Pleiotrophin regulates microglia-mediated neuroinflammation

Area of Science:

• Neuroscience
• Immunology
• Molecular Biology

Background:

• Pleiotrophin (PTN) is upregulated in various brain disorders with neuroinflammation.
• The role of PTN in modulating neuroinflammation and its interaction with Toll-like receptor 4 (TLR4) remains unclear.

Purpose of the Study:

• To investigate whether PTN modulates neuroinflammation.
• To determine the involvement of TLR4 signaling in PTN-mediated neuroinflammatory responses.

Main Methods:

• Immunohistochemistry was used to assess glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba1) expression in PTN-overexpressing (PTN-Tg) and wild-type (WT) mice.
• Cytokine levels were measured using X-MAP technology.
• The effect of TLR4 antagonist (TAK-242) on lipopolysaccharide (LPS)-induced responses was evaluated.
• Nitric oxide (NO) production in murine BV2 microglial cells treated with PTN and LPS was assessed.

Main Results:

• LPS-induced microglial activation was significantly increased in the prefrontal cortex (PFC) of PTN-Tg mice compared to WT mice.
• Levels of TNF-α, IL-6, and MCP-1 were significantly elevated in the PFC of PTN-Tg mice following LPS administration.
• TAK-242 pretreatment effectively inhibited cytokine increases in both genotypes.
• Co-incubation of BV2 cells with PTN and LPS potentiated NO production.

Conclusions:

• PTN acts as a novel and potent regulator of neuroinflammation.
• PTN potentiates LPS-stimulated microglial activation.
• Targeting PTN signaling pathways presents potential therapeutic avenues for neurological disorders associated with elevated PTN levels and neuroinflammation.