Nos1, also known as neuronal nitric oxide synthase (nNOS), is an enzyme that uses L-arginine as a substrate to produce nitric oxide (NO) as a by-product. NO is involved in multiple biological pathways and is highly enriched in the brain, where it mediates functions such as learning, memory development, synaptic plasticity, and neuronal development. It also has implications in diseases like Alzheimer's disease, psychiatric disorders, and behavioral deficits [1].

In a Nos1-deficient mouse model, lack of Nos1 activity led to GnRH deficiency associated with sensory and intellectual comorbidities, including sexual maturation defects, anosmia, hearing loss, and intellectual disability in both humans and mice. However, inhaled NO treatment during minipuberty reversed deficits in sexual maturation, olfaction, and cognition in Nos1-mutant mice, suggesting a potential therapy for NO-deficient humans [2]. In melanoma cells, NOS1-knockout suppressed cell proliferation, blocked cell cycling, decreased tumor growth, and increased immune cell infiltration. Inhibition of NOS1 also enhanced the interferon response of melanoma cells, indicating its role in tumor growth promotion and immune escape [3].

In conclusion, Nos1 plays crucial roles in multiple biological processes, especially in the brain. Gene-knockout mouse models have revealed its significance in diseases such as hypogonadotropic hypogonadism with associated sensory and cognitive deficits and melanoma. Understanding the functions of Nos1 through these models provides insights into disease mechanisms and potential therapeutic strategies for related conditions.

References:

1. Solanki, Kundan, Rajpoot, Sajjan, Bezsonov, Evgeny E, Wary, Kishore, Baig, Mirza S. 2022. The expanding roles of neuronal nitric oxide synthase (NOS1). In PeerJ, 10, e13651. doi:10.7717/peerj.13651. https://pubmed.ncbi.nlm.nih.gov/35821897/

2. Chachlaki, Konstantina, Messina, Andrea, Delli, Virginia, Pitteloud, Nelly, Prevot, Vincent. 2022. NOS1 mutations cause hypogonadotropic hypogonadism with sensory and cognitive deficits that can be reversed in infantile mice. In Science translational medicine, 14, eabh2369. doi:10.1126/scitranslmed.abh2369. https://pubmed.ncbi.nlm.nih.gov/36197968/

3. Chen, Xi, Zou, Zhiwei, Wang, Qianli, Hao, Bingtao, Liu, Qiuzhen. 2022. Inhibition of NOS1 promotes the interferon response of melanoma cells. In Journal of translational medicine, 20, 205. doi:10.1186/s12967-022-03403-w. https://pubmed.ncbi.nlm.nih.gov/35538490/