Neu1, also known as Neuraminidase 1, is a lysosomal sialidase that cleaves terminal α-linked sialic acid residues from sialylglycans [2]. It is ubiquitously expressed across various tissues and is crucial for lysosomal catabolic functions. Neu1 is involved in multiple pathways such as immune response modulation, elastic fiber assembly modulation, insulin signaling, and cell proliferation [1].

In a GS model mouse with homozygotic Ctsa IVS6 + 1 g/a mutation causing simultaneous deficiency of Ctsa and Neu1, symptoms like myoclonic seizures, suppressed behavior, and sialylglycan accumulation associated with neurovisceral inflammation were observed, indicating Neu1's role in preventing such pathological manifestations [2]. In Neu1-knockout zebrafish, abnormal emotional behavior was detected, along with changes in anxiety-related genes and lysosomal exocytosis-related genes, suggesting Neu1's role in normal emotional behavior [4]. In male mice, tubular epithelial cell-specific NEU1 knockout inhibited epithelial-to-mesenchymal transition, inflammatory cytokines production, and collagen deposition in renal fibrosis models, showing NEU1's promoting role in renal fibrosis [3].

In conclusion, Neu1 is essential for normal physiological functions, with its deficiency leading to various pathological conditions. Gene-knockout models in mice and zebrafish have been valuable in revealing its role in diseases such as sialidosis, neurodegeneration-related abnormal behaviors, and renal fibrosis, providing insights into potential therapeutic strategies targeting Neu1 for these diseases.