Novel mutation of COG5 in a Taiwanese girl with congenital disorders of glycosylation manifesting as developmental delay.

We are documenting the case of An 11-year-old girl who has been followed up at our out-patient clinic since birth with clinical presentations including intrauterine growth restriction, recurrent periodic fever in infancy, hypotonia, global developmental delay, liver function impairment with cirrhotic changes, and clinodactyly. Congenital abnormalities were suspected but a series of examinations including brain MRI, liver biopsy and muscle biopsy yielded insignificant findings. Whole genome sequencing (WGS) was conducted and revealed three novel mutations (c2T > G, c1826T > C, c.556-560delAGTAAinsCT) of the COG5 gene. A diagnosis of COG5-congenital disorders of glycosylation (COG5-CDG, or CDG IIi), with neurologic presentation was established. Sanger sequencing in the patient and her parents confirmed the compound heterozygous mutation. Upon literature review, we identified the patient as the first case of COG5-CDG in Taiwan. Our study enhances the clarity of the correlation between the mutative genes and the presentation of COG5-CDG.

Unveiling novel LRP5 pathogenic variant in familial exudative vitreoretinopathy: Diverse phenotypic expressions in a mother-daughter duo.

PURPOSE: This report aims to delineate distinct phenotypes of Familial Exudative Vitreoretinopathy (FEVR) observed in a mother and her daughter, both harboring a novel LRP5 pathogenic variation. METHODS: The investigation involves a retrospective review of medical records accompanied by multimodal imaging. Molecular characterization was performed using whole exon sequencing, and the pathogenic variant was subsequently confirmed through Sanger sequencing. RESULT: A 6-year-old girl diagnosed with anisometropic amblyopia exhibited macular dragging and peripheral avascular retina in her right eye. Whole exon sequencing identified a previously unreported heterozygous missense LRP5 pathogenic variation, Glu528Lys. Simultaneously, her 43-year-old mother also carried the same mutation, manifesting peripheral exudations, avascular areas, and multiple microaneurysms. Notably, both cases presented distinctive phenotypes of FEVR. CONCLUSION: Our findings underscore the diversity in clinical presentations associated with FEVR, emphasizing the pivotal role of genetic evaluation. Despite variations in severity between the eyes of the same patient, it is crucial to remain vigilant for potential progression to a pathological status in the seemingly normal eye. Additionally, this study contributes to expanding the genetic spectrum of FEVR.

Sublethal Imidacloprid Administration to Honey Bee Workers is More Lethal to the Queen Larvae.

Imidacloprid and other neonicotinoid insecticides severely impact the performance and survival of honey bees and other pollinators. In the present study, we focused on the gene expression profile of newly emerged Apis mellifera queen bees after sublethal imidacloprid treatment during the larval stage. Royal jelly containing 1 ppb imidacloprid was provided to larvae for 3 consecutive days (2-4 days postemergence). Queen larvae treated with imidacloprid showed lower capping and emergence rates (35.5% and 24.22%, respectively) than did control larvae (61.68% and 52.95%, respectively), indicating a high failure rate of queen rearing associated with imidacloprid exposure during the larval stage. The molecular response to imidacloprid treatment was examined next. By comparing the gene expression profiles of imidacloprid-treated queen larvae and those of control queen larvae using DESeq2, we identified 215 differentially expressed genes, with 105 and 111 up- and downregulated genes, respectively. Gene Ontology results indicated that chitin binding- and calcium ion binding-related genes were upregulated, while phototransduction- and visual perception-related genes were downregulated. The high mortality rate and altered gene expression profiles suggest that treatment with even 1 ppb imidacloprid can severely impact queen bee survival. Environ Toxicol Chem 2024;00:1-11. © 2024 SETAC.

Amyloid Modifier SERF1a Accelerates Alzheimer's Amyloid-ß Fibrillization and Exacerbates the Cytotoxicity.

