Deciphering microglial activation and neuronal apoptosis post‑traumatic brain injury: The role of TYROBP in inflammation regulation networks

Mol Med Rep. 2024 Jun;29(6):104. doi: 10.3892/mmr.2024.13228. Epub 2024 Apr 19.

Abstract

Traumatic Brain Injury (TBI) represents a significant public health challenge. Recovery from brain injury necessitates the collaborative efforts of various resident neural cells, predominantly microglia. The present study analyzed rat and mouse RNA expression micro‑arrays, high‑throughput RNA sequencing and single‑cell sequencing data sourced from public databases. To construct an inflammation regulation network around TYRO protein tyrosine kinase‑binding protein (TYROBP), to evaluate the role of TYROBP in cell death after TBI. These findings indicate that following TBI, neurons predominantly communicate with one another through the CXC chemokine ligand (CXCL) and CC chemokine ligand (CCL) signaling pathways, employing a paracrine mechanism to activate microglia. These activated microglia intensify the pathological progression of brain injury by releasing factors such as tumor necrosis factor α (TNF‑α), vascular endothelial growth factor and transforming growth factor β via the NF‑κB pathway. Cells co‑culture experiments demonstrated that neurons, impaired by mechanical injury, interact with microglia through non‑contact mechanisms. Activated microglia secrete cytokines, including TNF‑α, CXCL‑8 and CCL2, which trigger an inflammatory response and facilitate neuronal apoptosis. TYROBP gene knockout in microglia was demonstrated to reduce this interaction and reduce neuronal cell apoptosis rates.

Keywords: NF‑κB pathway; TYRO protein tyrosine kinase‑binding protein; inflammatory response; microglia; neuronal cell death; traumatic brain injury.

MeSH terms

  • Adaptor Proteins, Signal Transducing* / metabolism
  • Animals
  • Apoptosis
  • Brain Injuries, Traumatic* / metabolism
  • Inflammation / metabolism
  • Ligands
  • Mice
  • Mice, Inbred C57BL
  • Microglia* / metabolism
  • Protein-Tyrosine Kinases / metabolism
  • Rats
  • Signal Transduction
  • Tumor Necrosis Factor-alpha / metabolism
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Ligands
  • Protein-Tyrosine Kinases
  • Tumor Necrosis Factor-alpha
  • Vascular Endothelial Growth Factor A
  • Tyrobp protein, mouse
  • Adaptor Proteins, Signal Transducing

Grants and funding

This work was funded by the National Natural Science Foundation of China (grant nos. 82071465 and 81571283), the Sanming Project of Medicine in Shenzhen (grant no. SZSM201911007), the Natural Science Foundation of Shandong (grant no. ZR2020MH154), and the Key Project of Research and Development of Shandong Province (grant no. 2018GSF118215).