Genomics

Kishi JY, Liu N, West ER, Sheng K, Jordanides JJ, Serrata M, Cepko CL, Saka SK, Yin P. Light-Seq: light-directed in situ barcoding of biomolecules in fixed cells and tissues for spatially indexed sequencing. Nat Methods 2022;19(11):1393-1402.Abstract
We present Light-Seq, an approach for multiplexed spatial indexing of intact biological samples using light-directed DNA barcoding in fixed cells and tissues followed by ex situ sequencing. Light-Seq combines spatially targeted, rapid photocrosslinking of DNA barcodes onto complementary DNAs in situ with a one-step DNA stitching reaction to create pooled, spatially indexed sequencing libraries. This light-directed barcoding enables in situ selection of multiple cell populations in intact fixed tissue samples for full-transcriptome sequencing based on location, morphology or protein stains, without cellular dissociation. Applying Light-Seq to mouse retinal sections, we recovered thousands of differentially enriched transcripts from three cellular layers and discovered biomarkers for a very rare neuronal subtype, dopaminergic amacrine cells, from only four to eight individual cells per section. Light-Seq provides an accessible workflow to combine in situ imaging and protein staining with next generation sequencing of the same cells, leaving the sample intact for further analysis post-sequencing.
Zabaleta N, Bhatt U, Hérate C, Maisonnasse P, Sanmiguel J, Diop C, Castore S, Estelien R, Li D, Dereuddre-Bosquet N, Cavarelli M, Gallouët A-S, Pascal Q, Naninck T, Kahlaoui N, Lemaitre J, Relouzat F, Ronzitti G, Thibaut HJ, Montomoli E, Wilson JM, Le Grand R, Vandenberghe LH. Durable immunogenicity, adaptation to emerging variants, and low-dose efficacy of an AAV-based COVID-19 vaccine platform in macaques. Mol Ther 2022;30(9):2952-2967.Abstract
The COVID-19 pandemic continues to have devastating consequences on health and economy, even after the approval of safe and effective vaccines. Waning immunity, the emergence of variants of concern, breakthrough infections, and lack of global vaccine access and acceptance perpetuate the epidemic. Here, we demonstrate that a single injection of an adenoassociated virus (AAV)-based COVID-19 vaccine elicits at least 17-month-long neutralizing antibody responses in non-human primates at levels that were previously shown to protect from viral challenge. To improve the scalability of this durable vaccine candidate, we further optimized the vector design for greater potency at a reduced dose in mice and non-human primates. Finally, we show that the platform can be rapidly adapted to other variants of concern to robustly maintain immunogenicity and protect from challenge. In summary, we demonstrate this class of AAV can provide durable immunogenicity, provide protection at dose that is low and scalable, and be adapted readily to novel emerging vaccine antigens thus may provide a potent tool in the ongoing fight against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2).
Guindolet D, Woodward AM, Gabison EE, Argüeso P. Glycogene Expression Profile of Human Limbal Epithelial Cells with Distinct Clonogenic Potential. Cells 2022;11(9)Abstract
Glycans function as valuable markers of stem cells but also regulate the ability of these cells to self-renew and differentiate. Approximately 2% of the human genome encodes for proteins that are involved in the biosynthesis and recognition of glycans. In the present study, we evaluated the expression of a small subset of glycogenes in human limbal epithelial cells with distinct clonogenic potential. Individual clones were classified as abortive or clonogenic, based on the fraction of the terminal colonies produced; clones leading exclusively to terminal colonies were referred to as abortive while those with half or fewer terminal colonies were referred to as clonogenic. An analysis of glycogene expression in clonogenic cultures revealed a high content of transcripts regulating the galactose and mannose metabolic pathways. Abortive clones were characterized by increased levels of GCNT4 and FUCA2, genes that are responsible for the branching of mucin-type O-glycans and the hydrolysis of fucose residues on N-glycans, respectively. The expansion of primary cultures of human limbal epithelial cells for 10 days resulted in stratification and a concomitant increase in MUC16, GCNT4 and FUCA2 expression. These data indicate that the clonogenic potential of human limbal epithelial cells is associated with specific glycosylation pathways. Mucin-type O-glycan branching and increased fucose metabolism are linked to limbal epithelial cell differentiation.
