CCR5 Activation Promotes NLRP1-Dependent Neuronal Pyroptosis via CCR5/PKA/CREB Pathway After Intracerebral Hemorrhage

Stroke. 2021 Dec;52(12):4021-4032. doi: 10.1161/STROKEAHA.120.033285. Epub 2021 Nov 1.

Abstract

Background and purpose: Neuronal pyroptosis is a type of regulated cell death triggered by proinflammatory signals. CCR5 (C-C chemokine receptor 5)-mediated inflammation is involved in the pathology of various neurological diseases. This study investigated the impact of CCR5 activation on neuronal pyroptosis and the underlying mechanism involving cAMP-dependent PKA (protein kinase A)/CREB (cAMP response element binding)/NLRP1 (nucleotide-binding domain leucine-rich repeat pyrin domain containing 1) pathway after experimental intracerebral hemorrhage (ICH).

Methods: A total of 194 adult male CD1 mice were used. ICH was induced by autologous whole blood injection. Maraviroc (MVC)-a selective antagonist of CCR5-was administered intranasally 1 hour after ICH. To elucidate the underlying mechanism, a specific CREB inhibitor, 666-15, was administered intracerebroventricularly before MVC administration in ICH mice. In a set of naive mice, rCCL5 (recombinant chemokine ligand 5) and selective PKA activator, 8-Bromo-cAMP, were administered intracerebroventricularly. Short- and long-term neurobehavioral assessments, Western blot, Fluoro-Jade C, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and immunofluorescence staining were performed.

Results: The brain expression of CCL5 (chemokine ligand 5), CCR5, PKA-Cα (protein kinase A-Cα), p-CREB (phospho-cAMP response element binding), and NLRP1 was increased, peaking at 24 hours after ICH. CCR5 was expressed on neurons, microglia, and astrocytes. MVC improved the short- and long-term neurobehavioral deficits and decreased neuronal pyroptosis in ipsilateral brain tissues at 24 hours after ICH, which were accompanied by increased PKA-Cα and p-CREB expression, and decreased expression of NLRP1, ASC (apoptosis-associated speck-like protein containing a CARD), C-caspase-1, GSDMD (gasdermin D), and IL (interleukin)-1β/IL-18. Such effects of MVC were abolished by 666-15. At 24 hours after injection in naive mice, rCCL5 induced neurological deficits, decreased PKA-Cα and p-CREB expression in the brain, and upregulated NLRP1, ASC, C-caspase-1, N-GSDMD, and IL-1β/IL-18 expression. Those effects of rCCL5 were reversed by 8-Bromo-cAMP.

Conclusions: CCR5 activation promoted neuronal pyroptosis and neurological deficits after ICH in mice, partially through the CCR5/PKA/CREB/NLRP1 signaling pathway. CCR5 inhibition with MVC may provide a promising therapeutic approach in managing patients with ICH.

Keywords: cerebral hemorrhage; chemokine receptor; inflammasome; neuron; pyroptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Apoptosis Regulatory Proteins / metabolism
  • Cerebral Hemorrhage / metabolism
  • Cerebral Hemorrhage / pathology*
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Male
  • Mice
  • Neurons / metabolism
  • Neurons / pathology*
  • Pyroptosis / physiology*
  • Receptors, CCR5 / metabolism*
  • Signal Transduction / physiology

Substances

  • Adaptor Proteins, Signal Transducing
  • Apoptosis Regulatory Proteins
  • CCR5 protein, mouse
  • Creb1 protein, mouse
  • Cyclic AMP Response Element-Binding Protein
  • NALP1 protein, mouse
  • Receptors, CCR5
  • Cyclic AMP-Dependent Protein Kinases