Thiazolide Prodrug Esters and Derived Peptides: Synthesis and Activity

Amino acid ester prodrugs of the thiazolides, introduced to improve the pharmacokinetic parameters of the parent drugs, proved to be stable as their salts but were unstable at pH > 5. Although some of the instability was due to simple hydrolysis, we have found that the main end products of the degradation were peptides formed by rearrangement. These peptides were stable solids: they maintained significant antiviral activity, and in general, they showed improved pharmacokinetics (better solubility and reduced clearance) compared to the parent thiazolides. We describe the preparation and evaluation of these peptides.

O-216 CRISPR/Cas9 mediated knock-out (KO) reveals a divergent role for trophectoderm markers GATA2/3 in the mouse and human preimplantation embryo

Study question

What is the effect of CRISPR/Cas9-mediated KO of trophectoderm (TE) markers GATA2/3 on embryo development and lineage commitment in both mouse and human preimplantation embryos?

Summary answer

CRISPR/Cas9-mediated KO of GATA2/3 points to interspecies differences in TE regulation and potential cross-talk between trophectoderm and inner cell mass (ICM) in mouse preimplantation embryos.

What is known already

GATA3 and its isoform GATA2 are major TE markers regulating the first lineage segregation, operating downstream of the HIPPO-pathway. Although recent evidence suggests that the HIPPO-pathway is conserved across mouse and human, it is unknown whether GATA2/3 share similar interspecies function during preimplantation development. GATA3 RNA depletion experiments in mouse embryos revealed a compensatory upregulation of GATA2, that potentially masked the observed phenotype. Upon double KO (DKO), the phenotype appeared more severe, as embryos were unable to cavitate. However, the precise effect of the (D)KO on embryo development was not investigated thoroughly, and should be expanded towards human preimplantation embryos.

Study design, size, duration

Mouse embryonic stem cells (mESCs), mouse zygotes and donated human spare oocytes were targeted. CRISPR/Cas9 ribonucleoprotein complexes, either targeting Gata3/GATA3, Gata2 or both, were delivered via nucleofection, electroporation or co-injected with sperm, in mESCs, mouse zygotes or human oocytes, respectively. Appropriate non-targeted control groups were included. Morphological analysis, immunofluorescence and next-generation sequencing were applied to check for gene editing efficiency and the impact of KO on embryonic development.

Participants/materials, setting, methods

The targeted embryos and controls were cultured for 4.5 (mouse) or 6.5 days (human) in vitro. They were stained for different developmental markers, including TEAD4 and CDX2 (TE), OCT4 and SOX2 (early ICM), NANOG (epibast, EPI) and SOX17 (hypoblast, PrE). Immunostaining was used to determine cell number, TE/ICM fraction, marker localization and fluorescence intensity. Embryos were subjected to genetic analysis to determine on-target efficiency, while in silico predicted off-target sites were evaluated in targeted mESCs.

Main results and the role of chance

GATA3 KO mouse embryos exhibited morula arrest (94%; n = 16). All GATA3-edited mouse embryos exhibited a reduction of CDX2-positive cells. From the 12 full KO embryos, four showed a decreased number of NANOG-positive blastomeres. No effect was observed for TEAD4 and OCT4. Complete KO morulas were devoid of SOX2 expression.

GATA2 KO mouse embryos could still form blastocysts (19% morula arrest, n = 21 embryos), even when harboring 100% frameshift mutations. KO did not noticeably influence cell number nor the expression of GATA3 or NANOG.

GATA2/3 DKO mouse embryos could still form blastocysts (38% morula arrest, n = 21), showing a milder phenotype compared to GATA3 KO embryos. In the presumed DKO blastocysts, the whole ICM is NANOG-positive and increased in cell number. SOX2 expression was still retained in the ICM, but presumed polar TE was also SOX2-positive.

Three out of four GATA3 KO human embryos harboring 100% frameshift mutations, were surprisingly able to form blastocysts. In one embryo, no morphological TE could be formed, while the others showed one or two CDX2-positive cells in TE. No effect was observed for TEAD4 and OCT4. In addition, all KO embryos displayed an increase in ICM/TE fraction. Some outer cells in KO blastocysts were NANOG-positive.

