Erythropoietin Enhances Post-ischemic Migration and Phagocytosis and Alleviates the Activation of Inflammasomes in Human Microglial Cells

Eren Arik; Ole Heinisch; Michaela Bienert; Lara Gubeljak; Alexander Slowik; Arno Reich; Jörg B Schulz; Thomas Wilhelm; Michael Huber; Pardes Habib

doi:10.3389/fncel.2022.915348

Erythropoietin Enhances Post-ischemic Migration and Phagocytosis and Alleviates the Activation of Inflammasomes in Human Microglial Cells

Front Cell Neurosci. 2022 Jun 24:16:915348. doi: 10.3389/fncel.2022.915348. eCollection 2022.

Authors

Eren Arik¹, Ole Heinisch¹, Michaela Bienert², Lara Gubeljak¹, Alexander Slowik³, Arno Reich¹, Jörg B Schulz^{1

4}, Thomas Wilhelm⁵, Michael Huber⁵, Pardes Habib^{1

4}

Affiliations

¹ Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany.
² Institute of Molecular and Cellular Anatomy, Medical Faculty, RWTH Aachen University, Aachen, Germany.
³ Department of Anatomy and Cell Biology, Medical Faculty, RWTH Aachen University, Aachen, Germany.
⁴ JARA-BRAIN Institute of Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany.
⁵ Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany.

Abstract

Recombinant human erythropoietin (rhEPO) has been shown to exert anti-apoptotic and anti-inflammatory effects after cerebral ischemia. Inflammatory cytokines interleukin-1β and -18 (IL-1β and IL-18) are crucial mediators of apoptosis and are maturated by multiprotein complexes termed inflammasomes. Microglia are the first responders to post-ischemic brain damage and are a main source of inflammasomes. However, the impact of rhEPO on microglial activation and the subsequent induction of inflammasomes after ischemia remains elusive. To address this, we subjected human microglial clone 3 (HMC-3) cells to various durations of oxygen-glucose-deprivation/reperfusion (OGD/R) to assess the impact of rhEPO on cell viability, metabolic activity, oxidative stress, phagocytosis, migration, as well as on the regulation and activation of the NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes. Administration of rhEPO mitigated OGD/R-induced oxidative stress and cell death. Additionally, it enhanced metabolic activity, migration and phagocytosis of HMC-3. Moreover, rhEPO attenuated post-ischemic activation and regulation of the NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes as well as their downstream effectors CASPASE1 and IL-1β. Pharmacological inhibition of NLRP3 via MCC950 had no effect on the activation of CASPASE1 and maturation of IL-1β after OGD/R, but increased protein levels of NLRP1, NLRC4, and AIM2, suggesting compensatory activities among inflammasomes. We provide evidence that EPO-conveyed anti-inflammatory actions might be mediated via the regulation of the inflammasomes.

Keywords: AIM2; EPO; NLRC4; NLRP1; NLRP3; ROS; inflammation; ischemia-reperfusion.