Targeting TRPV1-mediated autophagy attenuates nitrogen mustard-induced dermal toxicity

Signal Transduct Target Ther. 2021 Jan 25;6(1):29. doi: 10.1038/s41392-020-00389-z.

Abstract

Nitrogen mustard (NM) causes severe vesicating skin injury, which lacks effective targeted therapies. The major limitation is that the specific mechanism of NM-induced skin injury is not well understood. Recently, autophagy has been found to play important roles in physical and chemical exposure-caused cutaneous injuries. However, whether autophagy contributes to NM-induced dermal toxicity is unclear. Herein, we initially confirmed that NM dose-dependently caused cell death and induced autophagy in keratinocytes. Suppression of autophagy by 3-methyladenine, chloroquine, and bafilomycin A1 or ATG5 siRNA attenuated NM-induced keratinocyte cell death. Furthermore, NM increased transient receptor potential vanilloid 1 (TRPV1) expression, intracellular Ca2+ content, and the activities of Ca2+/calmodulin-dependent kinase kinase β (CaMKKβ), AMP-activated protein kinase (AMPK), unc-51-like kinase 1 (ULK1), and mammalian target of rapamycin (mTOR). NM-induced autophagy in keratinocytes was abolished by treatment with inhibitors of TRPV1 (capsazepine), CaMKKβ (STO-609), AMPK (compound C), and ULK1 (SBI-0206965) as well as TRPV1, CaMKKβ, and AMPK siRNA transfection. In addition, an mTOR inhibitor (rapamycin) had no significant effect on NM-stimulated autophagy or cell death of keratinocytes. Finally, the results of the in vivo experiment in NM-treated skin tissues were consistent with the findings of the in vitro experiment. In conclusion, NM-caused dermal toxicity by overactivating autophagy partially through the activation of TRPV1-Ca2+-CaMKKβ-AMPK-ULK1 signaling pathway. These results suggest that blocking TRPV1-dependent autophagy could be a potential treatment strategy for NM-caused cutaneous injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinase Kinases / genetics
  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Animals
  • Autophagy / genetics*
  • Autophagy-Related Protein 5 / genetics*
  • Autophagy-Related Protein-1 Homolog / genetics
  • Blister / genetics
  • Blister / pathology
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase / genetics
  • Cell Death / drug effects
  • Chloroquine / pharmacology
  • Humans
  • Keratinocytes / drug effects
  • Keratinocytes / pathology
  • Macrolides / pharmacology
  • Mechlorethamine / toxicity
  • Mice
  • RNA, Small Interfering / genetics
  • Sirolimus / pharmacology
  • Skin / drug effects
  • Skin / injuries
  • Skin / pathology
  • Skin Diseases / chemically induced
  • Skin Diseases / drug therapy
  • Skin Diseases / genetics*
  • Skin Diseases / pathology
  • TOR Serine-Threonine Kinases / genetics
  • TRPV Cation Channels / genetics*

Substances

  • ATG5 protein, human
  • Autophagy-Related Protein 5
  • Macrolides
  • RNA, Small Interfering
  • TRPV Cation Channels
  • TRPV1 protein, human
  • Mechlorethamine
  • 3-methyladenine
  • Chloroquine
  • bafilomycin A1
  • Autophagy-Related Protein-1 Homolog
  • TOR Serine-Threonine Kinases
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase
  • AMP-Activated Protein Kinase Kinases
  • Adenine
  • Sirolimus