Eraslan G, Drokhlyansky E, Anand S, Fiskin E, Subramanian A, Slyper M, Wang J, Van Wittenberghe N, Rouhana JM, Waldman J, Ashenberg O, Lek M, Dionne D, Win TS, Cuoco MS, Kuksenko O, Tsankov AM, Branton PA, Marshall JL, Greka A, Getz G, Segrè AV, Aguet F, Rozenblatt-Rosen O, Ardlie KG, Regev A. Single-nucleus cross-tissue molecular reference maps toward understanding disease gene function. Science 2022;376(6594):eabl4290.Abstract
Understanding gene function and regulation in homeostasis and disease requires knowledge of the cellular and tissue contexts in which genes are expressed. Here, we applied four single-nucleus RNA sequencing methods to eight diverse, archived, frozen tissue types from 16 donors and 25 samples, generating a cross-tissue atlas of 209,126 nuclei profiles, which we integrated across tissues, donors, and laboratory methods with a conditional variational autoencoder. Using the resulting cross-tissue atlas, we highlight shared and tissue-specific features of tissue-resident cell populations; identify cell types that might contribute to neuromuscular, metabolic, and immune components of monogenic diseases and the biological processes involved in their pathology; and determine cell types and gene modules that might underlie disease mechanisms for complex traits analyzed by genome-wide association studies.
Zhang C, Owen LA, Lillvis JH, Zhang SX, Kim IK, Deangelis MM. AMD Genomics: Non-Coding RNAs as Biomarkers and Therapeutic Targets. J Clin Med 2022;11(6)Abstract
Age-related macular degeneration (AMD) is a progressive neurodegenerative disease that is the world's leading cause of blindness in the aging population. Although the clinical stages and forms of AMD have been elucidated, more specific prognostic tools are required to determine when patients with early and intermediate AMD will progress into the advanced stages of AMD. Another challenge in the field has been the appropriate development of therapies for intermediate AMD and advanced atrophic AMD. After numerous negative clinical trials, an anti-C5 agent and anti-C3 agent have recently shown promising results in phase 3 clinical trials, in terms of slowing the growth of geographic atrophy, an advanced form of AMD. Interestingly, both drugs appear to be associated with an increased incidence of wet AMD, another advanced form of the disease, and will require frequent intravitreal injections. Certainly, there remains a need for other therapeutic agents with the potential to prevent progression to advanced stages of the disease. Investigation of the role and clinical utility of non-coding RNAs (ncRNAs) is a major advancement in biology that has only been minimally applied to AMD. In the following review, we discuss the clinical relevance of ncRNAs in AMD as both biomarkers and therapeutic targets.
Simcoe MJ, Shah A, Fan BJ, Choquet H, Weisschuh N, Waseem NH, Jiang C, Melles RB, Ritch R, Mahroo OA, Wissinger B, Jorgenson E, Wiggs JL, Garway-Heath DF, Hysi PG, Hammond CJ. Genome-Wide Association Study Identifies Two Common Loci Associated with Pigment Dispersion Syndrome/Pigmentary Glaucoma and Implicates Myopia in its Development. Ophthalmology 2022;129(6):626-636.Abstract
PURPOSE: To identify genetic variants associated with pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) in unrelated patients and to further understand the genetic and potentially causal relationships between PDS and associated risk factors. DESIGN: A 2-stage genome-wide association meta-analysis with replication and subsequent in silico analyses including Mendelian randomization. PARTICIPANTS: A total of 574 cases with PG or PDS and 52 627 controls of European descent. METHODS: Genome-wide association analyses were performed in 4 cohorts and meta-analyzed in 3 stages: (1) a discovery meta-analysis was performed in 3 cohorts, (2) replication was performed in the fourth cohort, and (3) all 4 cohorts were meta-analyzed to increase statistical power. Two-sample Mendelian randomization was used to determine whether refractive error and intraocular pressure exert causal effects over PDS. MAIN OUTCOME MEASURES: The association of genetic variants with PDS and whether myopia exerts causal effects over PDS. RESULTS: Significant association was present at 2 novel loci for PDS/PG. These loci and follow-up analyses implicate the genes gamma secretase activator protein (GSAP) (lead single nucleotide polymorphism [SNP]: rs9641220, P = 6.0×10-10) and glutamate metabotropic receptor 5 (GRM5)/TYR (lead SNP: rs661177, P = 3.9×10-9) as important factors in disease risk. Mendelian randomization showed significant evidence that negative refractive error (myopia) exerts a direct causal effect over PDS (P = 8.86×10-7). CONCLUSIONS: Common SNPs relating to the GSAP and GRM5/TYR genes are associated risk factors for the development of PDS and PG. Although myopia is a known risk factor, this study uses genetic data to demonstrate that myopia is, in part, a cause of PDS and PG.
