Interleukin-1α Induction in Human Macrophages
Author
Jørgensen, Trine Lykke
Term
4. term
Publication year
2014
Submitted on
2014-06-30
Pages
43
Abstract
Inflammation er kroppens forsvarsreaktion mod fremmede stoffer. Den styres af cytokiner, små signalproteiner som interleukin-1α (IL-1α). Vi undersøgte, hvordan IL-1α reagerer i blodmakrofager fra ti raske voksne, når cellerne udsættes for lipopolysakkarider (LPS), et bakteriemolekyle, der ofte bruges til at efterligne infektion. Vi målte IL-1αs genaktivitet (mRNA) ved at omdanne RNA til cDNA og anvende kvantitativ PCR, og vi målte IL-1α-protein i cellerne med flowcytometri, en fluorescensbaseret metode. Derudover sekventerede vi IL-1α-genet for at lede efter single nucleotide polymorphisms (SNP’er), små DNA-ændringer, der potentielt kan påvirke responsen. Vi fandt stor person-til-person-variation, men også et fælles mønster: IL-1α-mRNA steg hurtigt inden for 2-4 timer efter LPS og forblev højt i op til 20 timer. Statistiske sammenligninger mellem tidspunkter viste ingen signifikante forskelle (P>0.05), hvilket tyder på, at der ikke skete et fald inden for 20 timer. Til gengæld steg IL-1α-proteinet langsomt men støt, med meget signifikante stigninger mellem 0-4 t, 4-8 t og 8-20 t (P<0.000). En kendt SNP blev fundet hos seks af de ti deltagere, men den var ikke forbundet med, hvor stærkt IL-1α reagerede. Resultaterne viser både individuelle forskelle og fælles træk i IL-1α-responsen på LPS og giver grundlag for videre studier af IL-1α i sundhed og sygdom.
Inflammation is the body’s defense reaction to foreign substances. It is guided by cytokines, small signaling proteins such as interleukin-1α (IL-1α). We examined how IL-1α responds in blood macrophages from ten healthy adults when the cells are exposed to lipopolysaccharides (LPS), a bacterial molecule commonly used to mimic infection. We measured IL-1α gene activity (mRNA) by converting RNA to cDNA and using quantitative PCR, and assessed IL-1α protein inside cells by flow cytometry, a fluorescence-based method. We also sequenced the IL-1α gene to look for single nucleotide polymorphisms (SNPs), small DNA changes that might influence the response. We observed substantial person-to-person variability but a shared pattern: IL-1α mRNA rose quickly within 2-4 hours after LPS and then remained high for up to 20 hours. Statistical comparisons across time points showed no significant differences (P>0.05), indicating no decline within 20 hours. In contrast, IL-1α protein increased slowly but steadily, with highly significant stepwise rises between 0-4 h, 4-8 h, and 8-20 h (P<0.000). A known SNP was present in six of the ten participants, but it was not associated with the strength of the IL-1α response. These findings reveal both individual variation and common features of the IL-1α response to LPS and provide a basis for further studies of IL-1α in health and disease.
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