Limitations, reasons for caution

CRISPR/Cas9 is limited by the occurrence of mosaicism (more than one genotype present in an embryo) and potential off-target editing, which we will assess at in silico predicted off-target sites via NGS in mESCs. The observations of the study will be consolidated by increasing the sample size, especially in human.

Wider implications of the findings

Gene editing studies enable us to unravel the molecular interactions that are required for human preimplantation development. Obtaining novel insights into the molecular networks of the GATA transcription factor family could significantly improve our understanding of several pregnancy-related complications related to trophectoderm specification, such as early miscarriage or preeclampsia.

Trial registration number

NA

Correction to: Assessing Improvement of Patient Satisfaction Following Facelift Surgery Using the FACE-Q Scales: A Prospective and Multicenter Study

The Electronic Supplementary Material originally published with this article has been removed due to lack of appropriate permissions from the copyright holder.

Current status of surgical planning and transfer methods in orthognathic surgery

Since the advent of orthognathic surgery major efforts have been made to render these surgical procedures more reliable, accurate, reproducible, and shorter. Such improvements imply the enhancement of surgical planning (SP) techniques and optimization of SP transfer tools. Most widespread current SP methods are based on physical examination/anthropometric measurements combined with cephalometric analysis. Most surgeons currently use handmade acrylic surgical splints or sometimes freehand surgery as transfer tool. The emergence of virtual surgical planning (VSP) procedures gave birth to several modern transfer tools, such as computer-assisted design and manufactured (CAD/CAM) splints, CAD/CAM splints with extra-oral bone support, customized miniplates, and surgical navigation. This article classifies and describes these emerging transfer tools, therewith underlining their advantages and drawbacks.

Performance of Pyridylthiourea-Polyethylenimine Polyplex for siRNA-Mediated Liver Cancer Therapy in Cell Monolayer, Spheroid, and Tumor Xenograft Models

Medical application of siRNAs relies on methods for delivering nucleic acids into the cytosol. Synthetic carriers, which assemble with nucleic acids into delivery systems, show promises for cancer therapy but efficiency remains to be improved. In here, the effectiveness of pyridylthiourea-polyethylenimine (πPEI), a siRNA carrier that favors both polyplex disassembly and endosome rupture upon sensing the acidic endosomal environment, in 3 experimental models of hepatocellular cancer is tested. The πPEI-assisted delivery of a siRNA targeting the polo-like kinase 1 into Huh-7 monolayer produces a 90% cell death via a demonstrated RNA interference mechanism. Incubation of polyplex with Huh-7 spheroids leads to siRNA delivery into the superficial first cell layer and a 60% reduction in spheroid growth compared to untreated controls. Administration of polyplexes into mice bearing subcutaneous implanted Huh-7Luc tumors results in a reduced tumor progression, similar to the one observed in the spheroid model. Altogether, these results support the in vivo use of synthetic and dedicated polymers for increasing siRNA-mediated gene knockdown, and their clinical promise in cancer therapeutics.

Clinical grading of the upper palpebral conjunctiva of non-contact lens wearers

PURPOSE

To categorize the appearance of the normal upper palpebral conjunctiva using a grading scale and to investigate interobserver agreement with a grading scale modified to include decimal increments.

METHODS

Upper palpebral conjunctival appearance of 96 non-contact lens wearing subjects aged 18 to 75 years was assessed using a photographic grading scale that has a generic (zero to four) scale to score redness and roughness of the palpebral conjunctiva.

RESULTS

Median redness and roughness was about 1.25 units. About 5% of subjects had redness or roughness >2.0 units. Interobserver agreement improved during the study. By the end of the study, the standard deviation of the discrepancy scores was 0.12 to 0.19 units.

CONCLUSIONS

Upper palpebral conjunctival redness or roughness >2.0 units are unusual. The grading scale can be used successfully with decimal rather than integer scale increments. For experienced clinicians, a change in grade of > or =0.5 units may be significant.