Catomeris AJ, Ballios BG, Sangermano R, Wagner NE, Comander JI, Pierce EA, Place EM, Bujakowska KM, Huckfeldt RM. Novel RCBTB1 variants causing later-onset non-syndromic retinal dystrophy with macular chorioretinal atrophy. Ophthalmic Genet 2022;43(3):332-339.Abstract
BACKGROUND: Variants in RCBTB1 were recently described to cause a retinal dystrophy with only eight families described to date and a predominant phenotype of macular atrophy and peripheral reticular degeneration. Here, we further evaluate the genotypic and phenotypic characteristics of biallelic RCBTB1-associated retinal dystrophy in a North American clinic population. METHODS: A retrospective analysis of genetic and clinical features was performed in individuals with biallelic variants in RCBTB1. RESULTS: Three unrelated individuals of French-Canadian descent with rare biallelic RCBTB1 variants were identified. All individuals shared a novel p.(Ser342Leu) missense variant; one patient was homozygous whereas the other two each possessed a second unique novel variant p.(Gln120*) and p.(Pro224Leu). All three had macula-predominant disease with symptom onset in the fifth decade of life. CONCLUSION: This report adds to the genetic diversity of RCBTB1-associated disease. These cases confirm the later-onset, relative to many other retinal dystrophies, and macular focus of disease described in most cases to-date. They are thus a reminder of considering hereditary disease in the differential for later-onset macular atrophy.
Natera-de Benito D, Jurgens JA, Yeung A, Zaharieva IT, Manzur A, DiTroia SP, Di Gioia SA, Pais L, Pini V, Barry BJ, Chan W-M, Elder JE, Christodoulou J, Hay E, England EM, Munot P, Hunter DG, Feng L, Ledoux D, O'Donnell-Luria A, Phadke R, Engle EC, Sarkozy A, Muntoni F. Recessive variants in COL25A1 gene as novel cause of arthrogryposis multiplex congenita with ocular congenital cranial dysinnervation disorder. Hum Mutat 2022;43(4):487-498.Abstract
A proper interaction between muscle-derived collagen XXV and its motor neuron-derived receptors protein tyrosine phosphatases σ and δ (PTP σ/δ) is indispensable for intramuscular motor innervation. Despite this, thus far, pathogenic recessive variants in the COL25A1 gene had only been detected in a few patients with isolated ocular congenital cranial dysinnervation disorders. Here we describe five patients from three unrelated families with recessive missense and splice site COL25A1 variants presenting with a recognizable phenotype characterized by arthrogryposis multiplex congenita with or without an ocular congenital cranial dysinnervation disorder phenotype. The clinical features of the older patients remained stable over time, without central nervous system involvement. This study extends the phenotypic and genotypic spectrum of COL25A1 related conditions, and further adds to our knowledge of the complex process of intramuscular motor innervation. Our observations indicate a role for collagen XXV in regulating the appropriate innervation not only of extraocular muscles, but also of bulbar, axial, and limb muscles in the human.
