Journal: Brain sciences

Article Title: Enhanced Interleukin 6 Trans-Signaling Modulates Disease Process in Amyotrophic Lateral Sclerosis Mouse Models.

doi: 10.3390/brainsci15010084

Figure Lengend Snippet: Figure 1. Generation of unique knock-in mouse model C57BL/6 Il6raE357A and IL6R transmembrane deletion (TMD) mouse models. To accurately investigate the potential mechanisms by which IL6 trans-signaling contributes to disease progression, it was necessary to generate a knock-in mouse model C57BL/6 Il6raE357A of IL6 trans-signaling. The mouse Il6ra gene was altered by incorporating a two-base-pair change (AA > CT) at the codon for amino acid 357, thus converting the Glu357 (GAA) to Ala357 (GCT) (A,B). Incorporating this codon change also produced a novel Hind III site that allows us to identify mice heterozygous (HT) or homozygous (HM) for the E357A allele (B). ELISA measurement of soluble IL6 receptor in (C) Il6raE357A mice at P90 (Ala/Ala n = 13; Ala/Glu n = 35; Glu/Glu n = 19; p < 0.001 across genotypes; one-way ANOVA) confirmed increased concentrations of soluble receptor in serum. We also created a unique IL6R transmembrane deletion (TMD) mouse model that exhibits tremendous shedding of the receptor (D). ELISA measurements of soluble IL6 receptor in Il6raTMD mice at P90 (TMD/TMD n = 17; WT/WT n = 16; p < 0.001 across genotypes; one-way ANOVA) are plotted (E). ELISA measurements of plasma IL6 in untreated or LPS-treated (3 ug/g, i.p) WT, E357A homozygous and TMD homozygous mice at indicated time points (F). For each treatment group, P90 sex-matched, littermate WT and Il6ra littermates were used. Littermate, gender-matched animals were used (n = 2–3 groups/treatment group/time point). (G) Shown are representative Western blots of untreated or LPS-treated WT, E357A homozygous (HM) and TMD homozygous liver protein extracts 2 and 24 h after LPS administration. Littermate, gender-matched animals were used per treatment group/time point (liver, brain n = 3; kidney n = 2). Phosphorylated Stat3 and total Stat3 levels were normalized to Hsc70 used as a loading control and the ratio of P-Stat3/total Stat3 determined for each tissue sample. Results are expressed as fold-change in Il6ra over WT littermate. Phosphorylated Stat3 expression increased by 2 h in all animals but was greater in the il6ra models, a pattern observed at 24 h.

Article Snippet: Soluble Il6Ra levels were determined in serum using commercially available ELISA assays (R&D Systems mouse IL6Ra ELISA #MR600, Minneapolis, MN, USA; Figure 1C).

Techniques: Knock-In, Biomarker Discovery, Produced, Enzyme-linked Immunosorbent Assay, Clinical Proteomics, Western Blot, Control, Expressing