Publications

2017

Whole-brain networks derived from diffusion tensor imaging (DTI) data require the identification of seed and target regions of interest (ROIs) to assess connectivity patterns. This study investigated how initiating tracts from gray matter (GM) or white matter (WM) seed ROIs impacts (1) structural networks constructed from DTI data from healthy elderly (control) and individuals with Alzheimer's disease (AD) and (2) between-group comparisons using these networks. DTI datasets were obtained from the Alzheimer's disease Neuroimaging Initiative database. Deterministic tractography was used to build two whole-brain networks for each subject; one in which tracts were initiated from WM ROIs and another in which they were initiated from GM ROIs. With respect to the first goal, in both groups, WM-seeded networks had approximately 400 more connections and stronger connections (as measured by number of streamlines per connection) than GM-seeded networks, but shared 94% of the connections found in the GM-seed networks. With respect to the second goal, between-group comparisons revealed a stronger subnetwork (as measured by number of streamlines per connection) in controls compared to AD using both WM-seeded and GM-seeded networks. The comparison using WM-seeded networks produced a larger (i.e., a greater number of connections) and more significant subnetwork in controls versus AD. Global, local, and nodal efficiency were greater in controls compared to AD, and between-group comparisons of these measures using WM-seeded networks had larger effect sizes than those using GM-seeded networks. These findings affirm that seed location significantly affects the ability to detect between-group differences in structural networks.

Zhao J, Chen W, Huang X, Peng S, Zhu T, Deng Z, Liang P, Chang H, Fan BJ. Serum Th1 and Th17 related cytokines and autoantibodies in patients with Posner-Schlossman syndrome. PLoS One. 2017;12(4):e0175519.

Posner-Schlossman syndrome (PSS) shares some clinical features with uveitis and open angle glaucoma. Cytokines and autoantibodies have been associated with uveitis and open angle glaucoma. However, the role of serum cytokines and autoantibodies in the pathogenesis of PSS remains unknown. This study aimed to evaluate the associations of type 1 T helper (Th1) and Th17 related cytokines and autoantibodies with PSS. Peripheral blood serum samples were collected from 81 patients with PSS and 97 gender- and age-matched healthy blood donors. Th1 and Th17 related cytokines, including interleukin-1β (IL-1β), IL-12, tumor necrosis factor-α (TNF-α), interferon- γ (IFN-γ), IL-6 and IL-17, and glucose-6-phosphate isomerase (GPI) were determined by double antibody sandwich ELISA. Anti-nuclear antibody (ANA), anti-keratin antibody (AKA) and anti-neutrophil cytoplasmic antibody (ANCA) were detected by indirect immunofluorescence assay. Anti-cardiolipin antibody (ACA)-IgG, ACA-IgM, ACA-IgA, anti-double stranded DNA (anti-dsDNA) and anti-cyclic citrullinated peptide antibody (anti-CCP) were detected by indirect ELISA. Serum levels of IL-1β, IL-12 and IL-6 in PSS patients were significantly lower than those in controls (P < 0.003), and these associations survived the Bonferroni correction (Pc < 0.018). There was no significant difference in serum levels of TNF-α, IFN-γ and IL-17 between the PSS and control groups (Pc > 0.12). Positive rate of serum anti-dsDNA in PSS patients was significantly higher than that in the control group (P = 0.002, Pc = 0.018), while positive rates of serum ANA, AKA, ANCA, ACA-IgG, ACA-IgM, ACA-IgA, GPI and anti-CCP in the PSS group were not significantly different from those in the control group (Pc > 0.09). These results suggest that anti-dsDNA may contribute to the pathogenesis of PSS, while Th1 and Th17 related cytokines and other autoantibodies may not be major contributors to PSS.

Ramke M, Lee JY, Dyer D, Seto D, Rajaiya J, Chodosh J. The 5’UTR in human adenoviruses: leader diversity in late gene expression. Sci Rep. 2017;7(1):618.

Human adenoviruses (HAdVs) shut down host cellular cap-dependent mRNA translation while initiating the translation of viral late mRNAs in a cap-independent manner. HAdV 5' untranslated regions (5'UTRs) are crucial for cap-independent initiation, and influence mRNA localization and stability. However, HAdV translational regulation remains relatively uncharacterized. The HAdV tripartite leader (TPL), composed of three introns (TPL 1-3), is critical to the translation of HAdV late mRNA. Herein, we annotated and analyzed 72 HAdV genotypes for the HAdV TPL and another previously described leader, the i-leader. Using HAdV species D, type 37 (HAdV-D37), we show by reverse transcription PCR and Sanger sequencing that mRNAs of the HAdV-D37 E3 transcription unit are spliced to the TPL. We also identified a polycistronic mRNA for RID-α and RID-β. Analysis of the i-leader revealed a potential open reading frame within the leader sequence and the termination of this potential protein in TPL3. A potential new leader embedded within the E3 region was also detected and tentatively named the j-leader. These results suggest an underappreciated complexity of post-transcriptional regulation, and the importance of HAdV 5'UTRs for precisely coordinated viral protein expression along the path from genotype to phenotype.

