Guangcong Peng

Abstract Single‐nucleotide variants (SNVs) represent a significant form of genetic variation linked to various diseases. CRISPR‐mediated base editing has emerged as a powerful method for modeling diseases caused by SNVs, particularly in zebrafish, which serve as an excellent platform for investigating disease mechanisms and conducting drug screenings. However, existing cytosine base editors (CBEs) for zebrafish often have broad editing windows and strong sequence preferences, limiting their effectiveness. In this study, zebrafish (z) TadA‐derived cytosine base editors, termed zTadA‐CBEs, are developed by introducing key mutations into the TadA8e enzyme. These novel editors demonstrate improved efficiency and precision in cytosine base editing. Specifically, zTadA‐BE4max and zTadA‐BEmv offer complementary editing windows, while zTadA‐SpRY‐BE4max allows for PAM‐flexible editing. Using zTadA‐CBEs, a precise disease model for Axenfeld‐Rieger syndrome is established, and created two new models for Hermansky‐Pudlak syndrome. Additionally, a novel albinism model carrying two pathogenic SNVs in the F0 generation is developed. By employing specifically designed sgRNA, the fms ts± missense mutation is corrected back to the wild‐type nucleotide (C > T), successfully restoring macrophage levels to normal. These findings underscore the potential of zTadA‐CBEs to enhance genome editing techniques and their applications in developing therapies for SNV‐related disorders.

Introduction: Emerging evidence suggests that exercise-induced fatigue negatively affects nervous system function, yet effective mitigation strategies are limited. This study aimed to determine whether intranasal methylene blue (MB) could prevent neurological deficits induced by exhaustive exercise in a rat model. Methods: We utilized a rat exhaustive exercise training paradigm. Animal body weight was monitored, and a battery of behavioral tests was conducted to evaluate locomotor activity, anxiety-like behaviors, and spatial learning and memory. At the cellular level, we assessed neuron loss, apoptosis, synaptic proteins, myelin sheath, gliosis, and mitochondrial morphology in the hippocampal CA1 region and the striatum. Results: Rats subjected to exhaustive exercise exhibited reduced locomotor activity, increased anxiety-like behaviors, and impaired spatial memory. This was associated with significant neuron loss, activation of apoptotic pathways, loss of synaptic proteins and myelin sheath, gliosis, and compromised mitochondrial morphology in the hippocampus and striatum. Notably, intranasal MB treatment significantly rescued these neuronal damages and improved performance in behavioral tests. Discussion: Our findings demonstrate the neuroprotective effects of intranasal MB against exhaustive exercise-induced neurological deficits. This suggests that MB is a promising therapeutic agent for preventing the adverse neurological consequences of extreme physical exertion.