from these articles for almost two decades into a TimeTree of Life, delivered through a unique, user-friendly web interface (timetree.org). The manual process of finding articles containing timetrees is becoming increasingly expensive and time-consuming. So, we have explored the effectiveness of text-mining approaches and developed optimizations to find research articles containing timetrees automatically. RESULTS: We have developed an optimized machine learning system to determine if a research article contains an evolutionary timetree appropriate for inclusion in the TT resource. We found that BERT classification fine-tuned on whole-text articles achieved an F1 score of 0.67, which we increased to 0.88 by text-mining article excerpts surrounding the mentioning of figures. The new method is implemented in the TimeTreeFinder (TTF) tool, which automatically processes millions of articles to discover timetree-containing articles. We estimate that the TTF tool would produce twice as many timetree-containing articles as those discovered manually, whose inclusion in the TT database would potentially double the knowledge accessible to a wider community. Manual inspection showed that the precision on out-of-distribution recently published articles is 87%. This automation will speed up the collection and curation of timetrees with much lower human and time costs. AVAILABILITY AND IMPLEMENTATION: https://github.com/marija-stanojevic/time-tree-classification. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Subject(s)
Biological Evolution , Data Mining , Humans , Phylogeny , Databases, Factual , Machine Learning
17.
J Emerg Med ; 63(2): 159-168, 2022 08.
Article in English | MEDLINE | ID: mdl-35691767

ABSTRACT

BACKGROUND: Febrile neonates undergo lumbar puncture (LP), empiric antibiotic administration, and admission for increased risk of invasive bacterial infection (IBI), defined as bacteremia and meningitis. OBJECTIVE: Measure IBI prevalence in febrile neonates, and operating characteristics of Rochester Criteria (RC), Yale Observation Scale (YOS) score, and demographics as a low-risk screening tool. METHODS: Secondary analysis of healthy febrile infants < 60 days old presenting to any of 26 emergency departments in the Pediatric Emergency Care Applied Research Network between December 2008 and May 2013. Of 7334 infants, 1524 met our inclusion criteria of age ≤ 28 days. All had fevers and underwent evaluation for IBI. Receiver operator characteristic (ROC) curve and transparent decision tree analysis were used to determine the applicability of reassuring RC, YOS, and age parameters as an IBI low-risk screening tool. RESULTS: Of 1524 neonates, 2.9% had bacteremia and 1.5% had meningitis. After applying RC and YOS, 15 neonates were incorrectly identified as low risk for IBI (10 bacteremia, 4 meningitis, 1 bacteremia, and meningitis). Age ≤ 18 days was a statistically significant variable ROC (area under curve 0.63, p < 0.05). Incorporating age > 18 days as low-risk criteria with reassuring RC and YOS misclassified 7 IBI patients (6 bacteremia, 1 meningitis). CONCLUSION: Thirty percent of febrile neonates met low-risk criteria, age > 18 days, reassuring RC and YOS, and could avoid LP and empiric antibiotics. Our low-risk guidelines may improve patient safety and reduce health care costs by decreasing lab testing for cerebrospinal fluid, empiric antibiotic administration, and prolonged hospitalization. These results are hypothesis-generating and should be verified with a randomized prospective study.


Subject(s)
Bacteremia , Bacterial Infections , Meningitis, Bacterial , Adult , Anti-Bacterial Agents/therapeutic use , Bacteremia/complications , Bacterial Infections/complications , Child , Fever/diagnosis , Humans , Infant , Infant, Newborn , Meningitis, Bacterial/complications , Meningitis, Bacterial/diagnosis , Middle Aged , Prospective Studies , Retrospective Studies
18.
Am J Emerg Med ; 56: 137-144, 2022 06.
Article in English | MEDLINE | ID: mdl-35397354

ABSTRACT

OBJECTIVE: New York City (NYC) is home to the largest public healthcare system in the United States and was an early epicenter of coronavirus disease 2019 (COVID-19) infections. This system serves as the safety net for underserved and marginalized communities disproportionately affected by the pandemic. Prior studies reported substantial declines in pediatric emergency department (ED) volume during the initial pandemic surge, but few describe the ongoing impact of COVID-19 throughout the year. We evaluated the characteristics of pediatric ED visits to NYC public hospitals during the pandemic lockdown and reopening periods of 2020 compared to the prior year. METHODS: Retrospective cross-sectional analysis of pediatric ED visits from 11 NYC public hospitals from January 2019-December 2020. Visit demographics, throughput times, and diagnosis information during the early (3/7/20-6/7/20) and late (6/8/20-12/31/20) pandemic periods coinciding with the New York State of emergency declaration (3/7/20) and the first reopening date (6/7/20) were compared to similar time periods in 2019. Findings were correlated with key pandemic shutdown and reopening events. RESULTS: There was a 47% decrease in ED volume in 2020 compared to 2019 (125,649 versus 238,024 visits). After reopening orders began in June 2020, volumes increased but peaked at <60% of 2019 volumes. Admission rates, triage acuity, and risk of presenting with a serious medical illness were significantly higher in 2020 versus 2019 (P < 0.001). Time-to-provider times decreased however provider-to-disposition times increased during the pandemic (P < 0.001). Infectious and asthma diagnoses declined >70% during the pandemic in contrast to the year prior. After reopening periods began, penetrating traumatic injuries significantly increased compared to 2019 [+34%, Relative Risk: 3.2 (2.6, 3.8)]. CONCLUSIONS: NYC public hospitals experienced a sharp decrease in pediatric volume but an increase in patient acuity during both the initial pandemic surge and through the reopening periods. As COVID-19 variants emerge, the threat of the current pandemic expanding remains. Understanding its influence on pediatric ED utilization can optimize resource allocation and ensure equitable care for future surge events.