PURPOSE: To describe the clinical course, surgical experience, and postoperative outcomes of 3 patients with Fuchs endothelial dystrophy who underwent Descemet membrane endothelial keratoplasty (DMEK) after failed Descemet stripping without endothelial keratoplasty. METHODS: Three patients who underwent DMEK for management of persistent corneal edema after deliberate Descemet stripping in the setting of Fuchs endothelial dystrophy were identified. Patients were examined at day 1, week 1, and months 1, 3, and 6 after DMEK. Visual acuity, central corneal thickness (CCT), and evaluation of central corneal endothelial cell counts were recorded. RESULTS: Two women and one man, aged 56, 72, and 68 years, were included. The time interval between primary Descemet stripping and DMEK ranged from 3.5 to 8 months. Preoperative visual acuities were 20/200, 20/300, and 20/80. Immediately before DMEK, no patients had countable central endothelial cells, and CCTs were 825, 1034, and 878 μm. After DMEK, all patients had improvement in visual acuity to 20/70, 20/20, and 20/20 with CCTs of 529, 504, and 528. The postoperative period in the first case was notable for the immediate development of a pigmented pupillary membrane with posterior synechiae, as well as cystoid macular edema, of uncertain chronicity, noted 1 month postoperatively. The second case also developed posterior synechiae. Two cases completed 6-month endothelial cell counts totaling 2200 and 3114 cells per square millimeter (endothelial cell loss of 13% and 5.3%). CONCLUSIONS: DMEK is a reliable procedure to facilitate corneal rehabilitation and visual recovery in the event of poor corneal clearance after Descemet stripping without endothelial keratoplasty.
Roohipoor R, Yaseri M, Teymourpour A, Kloek C, Miller J, Loewenstein J. Early Performance on an Eye Surgery Simulator Predicts Subsequent Resident Surgical Performance. J Surg Educ. 2017;

OBJECTIVE: To examine early performance on an eye surgery simulator and its relationship to subsequent live surgical performance in a single large residency program. DESIGN: Retrospective study. SETTING: Massachusetts Eye and Ear, Harvard Medical School, Department of Ophthalmology. METHODS: In a retrospective study, we compared performance of 30 first-year ophthalmology residents on an eye surgery simulator to their surgical skills as third-year residents. Variables collected from the eye surgery simulator included scores on the following modules of the simulator (Eyesi, VRmagic, Mannheim, Germany): antitremor training level 1, bimanual training level 1, capsulorhexis level 1 (configured), forceps training level 1, and navigation training level 1. Subsequent surgical performance was assessed using the total number of phacoemulsification cataract surgery cases for each resident, as well as the number performed as surgeon during residency and scores on global rating assessment of skills in intraocular surgery (GRASIS) scales during the third year of residency. Spearman correlation coefficients were calculated between each of the simulator performance and subsequent surgical performance variables. We also compared variables in a small group of residents who needed extra help in learning cataract surgery to the other residents in the study. MAIN OUTCOME MEASURES: Relationships between Eyesi scores early in residency and surgical performance measures in the final year of residency. RESULTS: A total of 30 residents had Eyesi data from their first year of residency and had already graduated so that all subsequent surgical performance data were available. There was a significant correlation between capsulorhexis task score on the simulator and total surgeries (r = 0.745, p = 0.008). There was a significant correlation between antitremor training level 1 (r = 0.554, p = 0.040), and forceps training level 1 (r = 0.622, p = 0.023) with primary surgery numbers. There was a significant correlation between forceps training level 1 (r = 0.811, p = 0.002), and navigation training level 1 (r = 0.692, p =0.013) with total GRASIS score. There was a significant inverse correlation between total GRASIS score and residents in need of extra help (r = -0.358, p =0.003). CONCLUSION: Module scores on an eye surgery simulator early in residency may predict a resident׳s future performance in the operating room. These scores may allow early identification of residents in need of supplemental training in cataract surgery.

Saavedra J, Schwartzman J, Gilmore M. Mapping Transposon Insertions in Bacterial Genomes by Arbitrarily Primed PCR. Curr Protoc Mol Biol. 2017;118:15.15.1–15.15.15.

Transposons can be used to easily generate and label the location of mutations throughout bacterial and other genomes. Transposon insertion mutants may be screened for a phenotype as individual isolates, or by selection applied to a pool of thousands of mutants. Identifying the location of a transposon insertion is critical for connecting phenotype to the genetic lesion. In this unit, we present an easy and detailed approach for mapping transposon insertion sites using arbitrarily-primed PCR (AP-PCR). Two rounds of PCR are used to (1) amplify DNA spanning the transposon insertion junction, and (2) increase the specific yield of transposon insertion junction fragments for sequence analysis. The resulting sequence is mapped to a bacterial genome to identify the site of transposon insertion. In this protocol, AP-PCR as it is routinely used to map sites of transposon insertion within Staphylococcus aureus, is used to illustrate the principle. Guidelines are provided for adapting this protocol for mapping insertions in other bacterial genomes. Mapping transposon insertions using this method is typically achieved in 2 to 3 days if starting from a culture of the transposon insertion mutant. © 2017 by John Wiley & Sons, Inc.

