Biology subjects

Geng, G.

Publications and source records attributed to Geng, G..

5 recordsLinked to original sources

bioRxiv2026

Combination of engineered cell type-specific promoters and a high-efficiency AAV capsid restores hearing in adult DFNB1 mice model with demonstrated safety in nonhuman primate

A major challenge in gene therapy for GJB2-related hearing loss (DFNB1)--the most common form of hereditary deafness--is achieving efficient and precise connexin 26 delivery. Herein, we engineered two cell type-specific promoters (GJB2-1 and WFS1-2274) and developed an AAV capsid, AAV-MAS012, with enhanced transduction efficiency in mature cochlear cells. Our AAV-mediated gene therapy systems restored hearing of low-to-mid-frequencies in newborn Gjb2 cKO mice to wild-type levels and maintained for 45 weeks. Additionally, our therapeutic systems restored low-to-mid-frequencies hearing function to wild-type levels in adult Gjb2 cKO mice. A humanized version of the therapy, AAV-MAS012-WFS1-2274-hGJB2, rescued hearing function in two distinct Gjb2-deficient mouse models, and demonstrated a favorable safety profile in nonhuman primates. This study represents the first successful hearing restoration in adult Gjb2-deficient mice. The significant therapeutic efficacy of the humanized gene therapy system shows great potential for clinical translation in DFNB1 patients.

genetics↗

bioRxiv2021

Develop an efficient and specific AAV-based labeling system for Muller glia in mice

Cell degeneration in the retina leads to several ocular diseases and vision loss. Considerable research efforts focus on reprogramming Muller glia (MG) into functional cells to rescue vision as a promising therapeutic strategy, although whether MG can convert into functional bipolar cells, retinal ganglia cells (RGCs), rods or cones in mammals remains controversial. The broad applicability of tracking MG differentiation thus presents a need for improved labeling efficiency and specificity. Here, we compared AAV-based labeling strategies with conventional lineage-tracking by crossing transgenic mouse lines. We found that reporter expression was weak and not MG-specific in mGFAP-Cre transgenic mice. Different AAV serotypes showed a range of efficiency and specificity in labeling MG, leading us to optimize a human GFAP-Cre reporter system packaged in the AAV9 serotype with the WPRE (WPRE, woodchuck hepatitis virus post-transcriptional regulatory element) removed. The hGFAP-Cre- {Delta}WPRE reporter could label 20-73.8% MGs, with non-specific RGC labeling rates ranging from 0-0.08% at doses of 1 x 108 to 1010 vector genomes (vg) per eye, an approximate 40-fold reduction compared with the AAV9-hGFAP-Cre-WPRE labeling system. Furthermore, we validated the availability of the label system to trace MG reprogramming and also detected false-positive results reported previously. The AAV9-hGFAP-Cre-{Delta}WPRE system thus represents a highly efficient and specific labeling system for MG, providing a valuable tool for tracking cell fate in vivo.

neuroscience↗

bioRxiv2021

Multiple levels of triggered factors and positive effect of cell-to-cell bottleneck in mutation repair of RNA viruses

Debilitating mutation in RNA viruses can be repaired via different mechanisms, while triggering factors of mutation repair were poorly understood. In this study, multiple levels of triggering factors of mutation repair was identified based on genetic damage of tRNA-like structure (TLS) in cucumber mosaic virus (CMV). TLS mutation in different RNAs of CMV distinctively impacted the pathogenicity and mutation repair. Relative quantity defect of RNA2 or quality defect of RNA3 resulting from TLS mutation was correlated with high rate of mutation repair, and TLS mutation of RNA1 failed to be repaired. However, TLS mutation of RNA1 can be repaired in the mixed inoculation with RNA2 having pre-termination mutation of 2b or at the low dose of original inoculation, especially around dilution end-point. Taken together, TLS mutation resulting into quality or quantity defect of viral genome or TLS mutation at low dose around dilution end-point was inclined to be repaired. In addition, different levels of mutation repair of TLS necessarily required the cell-to-cell movement, which implied the positive effect of cell-to-cell bottleneck on evolution of low-fitness virus, a phenomenon opposite to the Muller ratchet. This study provided important revelations on virus evolution and application of viral mild vaccine. Author summaryDue to the low-fidelity of replicase, debilitating RNA viruses can be repaired through different mechanisms, which implied the resilience of RNA viruses. In this study, we identified multiple levels of triggered factors and occurrence occasion of mutation repair using the divided genome of CMV, which contained conserved cis-element tRNA-like structure (TLS) at the 3end. TLS mutation of different RNA in CMV presented different rate of mutation repair from 0-80%. TLS mutation resulting into genomic quality or quantity defect or at low dose around dilution end-point was inclined to be repaired. However, all above types of mutation repair necessarily required cell-to-cell movement, which presented the positive effect of cell-to-cell bottleneck on virus evolution and increased fitness of low-fitness RNA viruses. It is an opposite phenomenon to the Muller ratchet, in which bottleneck always decreased the fitness of viruses. Except to identify the triggering factors of mutation repair in RNA viruses, this study also provided important revelations on creation and application of mild vaccine based on RNA viruses.

pathology↗

bioRxiv2021

A novel type of IRES having variable numbers of eIF4E-binding site and synergistic effect in RNA2 of WYMV isolates

Some viral proteins were translated in cap-independent manner via internal ribosome entry site (IRES), which ever maintained conservative characteristic among different isolates of same species of virus. However, IRES activity presented 7-fold of variance in RNA2 of wheat yellow mosaic virus (WYMV) HC and LYJN isolates. Based on RNA structure probing and mutagenesis assay, the loosened middle stem of H1 and hepta-nucleotide top loop of H2 in LYJN isolate synergistically ensured the higher IRES activity than that in HC isolate. In addition, the conserved top loop of H1 ensured basic IRES activity in HC and LYJN isolates. RNA2 5'-UTR specifically interacted with the wheat eIF4E, which was accomplished by the top loop of H1 in HC isolate or the top loop of H1 and H2 in LYJN isolate. Different IRES activity of WYMV RNA2 was regulated by different numbers of eIF4E-binding site and their synergistic effect, which was accomplished by the proximity of H1 and H2 due to the flexibility of middle stem in H1. It is represented a novel evolution pattern of IRES.

microbiology↗

bioRxiv2018

Loss of SDHB reprograms energy metabolisms and inhibits high fat diet induced metabolic syndromes

Mitochondrial respiratory complex II utilizes succinate, key substrate of the Krebs cycle, for oxidative phosphorylation, which is essential for glucose metabolism. Mutations of complex II cause cancers and mitochondrial diseases, raising a critical question of the (patho-)physiological functions. To address the fundamental role of complex II in systemic energy metabolism, we specifically knockout SDHB in mice liver, a key complex II subunit that tethers the catalytic SDHA subunit and transfers the electrons to ubiquinone, and found that SHDB deficiency abolishes the assembly of complex II without affecting other respiration complexes while largely retaining SDHA stability. SHDB ablation reprograms energy metabolism and hyperactivates the glycolysis, Krebs cycle and {beta}-oxidation pathways, leading to catastrophic energy deficit and early death. Strikingly, sucrose supplementation or high fat diet resumes both glucose and lipid metabolism and prevent early death. Also, SDHB deficient mice are completely resistant to high fat diet induced obesity. Our findings reveal that the unanticipated role of complex II orchestrating both lipid and glucose metabolisms, and suggest that SDHB is an ideal therapeutic target for combating obesity.

molecular biology↗