2. Academic Validation
  3. Cadmium induces endosomal/lysosomal enlargement and blocks autophagy flux in rat hepatocytes by damaging microtubules

Cadmium induces endosomal/lysosomal enlargement and blocks autophagy flux in rat hepatocytes by damaging microtubules

  • Ecotoxicol Environ Saf. 2021 Nov 19:228:112993. doi: 10.1016/j.ecoenv.2021.112993.
Junzhao Yuan 1,  Yumeng Zhao 2,  Yuni Bai 2,  Jianhong Gu 2,  Yan Yuan 2,  Xuezhong Liu 2,  Zongping Liu 1,  Hui Zou 3,  Jianchun Bian 4
Affiliations

Affiliations

  • 1 College of Veterinary Medicine, Yangzhou University, 12 Wenhui East Road, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, Jiangsu, China.
  • 2 College of Veterinary Medicine, Yangzhou University, 12 Wenhui East Road, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China.
  • 3 College of Veterinary Medicine, Yangzhou University, 12 Wenhui East Road, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, Jiangsu, China. Electronic address: [email protected].
  • 4 College of Veterinary Medicine, Yangzhou University, 12 Wenhui East Road, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, Jiangsu, China. Electronic address: [email protected].
PMID: 34808507 DOI: 10.1016/j.ecoenv.2021.112993
Abstract

Acute exposure to cadmium (Cd) causes vacuolar degeneration in buffalo rat liver 3 A (BRL 3 A) cells. The present study aimed to determine the relationship between Cd-induced microtubule damage and intracellular vacuolar degeneration. Western blotting results showed that Cd damaged the microtubule network and downregulated the expression of microtubule-associated proteins-kinesin-1 heavy chain (KIF5B), γ-tubulin, and acetylated α-tubulin in BRL 3 A cells. Immunofluorescence staining revealed that Cd inhibited interactions between α-tubulin and microtubule-associated protein 4 (MAP4) as well as KIF5B. Increasing Cd concentrations decreased the levels of the lipid kinase, PIKfyve, which regulates the activity of endosome-lysosome fission. Immunofluorescence and transmission electron microscopy revealed vacuole-like organelles that were late endosomes and lysosomes. The PIKfyve Inhibitor, YM201636, and the microtubule depolymerizer, nocodazole, aggravated Cd-induced endosome-lysosome enlargement. Knocking down the kif5b gene that encodes KIF5B intensified the enlargement of endosome-lysosomes and expression of early endosome antigen 1 (EEA1), Ras-related protein Rab-7a (RAB7), and lysosome-associated membrane glycoprotein 2 (LAMP2). Nocodazole, YM201636, and the knockdown of kif5b blocked autophagic flux. We concluded that Cd-induced damage to the microtubule network is the main reason for endosome-lysosome enlargement and autophagic flux blockage in BRL 3 A cells, and kinesin-1 plays a critical role in this process.

Keywords

Autophagic flux; Cadmium; Endosome; Kinesin-1; Lysosome; Microtubule.

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