Visual-proprioceptive mapping in children with developmental coordination disorder

Developmental coordination disorder (DCD) occurs in a small but significant proportion of children who present with impaired body-eye coordination and show poor acquisition of motor skills. This study investigated the visual-proprioceptive mapping ability of children with DCD from a small selected group, with particular reference to the use of vision in matching tasks. The children with DCD in this study were significantly poorer than control children on all matching tasks. They seemed to have particular difficulty in cross-modal judgements that required the use of visual information to guide proprioceptive judgements of limb position. A distinction is drawn between tasks that can be achieved purely through sensory matching and those that require body-centred spatial judgements, suggesting that it is the latter that posits a particular difficulty for children with DCD.

Eye movements, prematurity and developmental co-ordination disorder

Horizontal pursuit eye movements were investigated in two separate groups of children: One group exhibited developmental co-ordination disorder (n = 8) whilst another group of children were born prematurely (n = 8). Both studies found a reduced gain in pursuit eye movements when the respective populations were compared with control groups (n = 32). A difference was also found in the ability of some children to temporally synchronize their tracking response to the stimulus, which was indicative of poor predictive control rather than lags in the control system. We suggest that horizontal eye movements may be a sensitive indicator of more general motor deficits during childhood development.

Visual evoked potentials in children with developmental coordination disorder

Children who demonstrate problems with skilled movement in the absence of physical handicap are formally designated as suffering from developmental coordination disorder (DCD). Diagnosis of DCD was confirmed by the 'movement assessment battery for children'. Visually evoked potentials (VEPs) were recorded to evaluate the integrity of the visual pathway and to rule out the presence of any neurological lesions affecting visual input. Binocular, pattern onset VEPs were recorded in 14 children with DCD aged between five and seven years, and an age-matched control group using pattern onset, high contrast, grating stimuli. Implicit times to the first and second peaks and troughs were measured, and results between the two groups were compared. Inattention and movement artefact meant that VEPs were more difficult to record within the DCD group, resulting in smaller amplitudes of the waveform, but no significant differences in the implicit times were observed between the DCD group and controls. Further research is required to determine the specific source of the neurological deficits in DCD but a problem with the integrity of the afferent visual pathway does not appear to be a causal factor.

Contour interaction in the presence of congenital nystagmus

Using a computer-generated acuity task, the resolution of vertical and horizontal Landolt Cs was assessed at three levels of contrast, each for three different crowding conditions. Eighteen adults participated; six had congenital idiopathic nystagmus, six were oculocutaneous albinos and six served as controls. Contour interaction was evident when bars were placed 1 gap-width from the Landolt C and was more marked as contrast increased. When scaled to the individual resolution limit, the magnitude of contour interaction displayed by the albinos was not significantly different from the controls, however the idiopaths did exhibit a greater crowding effect than the controls. These results imply that fixation instability is a contributory factor in contour interaction, but only when retinal image velocity is above a certain threshold.

Both bipartite geminivirus movement proteins define viral host range, but only BL1 determines viral pathogenicity

Bipartite geminiviruses such as squash leaf curl virus (SqLCV) encode two movement proteins (MPs), BR1 and BL1, that are essential for virus movement and systemic infection of host plants. BR1 has been implicated in the host range properties of the virus, and BL1 in viral pathogenic properties. To more precisely examine the roles of each MP, we have introduced missense and deletion mutations into the coding sequence of both BR1 and BL1, and examined the effects of these mutations on viral infectivity and the production of disease symptoms in pumpkin, squash, and Nicotiana benthamiana. For each MP, a range of mutant phenotypes from partially to fully defective was observed that affected the overall level and rate of infectivity. However, only mutations in BL1, and not BR1, affected the severity of disease symptoms, confirming our earlier finding that BL1 is responsible for the production of disease symptoms. For all mutants, the cucurbit hosts were found to be more permissive for viral movement than was N. benthamiana, and several mutations in both BL1 and BR1 produced host-specific phenotypes, retaining high levels of infectivity in pumpkin and squash, but abolishing infectivity for N. benthamiana. Unexpectedly, functional SqLCV coat protein (AR1) was found to specifically mask the phenotypes of certain BR1 mutations, suggesting some redundancy of function between coat protein and the BR1 MP and an interaction of AR1 with the viral movement pathway. AR1 and BR1 have similar nucleic acid binding affinities, suggesting a possible mechanism for the observed effects of the viral coat protein on viral movement.

