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. 2019 Jun 6;7(2):253-265.
doi: 10.1016/j.gendis.2019.05.002. eCollection 2020 Jun.

Pioglitazone ameliorates neuronal damage after traumatic brain injury via the PPARγ/NF-κB/IL-6 signaling pathway

Yongbing Deng  1   2 , Xue Jiang  3 , Xiaoyan Deng  3 , Hong Chen  1 , Jie Xu  3 , Zhaosi Zhang  1 , Geli Liu  3 , Zhu Yong  4 , Chengfu Yuan  5 , Xiaochuan Sun  1 , Changdong Wang  3
Affiliations

Pioglitazone ameliorates neuronal damage after traumatic brain injury via the PPARγ/NF-κB/IL-6 signaling pathway

Yongbing Deng et al. Genes Dis. .

Abstract

Traumatic brain injury (TBI) is the major cause of high mortality and disability rates worldwide. Pioglitazone is an activator of peroxisome proliferator-activated receptor-gamma (PPARγ) that can reduce inflammation following TBI. Clinically, neuroinflammation after TBI lacks effective treatment. Although there are many studies on PPARγ in TBI animals, only few could be converted into clinical, since TBI mechanisms in humans and animals are not completely consistent. The present study, provided a potential theoretical basis and therapeutic target for neuroinflammation treatment after TBI. First, we detected interleukin-6 (IL-6), nitric oxide (NO) and Caspase-3 in TBI clinical specimens, confirming a presence of a high expression of inflammatory factors. Western blot (WB), quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) were used to detect PPARγ, IL-6, and p-NF-κB to identify the mechanisms of neuroinflammation. Then, in the rat TBI model, neurobehavioral and cerebral edema levels were investigated after intervention with pioglitazone (PPARγ activator) or T0070907 (PPARγ inhibitor), and PPARγ, IL-6 and p-NF-κB were detected again by qRT-PCR, WB and immunofluorescence (IF). The obtained results revealed that: 1) increased expression of IL-6, NO and Caspase-3 in serum and cerebrospinal fluid in patients after TBI, and decreased PPARγ in brain tissue; 2) pioglitazone could improve neurobehavioral and reduce brain edema in rats after TBI; 3) the protective effect of pioglitazone was achieved by activating PPARγ and reducing NF-κB and IL-6. The neuroprotective effect of pioglitazone on TBI was mediated through the PPARγ/NF-κB/IL-6 pathway.

Keywords: IL-6; PPARγ; Pioglitazone; Traumatic brain injury; p-NF-κB.

