Related Experiment Video
Updated: Jul 16, 2025
An In vitro Model to Study Heterogeneity of Human Macrophage Differentiation and Polarization
Published on: June 12, 2013
Effect of Differently Polarized Human Macrophages on the SH-SY5Y Cells Damaged by Ischemia and Hypoxia In Vitro
Ivan Mikhailovich Rashchupkin1, Ekaterina Yakovlevna Shevela1, Aleksandra Aleksandrovna Maksimova1
1Scientific Research Institute of Fundamental and Clinical Immunology, Novosibirsk, Russia.
Abstract:
Macrophages are the major cells of innate immunity with a wide range of biological effects due to their great plasticity and heterogeneity. Macrophages play a key role in neuroregeneration following nervous tissue injury. However, the neuroregenerative potential of various macrophage phenotypes, including those polarized by efferocytosis, remains unexplored. The aim of this study was to compare the neuroregenerative and neuroprotective activity of soluble factors secreted by variously activated human macrophages on the functions of neural progenitors in an in vitro model of ischemia or ischemia/hypoxia. Macrophages were polarized by interferon-γ (M1), IL-4 (M2a), or interaction with apoptotic cells (M2(LS)). The effect of macrophages conditioned media on the proliferation, differentiation, and survival of SH-SY5Y cells damaged by serum deprivation alone (ischemic conditions) or in combination with CoCl2 (ischemic/hypoxic conditions) was assessed. All studied macrophages stimulated the proliferation and differentiation of SH-SY5Y cells. On day 3, the pro-proliferating effect of M1 and M2 was similar and did not depend on the severity of the damaging effect (ischemia or ischemia/hypoxia), while on day 7 and under ischemic/hypoxic conditions, the effects of M2(LS) exceeded those of M1 and M2a cells. The prodifferentiation effects of macrophages were manifested in both short- and long-term cultures, mainly under ischemic/hypoxic conditions, and were most characteristic of M2(LS) cells. Importantly, the ischemia/hypoxia model was accompanied by the pronounced death of SH-SY5Y cells. Only macrophages with the M2 phenotype demonstrated antiapoptotic activity, and the effect of M2(LS) was higher than that of M2a. The results obtained indicate that human macrophages have neuroprotective and neuroregenerative activity, which is mediated by soluble factors, is most characteristic for macrophages activated by efferocytosis (M2(LS)), and is most prominent under in vitro conditions simulating the combined effect of ischemia/hypoxia.
Insights
Human macrophages, particularly those activated by efferocytosis (M2(LS)), secrete factors that promote neural progenitor cell survival, proliferation, and differentiation, offering neuroprotective and neuroregenerative benefits in models of ischemia and hypoxia.
Area of Science:
- Immunology
- Neuroscience
- Cell Biology
Background:
- Macrophages are key innate immune cells with diverse roles, including neuroregeneration.
- The neuroregenerative potential of specific macrophage phenotypes, especially those influenced by efferocytosis, requires further investigation.
Purpose of the Study:
- To compare the neuroregenerative and neuroprotective effects of soluble factors from variously activated human macrophages on neural progenitors.
- To assess these effects in in vitro models simulating ischemia and ischemia/hypoxia.
Main Methods:
- Human macrophages were polarized into M1 (interferon-gamma), M2a (IL-4), and M2(LS) (apoptotic cell interaction) phenotypes.
- Conditioned media from these macrophages were applied to SH-SY5Y neural progenitor cells subjected to serum deprivation (ischemia) or serum deprivation plus CoCl2 (ischemia/hypoxia).
- Effects on proliferation, differentiation, and survival were evaluated.
Main Results:
- All macrophage types enhanced SH-SY5Y proliferation and differentiation.
- M2(LS) macrophages showed superior pro-proliferating effects by day 7 under ischemic/hypoxic conditions compared to M1 and M2a.
- M2(LS) macrophages exhibited the most potent prodifferentiation effects, especially under ischemic/hypoxic stress.
- Only M2 phenotype macrophages (M2(LS) > M2a) demonstrated significant anti-apoptotic activity, protecting SH-SY5Y cells from death.
Conclusions:
- Human macrophages possess neuroprotective and neuroregenerative capabilities mediated by secreted soluble factors.
- Macrophage activation via efferocytosis (M2(LS) phenotype) yields the most significant neuroprotective and neuroregenerative effects.
- These beneficial effects are most pronounced under conditions mimicking combined ischemia and hypoxia.