Fote GM, Geller NR, Efstathiou NE, Hendricks N, Vavvas DG, Reidling JC, Thompson LM, Steffan JS. Isoform-dependent lysosomal degradation and internalization of apolipoprotein E requires autophagy proteins. J Cell Sci 2022;135(2)Abstract
The human apolipoprotein E4 isoform (APOE4) is the strongest genetic risk factor for late-onset Alzheimer's disease (AD), and lysosomal dysfunction has been implicated in AD pathogenesis. We found, by examining cells stably expressing each APOE isoform, that APOE4 increases lysosomal trafficking, accumulates in enlarged lysosomes and late endosomes, alters autophagic flux and the abundance of autophagy proteins and lipid droplets, and alters the proteomic contents of lysosomes following internalization. We investigated APOE-related lysosomal trafficking further in cell culture, and found that APOE from the post-Golgi compartment is degraded through autophagy. We found that this autophagic process requires the lysosomal membrane protein LAMP2 in immortalized neuron-like and hepatic cells, and in mouse brain tissue. Several macroautophagy-associated proteins were also required for autophagic degradation and internalization of APOE in hepatic cells. The dysregulated autophagic flux and lysosomal trafficking of APOE4 that we observed suggest a possible novel mechanism that might contribute to AD pathogenesis. This article has an associated First Person interview with the first author of the paper.
Brown EE, Scandura MJ, Mehrotra S, Wang Y, Du J, Pierce EA. Reduced nuclear NAD+ drives DNA damage and subsequent immune activation in the retina. Hum Mol Genet 2022;31(9):1370-1388.Abstract
Mutations in NMNAT1, a key enzyme involved in the synthesis of NAD+ in the nucleus, lead to an early onset severe inherited retinal degeneration (IRD). We aimed to understand the role of nuclear NAD+ in the retina and to identify the molecular mechanisms underlying NMNAT1-associated disease, using a mouse model that harbors the p.V9M mutation in Nmnat1 (Nmnat1V9M/V9M). We identified temporal transcriptional reprogramming in the retinas of Nmnat1V9M/V9M mice prior to retinal degeneration, which begins at 4 weeks of age, with no significant alterations in gene expression at 2 weeks of age and over 2600 differentially expressed genes by 3 weeks of age. Expression of the primary consumer of NAD+ in the nucleus, PARP1, an enzyme involved in DNA damage repair and transcriptional regulation, as well as 7 other PARP family enzymes, was elevated in the retinas of Nmnat1V9M/V9M. This was associated with elevated levels of DNA damage, PARP-mediated NAD+ consumption and migration of Iba1+/CD45+ microglia/macrophages to the subretinal space in the retinas of Nmnat1V9M/V9M mice. These findings suggest that photoreceptor cells are especially sensitive to perturbation of genome homeostasis, and that PARP-mediated cell death may play a role in other genetic forms of IRDs, and potentially other forms of neurodegeneration.
Scott HA, Larson A, Rong SS, Mehrotra S, Butcher R, Chao KR, Wiggs JL, Place EM, Pierce EA, Bujakowska KM. A hidden structural variation in a known IRD gene: a cautionary tale of two new disease candidate genes. Cold Spring Harb Mol Case Stud 2022;8(2)Abstract
Rod-cone dystrophy (RCD), also known as retinitis pigmentosa, is an inherited condition leading to vision loss, affecting 1 in 3500 people. More than 270 genes are known to be implicated in the inherited retinal degenerations (IRDs), yet genetic diagnosis for ∼30% of IRD of patients remains elusive despite advances in sequencing technologies. The goal of this study was to determine the genetic causality in a family with RCD. Family members were given a full ophthalmic exam at the Retinal Service at Massachusetts Eye and Ear and consented to genetic testing. Whole-exome sequencing (WES) was performed and variants of interest were Sanger-validated. Functional assays were conducted in zebrafish along with splicing assays in relevant cell lines to determine the impact on retinal function. WES identified variants in two potential candidate genes that segregated with disease: GNL3 (G Protein Nucleolar 3) c.1187 + 3A > C and c.1568-8C > A; and PDE4DIP (Phosphodiester 4D Interacting Protein) c.3868G > A (p.Glu1290Lys) and c.4603G > A (p.Ala1535Thr). Both genes were promising candidates based on their retinal involvement (development and interactions with IRD-associated proteins); however, the functional assays did not validate either gene. Subsequent WES reanalysis with an updated bioinformatics pipeline and widened search parameters led to the detection of a 94-bp duplication in PRPF31 (pre-mRNA Processing Factor 31) c.73_266dup (p.Asp56GlyfsTer33) as the causal variant. Our study demonstrates the importance of thorough functional characterization of new disease candidate genes and the value of reanalyzing next-generation sequencing sequence data, which in our case led to identification of a hidden pathogenic variant in a known IRD gene.