Periodic alternating nystagmus in humans with albinism

PURPOSE

To quantify the spatial and temporal nature of congenital periodic alternating nystagmus (PAN) and to test the hypothesis that PAN results from a temporal shift in the null zone.

METHODS

Twenty-five subjects with oculocutaneous albinism (16 tyrosinase negative and 9 tyrosinase positive) and 7 with ocular albinism (5 x-linked and 2 autosomal recessive) participated in the study. Using infrared oculography, five features of the nystagmus were examined: amplitude, frequency, waveform, beat direction, and temporal nature of the cycle.

RESULTS

Twelve subjects (37.5%) exhibited a PAN. The nystagmus waveforms encountered during the PAN active phases were either jerk-with-extended-foveation or pseudocycloid, whereas a variety of oscillations (including triangular and bidirectional) were evident during the quiet phases. For most of the 12 subjects, there was an asymmetric variation in nystagmus intensity during each PAN cycle. None of the 12 demonstrated a convergence null or an abnormal head posture.

CONCLUSIONS

PAN is not an uncommon oscillation among humans with albinism. Changes in gaze position markedly influenced the periodicity of the ongoing nystagmus, thus supporting the hypothesis that PAN is the result of a temporal shift in the null zone.

An interaction between the DNA-binding domains of RelA(p65) and Sp1 mediates human immunodeficiency virus gene activation

Induction of human immunodeficiency virus type 1 (HIV-1) gene expression in stimulated T cells has been attributed to the activation of the transcription factor NF-kappa B. The twice-repeated kappa B sites within the HIV-1 long terminal repeat are in close proximity to three binding sites for Sp1. We have previously shown that a cooperative interaction of NF-kappa B with Sp1 is required for the efficient stimulation of HIV-1 transcription. In this report, we define the domains of each protein responsible for this effect. Although the transactivation domains seemed likely to mediate this interaction, we find, surprisingly, that this interaction occurs through the putative DNA-binding domains of both proteins. Sp1 specifically interacted with the amino-terminal region of RelA(p65). Similarly, RelA bound directly to the zinc finger region of Sp1. This interaction was specific and resulted in cooperative DNA binding to the kappa B and Sp1 sites in the HIV-1 long terminal repeat. Furthermore, the amino-terminal region of RelA did not associate with several other transcription factors, including MyoD, E12, or Kox15, another zinc finger protein. These findings suggest that the juxtaposition of DNA-binding sites promotes a specific protein interaction between the DNA-binding regions of these transcription factors. This interaction is required for HIV transcriptional activation and may provide a mechanism to allow for selective activation of kappa B-regulated genes.

The geminivirus BR1 movement protein binds single-stranded DNA and localizes to the cell nucleus

Plant viruses encode movement proteins that are essential for infection of the host but are not required for viral replication or encapsidation. Squash leaf curl virus (SqLCV), a bipartite geminivirus with a single-stranded DNA genome, encodes two movement proteins, BR1 and BL1, that have been implicated in separate functions in viral movement. To further elucidate these functions, we have investigated the nucleic acid binding properties and cellular localization of BR1 and BL1. In this study, we showed that BR1 binds strongly to single-stranded nucleic acids, with a higher affinity for single-stranded DNA than RNA, and is localized to the nucleus of SqLCV-infected plant cells. In contrast, BL1 binds only weakly to single-stranded nucleic acids and not at all to double-stranded DNA. The nuclear localization of BR1 and the previously demonstrated plasma membrane localization of BL1 were also observed when these proteins were expressed from baculovirus vectors in Spodoptera frugiperda insect cells. The biochemical properties and cellular locations of BR1 and BL1 suggest a model for SqLCV movement whereby BR1 is involved in the shuttling of the genome in and/or out of the nucleus and BL1 acts at the plasma membrane/cell wall to facilitate viral movement across cell boundaries.

