D'Ursi, A. M. | Search bioRxiv

bioRxiv2025

Analyzing nicotine action against amyloid toxicity by NMR-pharmacometabolomics: an exploratory study.

Alzheimers disease (AD) is the primary neurodegenerative disease spread worldwide. One of the main histopathological hallmarks of AD is amyloid plaque deposition in the brain. Despite some epidemiological studies demonstrating that cigarette smoke is a factor in predisposing people to AD, nicotine, the principal alkaloid of Nicotiana Tobacco, has been widely studied for its ability to improve cognitive performance, both in animal models and in human studies. Several hypotheses have been proposed to explain the mechanism of action underlying the beneficial effect of Nicotine in AD; however, this is still questioned. To have new insights into the molecular mechanism underlying the neuroprotective action of Nicotine in Alzheimers disease, we performed an NMR metabolomic analysis of SH-SY5Y neuroblastoma cells treated with A{beta} (1-42) in the presence of nicotine. Our data show that the neuroprotective action of nicotine resides in its ability to restore the systemic unbalanced metabolism associated with AD. In particular, nicotine reverses most A{beta} (1-42)-induced metabolic impairments, including those related to amino acid metabolism, especially those involved in neurotransmission, as well as alterations in energy metabolism and membrane phospholipid metabolism.

cell biology↗

bioRxiv2025

RNase H1 counteracts DNA damage and ameliorates SMN-dependent phenotypes in a Drosophila model of Spinal Muscular Atrophy

Spinal Muscular Atrophy (SMA) is caused by a deficiency of the Survival Motor Neuron (SMN) protein. Mutations in SMN disrupt mRNA splicing and translation, leading to maladaptive changes in transcriptomes, proteomes, neuroinflammation, and metabolism, which drive motor neuron degeneration in SMA patients. Using a Drosophila SMA model, we found that systemic depletion of Smn leads to accumulation of RNA:DNA hybrids (R-loops), increased DNA damage, dysregulation of amino acids and sugar metabolism and activation of the innate immune response, recapitulating key pathological features reported in mammalian models and severe SMA patients. Persistent DNA damage in Smn-deficient flies alters cell proliferation rates in larval brains and induces extensive cell death in the developing eye. Importantly here, we show that stimulating the resolution of RNA:DNA hybrids with transgenic human RNAse H1 prevents the accumulation of DNA damage and attenuates the transcriptome and amino acid alterations induced by Smn depletion, mitigating the Smn-dependent cellular and developmental abnormalities, in Smn-deficient flies. Our data suggest that depletion of Smn causes an accumulation of aberrant transcripts and chronic DNA damage, which--along with the altered metabolomic profiles associated with Smn deficiency--trigger systemic inflammatory responses, ultimately affecting neuronal function and survival.

genetics↗