Niclosamide Triggers Non-Canonical LC3 Lipidation

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Autophagy is a crucial cellular process for degrading damaged components, activated by stress.
• Non-canonical autophagy (NCA) represents an alternative pathway, distinct from the canonical ATG protein-dependent mechanism.
• Non-canonical LC3 lipidation (NCLL) is increasingly recognized as a marker for NCA.

Purpose of the Study:

• To investigate the non-canonical autophagy-inducing effects of niclosamide (Nic).
• To elucidate the molecular mechanisms underlying Nic-induced non-canonical LC3 lipidation (NCLL).

Main Methods:

• Utilized cell-based assays to study autophagy induction by niclosamide.
• Investigated the involvement of specific protein complexes (ULK1, Beclin 1) and ubiquitin systems.
• Assessed the role of V-ATPase, Golgi complex, and vimentin in Nic-induced NCLL.

Main Results:

• Niclosamide was found to induce non-canonical LC3 lipidation (NCLL).
• Nic-induced NCLL was independent of the ULK1 and Beclin 1 complexes but dependent on ubiquitin-like conjugation systems.
• While V-ATPase inhibitors affected NCLL, the process itself was V-ATPase independent. The Golgi complex and vimentin were implicated.

Conclusions:

• Niclosamide triggers a unique form of non-canonical autophagy (NCA) characterized by non-canonical LC3 lipidation (NCLL).
• The findings highlight the involvement of ubiquitin systems, Golgi complex, and vimentin in this process.
• This study expands the understanding of niclosamide's mechanisms and its potential pharmacological applications.