Woodward AM, Feeley MN, Rinaldi J, Argüeso P. CRISPR/Cas9 genome editing reveals an essential role for basigin in maintaining a nonkeratinized squamous epithelium in cornea. FASEB Bioadv 2021;3(11):897-908.Abstract
One of the primary functions of nonkeratinized stratified squamous epithelia is to protect underlying tissues against chemical, microbial, and mechanical insult. Basigin is a transmembrane matrix metalloproteinase inducer commonly overexpressed during epithelial wound repair and cancer but whose physiological significance in normal epithelial tissue has not been fully explored. Here we used a CRISPR/Cas9 system to study the effect of basigin loss in a human cornea model of squamous epithelial differentiation. We find that epithelial cell cultures lacking basigin change shape and fail to produce a flattened squamous layer on the apical surface. This process is associated with the abnormal expression of the transcription factor SPDEF and the decreased biosynthesis of MUC16 and involucrin necessary for maintaining apical barrier function and structural integrity, respectively. Expression analysis of genes encoding tight junction proteins identified a role for basigin in promoting physiological expression of occludin and members of the claudin family. Functionally, disruption of basigin expression led to increased epithelial cell permeability as evidenced by the decrease in transepithelial electrical resistance and increase in rose bengal flux. Overall, these results suggest that basigin plays a distinct role in maintaining the normal differentiation of stratified squamous human corneal epithelium and could have potential implications to therapies targeting basigin function.
Whitman MC, Barry BJ, Robson CD, Facio FM, Van Ryzin C, Chan W-M, Lehky TJ, Thurm A, Zalewski C, King KA, Brewer C, Almpani K, Lee JS, Delaney A, FitzGibbon EJ, Lee PR, Toro C, Paul SM, Abdul-Rahman OA, Webb BD, Jabs EW, Moller HU, Larsen DA, Antony JH, Troedson C, Ma A, Ragnhild G, Wirgenes KV, Tham E, Kvarnung M, Maarup TJ, MacKinnon S, Hunter DG, Collins FS, Manoli I, Engle EC. TUBB3 Arg262His causes a recognizable syndrome including CFEOM3, facial palsy, joint contractures, and early-onset peripheral neuropathy. Hum Genet 2021;140(12):1709-1731.Abstract
Microtubules are formed from heterodimers of alpha- and beta-tubulin, each of which has multiple isoforms encoded by separate genes. Pathogenic missense variants in multiple different tubulin isoforms cause brain malformations. Missense mutations in TUBB3, which encodes the neuron-specific beta-tubulin isotype, can cause congenital fibrosis of the extraocular muscles type 3 (CFEOM3) and/or malformations of cortical development, with distinct genotype-phenotype correlations. Here, we report fourteen individuals from thirteen unrelated families, each of whom harbors the identical NM_006086.4 (TUBB3):c.785G>A (p.Arg262His) variant resulting in a phenotype we refer to as the TUBB3 R262H syndrome. The affected individuals present at birth with ptosis, ophthalmoplegia, exotropia, facial weakness, facial dysmorphisms, and, in most cases, distal congenital joint contractures, and subsequently develop intellectual disabilities, gait disorders with proximal joint contractures, Kallmann syndrome (hypogonadotropic hypogonadism and anosmia), and a progressive peripheral neuropathy during the first decade of life. Subsets may also have vocal cord paralysis, auditory dysfunction, cyclic vomiting, and/or tachycardia at rest. All fourteen subjects share a recognizable set of brain malformations, including hypoplasia of the corpus callosum and anterior commissure, basal ganglia malformations, absent olfactory bulbs and sulci, and subtle cerebellar malformations. While similar, individuals with the TUBB3 R262H syndrome can be distinguished from individuals with the TUBB3 E410K syndrome by the presence of congenital and acquired joint contractures, an earlier onset peripheral neuropathy, impaired gait, and basal ganglia malformations.
