NLRP11 Regulation in Adenosine and Hypoxia induced Human Microglia Cell


Taş M., Oylumlu E., Uzel G., Durmus L., Çelik Z., Özçelebi Y., ...More

8th International Congress of the Molecular Biology Association of Turkey (MolBiyoKon’22), İstanbul, Turkey, 9 - 12 June 2022, pp.211

  • Publication Type: Conference Paper / Summary Text
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.211
  • Istanbul Technical University Affiliated: Yes

Abstract

Background/aim: Hypoxia is one of the major causes of brain damage associated with
neurogenerative diseases and cognitive disorientation. During hypoxia, microglia – brain resident
cells – have been shown to involve in a broad spectrum of inflammation process in the brain, one
of which is the contribution of microglia to M1 and M2 differentiation. A member of NOD-like
receptor family, NLRP11 was recently shown to have anti-inflammatory effects on the T helper
cell responses, however its roles and mechanisms of action in the innate immunity are largely
unknown. Therefore, the aim of the study is to examine the microglial NLRP11 expression profile,
and its subsequent impact on the potential inflammation mediated by inflammatory cytokines and
matrix metalloproteinases in human microglia by utilizing HMC3 cells after adenosine and hypoxia
induction.
Materials and methods: HMC3 cells were stimulated with 50,100, 200, 500 and 1000 µM
adenosine for 4 hours and 70, 125, 250 µM CoCl
2 for 8 hours to induce hypoxia. The protein
expression levels of NLRP11, NLRP3, IL-1B, Caspase-1, Akt, phospho-Akt, Nrf2 and acetyl-Nrf2
were analysed by western blotting. Cell viability was confirmed by 7-AAD staining. Next, we
measured the MMP9 enzyme activity by gelatin zymography in response to adenosine treatment.
Results: Since the microglia cells’ activation threshold is 200x higher than macrophages we
included high doses of adenosine in our experiments and tested its effects on cell viability. Our
preliminary data suggest that while high concentrations of adenosine did not affect the cell
viability; both NLRP11 protein expression and MMP9 enzyme activity increased after adenosine
treatment in HMC3 microglia cells in a dose dependent manner, however we did not observe such
an increase in NLRP3 protein expression. Additionally, we investigated the CoCl
2 – induced
hypoxia in HMC3 cells and, showed that, acetylated Nrf2, a marker for oxidative stress, levels
were reduced at increasing doses of CoCl
2.
Conclusion: Our findings report the NLRP11 expression at protein level in HMC3 microglia cells
which makes these cells an ideal model to study NLRP11. Also, results from these study may
suggest a role for NLRP11 in inflammation resolution, thus, it may offer a mechanism of protection
for microglia. We are currently focusing on the measurement of Hif-1 alpha, a marker for hypoxia,
under hypoxic conditions and dissecting the mechanism of action for NLRP11 in microglia cells
in terms of inflammatory responses.
Keywords: Hypoxia, microglia, adenosine, CoCl2, inflammation, NLRP11, MMPs