Alzheimer's disease (AD) is a devastating, progressive neurodegenerative disease affecting the elderly in the world. The pathological hallmark senile plaques are mainly composed of amyloid-ß (Aß), in which the main isoforms are Aß40 and Aß42. Aß is prone to aggregate and ultimately forms amyloid fibrils in the brains of AD patients. Factors that alter the Aß aggregation process have been considered to be potential targets for treatments of AD. Modifier of aggregation 4 (MOAG-4)/small EDRK-rich factor (SERF) was previously selected from a chemical mutagenesis screen and identified as an amyloid modifier that promotes amyloid aggregation for α-synuclein, huntingtin, and Aß40. The interaction and effect of yeast ScSERF on Aß40 were previously described. Here, we examined the human SERF1a effect on Aß40 and Aß42 fibrillization by the Thioflavin T assay and found that SERF1a accelerated Aß fibrillization in a dose-dependent manner without changing the fibril amount and without incorporation. By Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), we found that SERF1a altered the secondary structures and the morphology of Aß fibrils. The electrospray ionization mass spectrometry (ESI-MS) and analytical ultracentrifugation (AUC) results showed that SERF1a binds to Aß in a 1:1 stoichiometry. Moreover, the NMR study showed that SERF1a interacts with Aß via its N-terminal region. Cytotoxicity assay demonstrated that SERF1a enhanced toxicity of Aß intermediates, and the effect can be rescued by SERF1a antibody. Overall, our study provides the underlying molecular mechanism for the SERF1a effect on Aß fibrillization and facilitates the therapeutic development of AD.

Detection of Femtomolar Amyloid-ß Peptides for Early-Stage Identification of Alzheimer's Amyloid-ß Aggregation with Functionalized Gold Nanoparticles.

Progressive amyloid-ß (Aß) fibrillar aggregates have long been considered as the pathogenesis of Alzheimer's disease (AD). Biocompatible and stable cysteine-Aß peptide-conjugated gold nanoparticles (Cys-Aß@AuNP) are demonstrated as suitable materials for detecting subfemtomolar Aß peptides in human plasma. Incubation with Aß peptides causes the Cys-Aß@AuNP to aggregate and changes its absorption spectra. The spectral change is especially apparent and noticeable when detecting subfemtomolar Aß peptides, and the aggregates contain only two or three AuNPs. Cys-Aß@AuNP can also be used to identify early-stage Aß oligomerization, which is not possible using the conventional method, in which the fluorescence of thioflavin-T is measured. The ability to detect Aß oligomerization can facilitate therapeutics for AD. In addition, the binding of Aß peptides by Cys-Aß@AuNP in combination with centrifugation redirects the conventional Aß aggregation pathway and can effectively inhibit the formation of toxic Aß oligomers or fibrils. Therefore, the proposed Cys-Aß@AuNP can also be used to develop effective therapeutic agents to inhibit Aß aggregation. The results obtained in this study are expected to open revolutionary ways to both detect and inhibit Aß aggregation at an early stage.

Optimization of sequence and chiral content enhances therapeutic potential of tilapia piscidin peptides.

Because antimicrobial peptides (AMPs) often exhibit broad-spectrum bactericidal potency, we sought to develop peptide-based antimicrobials for potential clinical use against drug-resistant pathogens. To accomplish this goal, we first optimized the amino acid sequence of a broad-spectrum AMP known as Tilapia Piscidin 4 (TP4). Then, we used the optimized sequence to create a pair of heterochiral variants (TP4-α and TP4-ß) with different percentages of D-enantiomers, as poly-L peptides often exhibit poor pharmacokinetic profiles. The conformations of the peptide pair exhibited inverted chirality according to CD and NMR spectroscopic analyses. Both heterochiral peptides displayed enhanced stability and low hemolysis activities. Irrespective of their different d-enantiomer contents, both heterochiral peptides exhibited bactericidal activities in the presence of human serum or physiological enzymes. However, the peptide with higher d-amino acid content (TP4-ß) caused better bacterial clearance when tested in mice infected with NDM-1 K. pneumoniae. In addition, we observed a relatively higher hydrogen bonding affinity in a simulation of the interaction between TP4-ß and a model bacterial membrane. In sum, our results demonstrate that the current design strategy may be applicable for development of new molecules with enhanced stability and in vivo antimicrobial activity.

