Grass carp (Ctenopharyngodon idella) PACT induces cell apoptosis and activates NF-кB via PKR

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Zhizhen Hu1, Hailing Du1, Gang Lin1

  • 1School of Life Science, Nanchang University, Nanchang, 330031, China.

Fish & Shellfish Immunology
|May 27, 2020
PubMed

Insights

Grass carp PACT (CiPACT) activates PKR, enhancing apoptosis and immune responses to LPS. This fish PACT-PKR interaction is crucial for cellular defense mechanisms.

Area of Science:

  • Immunology
  • Molecular Biology
  • Fish Biology

Background:

  • PKR (dsRNA-dependent protein kinase) is vital for antiviral responses and apoptosis.
  • PACT (PKR activating protein) is a known activator of PKR in mammals.
  • Fish PKR and PACT systems are recognized, but fish PACT function remains largely unknown.

Purpose of the Study:

  • To investigate the function of grass carp PACT (CiPACT) in cellular stress and immune responses.
  • To elucidate the interaction between CiPACT and CiPKR and its downstream effects.
  • To determine the role of CiPACT-PKR pathway in apoptosis and NF-κB activation in fish.

Main Methods:

  • Quantitative analysis of CiPACT and CiPKR gene expression after LPS stimulation.
  • Overexpression of CiPACT in CIK cells to assess effects on p-eIF2α, apoptosis, and Cip65 translocation.
  • Co-immunoprecipitation assays to confirm CiPACT-CiPKR interaction and PKR phosphorylation.
  • Analysis of bcl-2 and bax gene expression in CiPACT-overexpressed and CiPKR-knocked-down cells.

Main Results:

  • CiPACT and CiPKR expression increased significantly upon LPS stimulation, with CiPACT responding earlier.
  • CiPACT overexpression enhanced p-eIF2α levels, induced apoptosis, and promoted Cip65 nuclear translocation.
  • CiPACT directly interacts with CiPKR, leading to CiPKR phosphorylation.
  • CiPACT overexpression altered bcl-2 and bax expression, while CiPKR knockdown reversed these changes.

Conclusions:

  • Fish PACT plays a significant role in the LPS-induced immune response.
  • The mechanism by which fish PACT induces apoptosis and activates NF-κB is dependent on PKR.
  • CiPACT-CiPKR interaction is critical for regulating apoptosis and immune signaling pathways in grass carp.
Keywords:
ApoptosisFishNF-кB pathwayPACTPKR

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