Recently, the Marine Molecular Ecology and Chemical Ecology Team at Guangzhou Marine Laboratory published a research article entitled “Spectinabilin mitigates Aβ-associated proteotoxic stress and preserves synaptic protein expression in cellular and Caenorhabditis elegans models” in Pharmacological Research, a CAS Q1 TOP journal. Prof. Pei-Yuan Qian and Prof. Aifang Cheng of the University of Macau are the co-corresponding authors, and Xin Huang, a doctoral student in the team, is the first author. The study systematically evaluated the ability of spectinabilin, a natural product isolated from the marine-derived bacterium Streptomyces spectabilis, to alleviate Aβ-associated proteotoxicity and neuronal injury and investigated its potential mechanisms of action.
Alzheimer’s disease is a progressive neurodegenerative disorder characterized by cognitive decline. Its development involves several interconnected pathological processes, including abnormal amyloid-β assembly, oxidative stress, mitochondrial dysfunction, and synaptic injury. Soluble Aβ assemblies are particularly associated with early neuronal and synaptic dysfunction. Identifying small molecules that can modify Aβ assembly while maintaining neuronal homeostasis therefore represents an important direction in Alzheimer’s disease research. Marine microorganisms possess distinctive metabolic capabilities and produce structurally diverse natural products, making them a valuable source of novel neuroprotective molecules.
The study found that spectinabilin directly associated with Aβ42 and altered its subsequent assembly, reducing the formation of β-sheet-rich aggregates and elongated fibrils. In neuronal cell models, spectinabilin attenuated glutamate- and Aβ-associated cellular injury and preserved mitochondrial membrane potential during Aβ exposure. In Aβ-expressing C. elegans models, the compound reduced Aβ-associated deposits and oxidative stress, delayed paralysis, extended lifespan, and improved chemotaxis. These findings indicate that spectinabilin can alleviate Aβ-associated proteotoxicity and improve selected functional outcomes across different experimental models.
Transcriptomic and molecular analyses further showed that spectinabilin partially opposed the abnormal gene-expression changes associated with the Aβ model, particularly those involving synaptic signaling, G protein-coupled receptor-associated signaling, and the regulation of membrane potential. Spectinabilin also promoted the expression of synaptic and cAMP-related genes, restored the levels of the presynaptic proteins Rab3A and VAMP2, and shifted Aβ-associated CREB phosphorylation abnormalities toward the control state. Pharmacological inhibition experiments further suggested that PKA-associated signaling contributes to the spectinabilin-mediated recovery of CREB regulation and presynaptic protein expression.
By integrating biochemical, cellular, transcriptomic, pharmacological, and organismal evidence, the study reveals the potential of spectinabilin to modify Aβ assembly, maintain mitochondrial homeostasis, and preserve synaptic function. The findings provide new experimental insight into the relationship among Aβ proteotoxicity, mitochondrial dysfunction, and synaptic impairment, while highlighting marine microbial natural products as a promising source of neuroprotective small-molecule scaffolds. The current study remains at the in vitro, cellular, and C. elegans model stage. Further studies are required to evaluate the brain exposure, pharmacokinetics, safety, and efficacy of spectinabilin in mammalian models.
This work was supported by the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), the Government of the Hong Kong Special Administrative Region, the Otto Poon Center for Climate Resilience and Sustainability at The Hong Kong University of Science and Technology, the Macao Science and Technology Development Fund, and the University of Macau.
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