Andras Szabados, Kateryna M. Dukh, Ivanna Ihnatovych, Kinga Szigeti

α7nAChR is a key element of cholinergic anti-inflammatory pathway (CAIP); its activation leads to the inhibition of NF-κB complex. CHRFAM7A, a human-specific gene detected in 99% of the human population is present in different copy numbers and orientation (direct, inverted). The direct allele of CHRFAM7A is translated and gets incorporated into the α7 nAChR. The inverted CHRFAM7A allele is not translated and is a functional null from the α7 nAChR perspective. We have previously shown that the direct allele prolongs NFKB presence in the nucleus in iPSC derived microglia-like cells. We performed a human macrophage ex vivo study (N=70) to characterize NFKB translocation and Il-6 expression on the CHRFAM7A genetic background.

Primary human macrophages were treated with TLR agonists LPS, imiquimod, PAM2CSK4. NF-κB translocation dynamics was quantified over time using Manders’ coefficient. IL-6 expression was measured by ELISA.

In the iPSC model, the direct isogenic MGL cells demonstrated prolonged NF-κB nuclear translocation compared to null in response to LPS. In the human ex vivo model TLR agonists induced NF-κB translocation was prolonged compared to the null MGL on all 3 genetic background: translocation to LPS 4h (direct), 6h (heterozygous), up to 24 h (inverted); response to PAM2CSK4 - 45 min (direct), 2h (heterozygous), 4h (inverted). No NF-κB translocation was detected in response to imiquimod. The level of IL-6 was significantly elevated in response to all treatments, including imiquimod. The presence of both the direct and inverted CHRFAM7A alters the immune response to TLR agonists likely via distinct mechanism.

Department of Neurology, State University of New York at Buffalo, 875 Ellicott St., Buffalo, NY, 14203, USA

Funding Support: Community Foundation for Greater Buffalo (Kinga Szigeti).