Binding structures of SERF1a with NT17-polyQ peptides of huntingtin exon 1 revealed by SEC-SWAXS, NMR and molecular simulation.

The aberrant fibrillization of huntingtin exon 1 (Httex1) characterized by an expanded polyglutamine (polyQ) tract is a defining feature of Huntington's disease, a neurodegenerative disorder. Recent investigations underscore the involvement of a small EDRK-rich factor 1a (SERF1a) in promoting Httex1 fibrillization through interactions with its N terminus. By establishing an integrated approach with size-exclusion-column-based small- and wide-angle X-ray scattering (SEC-SWAXS), NMR, and molecular simulations using Rosetta, the analysis here reveals a tight binding of two NT17 fragments of Httex1 (comprising the initial 17 amino acids at the N terminus) to the N-terminal region of SERF1a. In contrast, examination of the complex structure of SERF1a with a coiled NT17-polyQ peptide (33 amino acids in total) indicates sparse contacts of the NT17 and polyQ segments with the N-terminal side of SERF1a. Furthermore, the integrated SEC-SWAXS and molecular-simulation analysis suggests that the coiled NT17 segment can transform into a helical conformation when associated with a polyQ segment exhibiting high helical content. Intriguingly, NT17-polyQ peptides with enhanced secondary structures display diminished interactions with SERF1a. This insight into the conformation-dependent binding of NT17 provides clues to a catalytic association mechanism underlying SERF1a's facilitation of Httext1 fibrillization.

Sequential rearrangement and stereochemical reorganization to design an antimicrobial peptide with enhanced stability.

Antimicrobial peptides (AMPs) are natural molecules that function within the innate immune system to counteract pathogenic invasion and minimize the detrimental consequences of infection. However, utilizing these molecules for medical applications has been challenging. In this study, we selected a model AMP with poor stability, Tilapia Piscidin 4 (TP4), and modified its sequence and chirality (TP4-γ) to improve its potential for clinical application. The strategy of chirality inversion was inspired by the cereulide peptide, which has a DDLL enantiomer pattern and exhibits exceptional stability. Sequential substitution of key residues and selective chirality inversion yielded a less toxic peptide with enhanced stability and notable antimicrobial activity. In addition to its superior stability profile and antimicrobial activity, TP4-γ treatment reduced the level of LPS-induced nitric oxide (NO) release in a macrophage cell line. This reduction in NO release may reflect anti-inflammatory properties, as NO is widely known to promote inflammatory processes. Hence, our heterochiral peptide construct shows a more suitable pharmacokinetic profile than its parental compound, and further studies are warranted to develop the molecule for potential clinical application.

Sulfated disaccharide protects membrane and DNA damages from arginine-rich dipeptide repeats in ALS.

Hexanucleotide repeat expansion in C9ORF72 (C9) is the most prevalent mutation among amyotrophic lateral sclerosis (ALS) patients. The patients carry over ~30 to hundreds or thousands of repeats translated to dipeptide repeats (DPRs) where poly-glycine-arginine (GR) and poly-proline-arginine (PR) are most toxic. The structure-function relationship is still unknown. Here, we examined the minimal neurotoxic repeat number of poly-GR and found that extension of the repeat number led to a loose helical structure disrupting plasma and nuclear membrane. Poly-GR/PR bound to nucleotides and interfered with transcription. We screened and identified a sulfated disaccharide that bound to poly-GR/PR and rescued poly-GR/PR-induced toxicity in neuroblastoma and C9-ALS-iPSC-derived motor neurons. The compound rescued the shortened life span and defective locomotion in poly-GR/PR expressing Drosophila model and improved motor behavior in poly-GR-injected mouse model. Overall, our results reveal structural and toxicity mechanisms for poly-GR/PR and facilitate therapeutic development for C9-ALS.