Subject(s)
COVID-19 , Pandemics , COVID-19/epidemiology , Child , Communicable Disease Control , Cross-Sectional Studies , Emergency Service, Hospital , Humans , New York City/epidemiology , Retrospective Studies , SARS-CoV-2 , United States
19.
Ophthalmol Retina ; 6(8): 702-710, 2022 08.
Article in English | MEDLINE | ID: mdl-35307606

ABSTRACT

PURPOSE: To evaluate genetic testing platforms used to aid in the diagnosis of inherited retinal degenerations (IRDs). DESIGN: Evaluation of diagnostic tests and technologies. SUBJECTS: Targeted genetic panel testing for IRDs. METHODS: Data collected regarding targeted genetic panel testing for IRDs offered by different laboratories were investigated for the inclusion of coding and noncoding variants in disease genes. Both large IRD panels and smaller, more focused, disease-specific panels were included in the analysis. MAIN OUTCOME MEASURES: Number of disease genes tested as well as the commonality and uniqueness across testing platforms in both coding and noncoding variants of disease. RESULTS: Across the 3 IRD panel tests investigated, 409 unique genes are represented, of which 269 genes are tested by all 3 panels. The top 20 genes known to cause over 70% of all IRDs are represented in the 269 common genes tested by all 3 panels. In addition, 138 noncoding variants in 50 unique genes are assayed across the 3 platforms. Focused, disease-specific panels exhibit significant variability across the 5 testing platforms that were studied. CONCLUSIONS: Ordering genetic testing for IRDs is not straightforward, as evidenced by the multitude of panels available to providers. It is important that there is coverage of both coding and noncoding regions in IRD genes to offer diagnoses in these patients. This paper details the diversity of testing platforms currently available to clinicians and provides a thorough explanation of the genes tested in the different IRD panels. In a time of increased importance of the clinical genetic testing of patients with IRDs, knowledge of the proper test to order is paramount.


Subject(s)
Genetic Testing , Retinal Degeneration , Humans , Mutation , Retina
20.
Pediatr Emerg Care ; 38(3): 97-103, 2022 Mar 01.
Article in English | MEDLINE | ID: mdl-35226617

ABSTRACT

OBJECTIVES: Many adolescents use the emergency department as their sole resource for primary care and sexual health care. This provides an opportunity to prevent sexually transmitted infections and unintended pregnancy as well as to educate teenagers about their bodies and sexual health. There is no standard curriculum on sexual health as part of pediatric emergency medicine (PEM) fellowship education. Our goal is to evaluate what is taught in PEM fellowship about adolescent sexual health. METHODS: We administered an anonymous questionnaire to both PEM fellows and program directors (PDs). The questionnaire was distributed through the PEM Program Director Survey Committee. The questionnaire was sent to 88 PDs and 305 fellows total. An introductory email explaining the purpose of the study and a link to the online questionnaire was sent. The questionnaire was created using SurveyMonkey (www.surveymonkey.com). Data were analyzed using descriptive statistics. RESULTS: We achieved a 43% survey response rate from PDs (38 of 88) and a 24% survey response rate from fellows (73 of 305). The PD respondents included 61% females, and almost all (86%) are between ages 35 and 54 years. Seventy-three percent of the fellows are female, and they are all between 25 to 44 years old. There was a great deal of variability in the amount of adolescent sexual health education PDs provide their fellows in the form of lectures and bedside teaching cases. A majority of survey respondents (86% of fellows and 66% of the PDs) agreed that there should be a standard PEM curriculum to teach about adolescent sexual health. More than half (53% of PDs and 56% of fellows) are not satisfied with the number of training opportunities for adolescent sexual health. CONCLUSIONS: We found variability in adolescent sexual health training during PEM fellowship, although fellows and PDs agree that there should be a standardized curriculum. We recommend that the American Board of Pediatrics form a committee to decrease variability in the training of PEM fellows on adolescent sexual health.


Subject(s)
Emergency Medicine , Pediatric Emergency Medicine , Sexual Health , Adolescent , Adult , Child , Curriculum , Education, Medical, Graduate , Emergency Medicine/education , Fellowships and Scholarships , Female , Humans , Male , Middle Aged , Surveys and Questionnaires , United States
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