Mychaleckyj J, Valo E, Ichimura T, Ahluwalia T, Dina C, Miller R, Shabalin I, Gyorgy B, Cao J, Onengut-Gumuscu S, Satake E, Smiles A, Haukka J, Tregouet D-A, Costacou T, O'Neil K, Paterson A, Forsblom C, Keenan H, Pezzolesi M, Pragnell M, Galecki A, Rich S, Sandholm N, Klein R, Klein B, Susztak K, Orchard T, Korstanje R, King G, Hadjadj S, Rossing P, Bonventre J, Groop P-H, Warram J, Krolewski A. Association of Coding Variants in Hydroxysteroid 17-beta Dehydrogenase 14 (HSD17B14) with Reduced Progression to End Stage Kidney Disease in Type 1 Diabetes. J Am Soc Nephrol 2021;Abstract
BACKGROUND: Rare variants in gene coding regions likely have a greater impact on disease-related phenotypes than common variants through disruption of their encoded protein. We searched for rare variants associated with onset of end stage kidney disease (ESKD) in individuals with type 1 diabetes at advanced kidney disease stage. METHODS: Gene-based exome array analysis of 15,449 genes in 5 large incidence cohorts of individuals with type 1 diabetes and proteinuria were analyzed for survival time-to-ESKD, testing the top gene in a 6th cohort (N=2,372/1,115 events all cohorts) and replicating in two retrospective case-control studies (N=1,072 cases, 752 controls). Deep resequencing of the top associated gene in 5 cohorts confirmed the findings. We performed immunohistochemistry and gene expression experiments in human control and diseased cells, and in mouse ischemia reperfusion and aristolochic acid nephropathy models. RESULTS: Protein coding variants in the hydroxysteroid 17-beta dehydrogenase 14 gene (HSD17B14), predicted to affect protein structure, had a net protective effect against development of ESKD at exome-wide significance (N=4,196; p-value=3.3x10-7). The HSD17B14 gene and encoded enzyme were robustly expressed in healthy human kidney, maximally in proximal tubular cells. Paradoxically, gene and protein expression were attenuated in human diabetic proximal tubules and in mouse kidney injury models. Expressed HSD17B14 gene and protein levels remained low without recovery after 21 days in a murine ischemic reperfusion injury model. Decreased gene expression was found in other chronic kidney disease-associated renal pathologies. CONCLUSIONS: HSD17B14 gene is mechanistically involved in diabetic kidney disease. The encoded sex steroid enzyme is a druggable target, potentially opening a new avenue for therapeutic development.
Sangermano R, Deitch I, Peter VG, Ba-Abbad R, Place EM, Zampaglione E, Wagner NE, Fulton AB, Coutinho-Santos L, Rosin B, Dunet V, AlTalbishi A'a, Banin E, Sousa AB, Neves M, Larson A, Quinodoz M, Michaelides M, Ben-Yosef T, Pierce EA, Rivolta C, Webster AR, Arno G, Sharon D, Huckfeldt RM, Bujakowska KM. Broadening INPP5E phenotypic spectrum: detection of rare variants in syndromic and non-syndromic IRD. NPJ Genom Med 2021;6(1):53.Abstract
Pathogenic variants in INPP5E cause Joubert syndrome (JBTS), a ciliopathy with retinal involvement. However, despite sporadic cases in large cohort sequencing studies, a clear association with non-syndromic inherited retinal degenerations (IRDs) has not been made. We validate this association by reporting 16 non-syndromic IRD patients from ten families with bi-allelic mutations in INPP5E. Additional two patients showed early onset IRD with limited JBTS features. Detailed phenotypic description for all probands is presented. We report 14 rare INPP5E variants, 12 of which have not been reported in previous studies. We present tertiary protein modeling and analyze all INPP5E variants for deleteriousness and phenotypic correlation. We observe that the combined impact of INPP5E variants in JBTS and non-syndromic IRD patients does not reveal a clear genotype-phenotype correlation, suggesting the involvement of genetic modifiers. Our study cements the wide phenotypic spectrum of INPP5E disease, adding proof that sequence defects in this gene can lead to early-onset non-syndromic IRD.

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