Ocular motor behaviour of monozygotic twins with tyrosinase negative oculocutaneous albinism

The involuntary nystagmus movements of 16-year-old monozygotic twins with tyrosinase negative oculocutaneous albinism were examined. On primary gaze both girls exhibited bilateral conjugate horizontal nystagmus, a jerk with extended foveation waveform, and similar frequencies (2.0 Hz:1.9 Hz), although the fast phases were in opposite directions. The mean amplitudes differed markedly (6.8 degrees:3.7 degrees), as did the position of the null zones (+20 degrees to +30 degrees:-25 degrees to -35 degrees) and the widths of the neutral zones (-25 degrees to +20 degrees:-25 degrees to -35 degrees). Since the twins have identical genotypes these differences must have arisen from other sources.

A glutamine-rich hydrophobic patch in transcription factor Sp1 contacts the dTAFII110 component of the Drosophila TFIID complex and mediates transcriptional activation

Activation of transcription by the promoter-specific factor Sp1 requires coactivators that are tightly associated with the TATA-box-binding protein (TBP) in the TFIID complex. Recent work has shown that the two glutamine-rich activation domains of Sp1, A and B, can interact with at least one component of this complex, the TBP-associated factor dTAFII110. Here we report the mapping of a region of Sp1 with alternating glutamine and hydrophobic residues which is required for the interaction with dTAFII110 and is important for mediating transcriptional activation. Substitution of bulky hydrophobic residues within this region decreased both interaction with dTAFII110 and transcriptional activation in Drosophila cells. In contrast, mutation of glutamine residues in this region had no effect. Thus, the strength of the Sp1-TAF interaction correlates with the potency of Sp1 as a transcriptional activator, indicating that this activator-TAF interaction is an important part of the mechanism of transcriptional activation. Sequence comparison of three activation domains shown to bind dTAFII110 suggests that different activators that utilize dTAFII110 as a coactivator may share common sequence features that we have determined to be important for the Sp1-dTAFII110 interaction.

Transgenic tobacco plants expressing the geminivirus BL1 protein exhibit symptoms of viral disease

Bipartite geminiviruses, such as squash leaf curl virus (SqLCV), encode two movement proteins (MPs), BR1 and BL1, that are essential for viral movement in and subsequent infection of the host plant. To elucidate the biochemical functions of these MPs and define their respective contributions to viral infection, we have generated transgenic Nicotiana benthamiana plants expressing SqLCV BR1 and BL1. Transgenic plants expressing BR1 or a truncated BL1 were phenotypically indistinguishable from wild-type N. benthamiana. In contrast, transgenic plants expressing full-length BL1, alone or in combination with BR1, were strikingly abnormal both in their growth properties and phenotypic appearance, with leaves that were mosaic and curled under, thus mimicking typical SqLCV disease symptoms in this host. BL1 was localized to the cell wall and plasma membrane fractions, whereas BR1 was predominantly in the microsomal membrane fraction. These findings demonstrate that expression of BL1 in transgenic plants is sufficient to produce viral disease symptoms, and they further suggest that BL1 and BR1 carry out distinct and independent functions in viral movement.

Incremental light detection thresholds across the central visual field of human albinos

PURPOSE

The authors investigated central retinal function in albinism by measuring incremental light detection thresholds in a group of oculocutaneous human albinos.

METHODS

Eleven oculocutaneous human albinos (six tyrosinase negative and five oculocutaneous positive), six patients with idiopathic congenital nystagmus, and six normal control subjects participated in the study. Using a Goldmann bowl perimeter, incremental light detection thresholds were measured in the vertical meridian across the central +/- 30 degrees of the retina. Target presentation times were 1 sec for all subjects, and in the case of four albinos and one patient with idiopathic nystagmus, they were limited to the low-velocity period of each nystagmus cycle.

RESULTS

For the normal control subjects, the maximum sensitivity was found to be -0.60 +/- 0.10 log units. By comparison, at 0 degrees, a range of sensitivities was obtained from the albino subjects (-0.9 to -2.1 log units) and from those with idiopathic nystagmus (-0.7 to -1.9 log units). The albinos had diverse retinal sensitivity profiles ranging from a near-normal peaked curve to a flat homogeneous profile. A variety of sensitivity profiles was also detected in those with idiopathic nystagmus, although, compared with the albino curves, a greater proportion were peaked. No sensitivity differences were found between the short and the longer target presentations.