Spencer C, Abend S, McHugh K, Saint-Geniez M. Identification of a synergistic interaction between endothelial cells and retinal pigment epithelium. J Cell Mol Med. 2017;21(10):2542–2552.
The retinal pigment epithelium located between the neurosensory retina and the choroidal vasculature is critical for the function and maintenance of both the photoreceptors and underlying capillary endothelium. While the trophic role of retinal pigment epithelium on choroidal endothelial cells is well recognized, the existence of a reciprocal regulatory function of endothelial cells on retinal pigment epithelium cells remained to be fully characterized. Using a physiological long-term co-culture system, we determined the effect of retinal pigment epithelium-endothelial cell heterotypic interactions on cell survival, behaviour and matrix deposition. Human retinal pigment epithelium and endothelial cells were cultured on opposite sides of polyester transwells for up to 4 weeks in low serum conditions. Cell viability was quantified using a trypan blue assay. Cellular morphology was evaluated by H&E staining, S.E.M. and immunohistochemistry. Retinal pigment epithelium phagocytic function was examined using a fluorescent bead assay. Gene expression analysis was performed on both retinal pigment epithelium and endothelial cells by quantitative PCR. Quantification of extracellular matrix deposition was performed on decellularized transwells stained for collagen IV, fibronectin and fibrillin. Our results showed that presence of endothelial cells significantly improves retinal pigment epithelium maturation and function as indicated by the induction of visual cycle-associated genes, accumulation of a Bruch's membrane-like matrix and increase in retinal pigment epithelium phagocytic activity. Co-culture conditions led to increased expression of anti-angiogenic growth factors and receptors in both retinal pigment epithelium and endothelial cells compared to monoculture. Tube-formation assays confirmed that co-culture with retinal pigment epithelium significantly decreased the angiogenic phenotype of endothelial cells. These findings provide evidence of critical interdependent interactions between retinal pigment epithelium and endothelial cell involved in the maintenance of retinal homeostasis.
Reactive remodeling of optic nerve head astrocytes is consistently observed in glaucoma and other optic nerve injuries. However, it is unknown whether this reactivity is beneficial or harmful for visual function. In this study, we used the Cre recombinase (Cre)-loxP system under regulation of the mouse glial fibrillary acidic protein promoter to knock out the transcription factor signal transducer and activator of transcription 3 (STAT3) from astrocytes and test the effect this has on reactive remodeling, ganglion cell survival, and visual function after experimental glaucoma and nerve crush. After injury, STAT3 knockout mice displayed attenuated astrocyte hypertrophy and reactive remodeling; astrocytes largely maintained their honeycomb organization and glial tubes. These changes were associated with increased loss of ganglion cells and visual function over a 30-day period. Thus, reactive astrocytes play a protective role, preserving visual function. STAT3 signaling is an important mediator of various aspects of the reactive phenotype within optic nerve astrocytes.

The use of viral vectors for inner ear gene therapy is receiving increased attention for treatment of genetic hearing disorders. Most animal studies to date have injected viral suspensions into neonatal ears, via the round window membrane. Achieving transduction of hair cells, or sensory neurons, throughout the cochlea has proven difficult, and no studies have been able to efficiently transduce sensory cells in adult ears while maintaining normal cochlear function. Here, we show, for the first time, successful transduction of all inner hair cells and the majority of outer hair cells in an adult cochlea via virus injection into the posterior semicircular canal. We used a "designer" AAV, AAV2/Anc80L65, in which the main capsid proteins approximate the ancestral sequence state of AAV1, 2, 8, and 9. Our injections also transduced ~10% of spiral ganglion cells and a much larger fraction of their satellite cells. In the vestibular sensory epithelia, the virus transduced large numbers of hair cells and virtually all the supporting cells, along with close to half of the vestibular ganglion cells. We conclude that this viral vector and this delivery route hold great promise for gene therapy applications in both cochlear and vestibular sense organs.

Antigen-presenting cells (APCs) play an important role in transplant rejection and tolerance. In high-risk corneal transplantation, where the graft bed is inflamed and vascularized, immature APCs in the donor corneal stroma quickly mature and migrate to lymphoid tissues to sensitize host T cells. In this study, using a mouse model of corneal transplantation, we investigated whether enrichment of tolerogenic APCs (tolAPCs) in donor corneas can enhance graft survival in corneal allograft recipients with inflamed graft beds. Treatment of donor corneas with interleukin-10 (IL-10) and transforming growth factor-β1 (TGFβ1) altered the phenotype and function of tissue-residing APCs. Transplantation of these tolAPC-enriched corneas decreased frequencies of interferon gamma (IFNγ)(+) effector T cells (Teffs), as well as allosensitization in the hosts, diminished graft infiltration of CD45(+) and CD4(+) cells, and significantly improved corneal allograft survival compared to saline-injected controls. These data provide a novel approach for tolAPC-based immunotherapy in transplantation by direct cytokine conditioning of the donor tissue.