CONCLUSIONS

The variety of retinal sensitivity profiles obtained in this study suggests that, in albinism, considerable intersubject variability in the degree of foveal hypoplasia exists and that albino "foveal" function can reach near-normal levels, for at least some visual tasks.

Different activation domains of Sp1 govern formation of multimers and mediate transcriptional synergism

The process of transcriptional activation in eukaryotes by site-specific DNA-binding proteins is a key step in gene regulation. Here we have examined the properties of four distinct activator domains of the human transcription factor Sp1. In vivo transient cotransfection assays with Sp1 show that templates bearing multiple Sp1 sites activate transcription with a high degree of synergism. However, there is no evidence of cooperative binding of Sp1 to adjacent sites. Using deletion mutants of Sp1 we have determined that the glutamine-rich activation domains A and B and the previously uncharacterized carboxy-terminal domain D are all required for Sp1 to activate transcription synergistically. Gel-shift, DNase footprinting, and chemical cross-linking experiments reveal a strong correlation between the ability of Sp1 mutants to form homomultimeric complexes and their ability to activate transcription synergistically when bound to multiple sites. We have also examined the process of superactivation, in which a molecule of Sp1 tethered to DNA via its zinc fingers can be transcriptionally enhanced by interacting directly with fingerless Sp1 molecules. The domains involved in superactivation appear to be a subset of those necessary to achieve synergistic activation. These findings suggest that different domains of Sp1 carry out distinct functions and that the formation of multimeric complexes may direct synergism and superactivation.

Visual resolution limits in human albinism

The effects of the involuntary ocular oscillations on visual resolution was examined in 22 albinos and 11 idiopaths with congenital nystagmus. The idiopaths showed a linear relationship between the proportion of the slow phase spent at low velocities (less than or equal to deg/sec) and the log of the minimum angle of resolution; such that long dwell times were compatible with good resolution. For the albinos there appeared to be a critical duration of low retinal slip velocities above which there was no improvement in acuity. This supports the contention that factors other than the congenital nystagmus limit visual resolution in the albino.

The effects of simultaneous central and peripheral field motion on the optokinetic response

The effects of central and peripheral retinal stimulation on the optokinetic response were examined using full-field, central field only, peripheral field only and simultaneous central and peripheral field motion. Stimulation of the central field in isolation produced similar responses to those obtained for full-field motion whereas peripheral field stimulation resulted in greatly reduced responses. Central field dominance was also evident during central and peripheral field motion in opposing directions. However with unidirectional, simultaneous central and peripheral stimulation the optokinetic response was determined not by the central stimulus but by whichever stimulus moved the slower.

Retinal image quality in albinos. A review

This paper describes two of the factors which affect retinal image quality in oculocutaneous albinos. Contrast detection thresholds were determined to quantify the effects of intra-ocular light scatter and the consequences of continuous retinal image motion. The implications of these results on the limits of visual performance are discussed in the light of the accompanying foveal hypoplasia.

Retinal fixation behavior in human albinos

The retinal fixation behavior of 17 albinos was examined whilst they fixated a stationary target. An optical system was arranged so that the motion of the target on the retina, due to the nystagmus, could be video-recorded. Eye movements were monitored simultaneously. Eight of the 17 subjects were judged to use consistently a retinal location compatible with the anatomical position of the fovea. The implications of this for subjects with foveal hypoplasia are discussed.

The recognition and management of albinism

Albinism is not a single entity but represents a heterogenous group of inherited disorders of pigmentation. Despite a wide variety of manifestations, all forms of albinism are characterized by several ocular features, including: nystagmus, photophobia, reduced visual acuity and a lack of stereopsis. It is the intention of this review to describe and discuss the clinical implications of albinism with particular emphasis placed on these ocular features and their effects on visual performance. Various techniques that may be employed to aid the albino will also be described.