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Figures

Figure 1
Figure 1
The schematic illustration of the timeline in all experiments.
Figure 2
Figure 2
Effect of TBI on IL-6, NO and caspase-3 in CSF and serum. Collection of serum and cerebrospinal fluid in patients during the acute phase of TBI (within 6 h) and during the recovery phase (3 months after surgery). (A–B) IL-6 was evaluated using the IL-6 assay kit from CSF and serum samples. (C–D) The NO concentration was evaluated with an assay kit from CSF and serum samples. (E–F) Effect of TBI on caspase-3 production in CSF and serum. Data are expressed as the mean ± SD and asterisks indicate statistically significant differences between the TBI (n = 45) and Normal groups (n = 30). *p < 0.05, **p < 0.01 (t-test).
Figure 3
Figure 3
Pioglitazone improved functional outcomes after CCI and brain edema. (A) Neurological severity score (NSS) tested prior injury, and on the 1st, 3rd, 7th, 14th and 21st days after CCI [n = 6/group, mean ± SD and asterisks indicate statistically significant differences between groups (vertical line); *p < 0.05, **p < 0.01 by two-way ANOVA, NS means no statistically significant differences]. (B) Time latency spent in Morris Water Maze (MWM) test from the 16th to the 21st day after CCI [n = 6/group, mean ± SD and asterisks indicate statistically significant differences between groups (vertical line); *p < 0.05, **p < 0.01 by two-way ANOVA, NS means no statistically significant differences]. (C) Time spent in correct quadrant in spatial learning performance from the 16th to the 21st day after CCI [n = 6/group, mean ± SD and asterisks indicate statistically significant differences between groups (vertical line); *p < 0.05, **p < 0.01 by two-way ANOVA, NS means no statistically significant differences]. (D) Times traveling across platform on MWM test on the 23rd day after CCI [n = 6/group, mean ± SD and asterisks indicate statistically significant differences between groups (horizontal line); *p < 0.05 by one-way ANOVA, NS means no statistically significant differences]. (E) Percentage of brain tissue water content on the 72 h after CCI [n = 6/group, mean ± SD and asterisks indicate statistically significant differences between groups (horizontal line); *p < 0.05 by one-way ANOVA, NS means no statistically significant differences].
Figure 4
Figure 4
TBI impairs PPARγ expression. (A) qRT-PCR analysis of PPARγ gene expression in human brain tissue of TBI and normal group (the TBI surgery patients resected the contusion edge relative to normal brain tissue) brain tissues (n = 25, triplicates per sample, *p < 0.05, t-test). (B) Western blot analysis of PPARγ protein expression in TBI and normal group brain tissues of human (n = 25, triplicates per sample). (C) Quantification of protein levels from immunoblots as in B. The protein levels of PPARγ were normalized to GAPDH (*p < 0.05, t-test). (D) Representative clinical human brain tissue of TBI and normal group brain tissue histologic sections of H&Estaining (upper right and left panel). Representative histologic sections of PPARγ staining. The brown color shows positively stained cells by the PPARγ antibody (lower right and left panel). (E) The IOD SUM of positive cells was compared between the TBI and normal groups of human brain tissue (n = 20, triplicates per sample, *p < 0.05, t-test). (F) The rat brain region examined by immunofluorescence (G)Representative immunofluorescence images of the surrounding cortex (red: PPARγ) on the third day after CCI (n = 6/group, scale bar, 100 μm). (H) Quantitative analysis of the fluorescence intensity from immunofluorescence as in G. Data were analyzed using an appropriate Student's t-test, one-way ANOVA, or two-way ANOVA followed by post hoc Tukey's analysis. Error bars, SEM.; *p < 0.05, **p < 0.01, means statistically significant differences, NS means no statistically significant differences. (I) Representative Western blotting images (n = 6, triplicates per group). (J) Quantification of protein levels from immunoblots as in I. The protein levels of PPARγ were normalized to GAPDH (n = 6/group, mean ± SD and asterisks indicate statistically significant differences between the two groups shown by horizontal line, *p < 0.05, **p < 0.01 by one-way ANOVA, NS means no statistically significant differences).
Figure 5
Figure 5
TBI up-regulates the IL-6 level, pioglitazone rescues the effects of TBI, and the effect of pioglitazone was partially reversed by T0070907. (A) qRT-PCR analysis of IL-6 gene expression in human brain tissue of TBI and normal group brain tissues (n = 25, triplicates per sample, *p < 0.05, t-test). (B) Western blot analysis of IL-6 protein expression in TBI and normal group brain tissues of human (n = 25, triplicates per sample). (C) Quantification of protein levels from immunoblots as in B. The protein levels of IL-6 were normalized to GAPDH (*p < 0.05, t-test). (D) Representative histologic human clinical TBI and normal group brain tissue sections of IL-6 staining. The brown color shows positively stained cells by the IL-6 antibody. (E) The IOD SUM of positive cells was compared among the TBI and control normal of human brain tissue. (n = 20, triplicates per sample, *p < 0.05, t-test). (F) Representative immunofluorescence images of the surrounding cortex (red: IL-6) on the third day after CCI (n = 6/group, scale bar, 100 μm). (G) Quantitative analysis of the fluorescence intensity from immunofluorescence as in F. Data were analyzed using an appropriate Student's t-test, one-way ANOVA, or two-way ANOVA followed by post hoc Tukey's analysis. Error bars, SEM.; *p < 0.05, **p < 0.01, means statistically significant differences, NS means no statistically significant differences. (H) Representative Western blotting images (n = 6, triplicates per group). (I) Quantification of protein levels from immunoblots as in H. The protein levels of IL-6 were normalized to GAPDH (n = 6/group, mean ± SD and asterisks indicate statistically significant differences between the two groups shown by horizontal line, *p < 0.05, **p < 0.01 by one-way ANOVA, NS means no statistically significant differences).
Figure 6
Figure 6
TBI increases the p-NF-κB level and pioglitazone inhibits p-NF-κB protein expression in the TBI rat model. (A) qRT-PCR analysis of p-NF-κB gene expression in human brain tissue of TBI and normal group brain tissues (n = 25, triplicates per sample, *p < 0.05, t-test). (B) Western blot analysis of p-NF-κB protein expression in TBI and normal group brain tissues of human (n = 25, triplicates per sample). (C) Quantification of protein levels from immunoblots as in B. The protein levels of p-NF-κB were normalized to GAPDH (*p < 0.05, t-test). (D) Representative histologic sections of p-NF-κB staining. The brown color shows positively stained cells by the p-NF-κB antibody. (E) The IOD SUM of positive cells was compared between the TBI and normal groups of human brain tissue (n = 20, triplicates per group, *p < 0.05, t-test). (F) Representative immunofluorescence images of the surrounding cortex (red: p-NF-κB) on the third day after CCI (n = 6/group, scale bar, 100 μm). (G) Quantitative analysis of the fluorescence intensity from immunofluorescence as in F. Data were analyzed using an appropriate Student's t-test, one-way ANOVA, or two-way ANOVA followed by post hoc Tukey's analysis. Error bars, SEM.; *p < 0.05 means statistically significant differences, NS means no statistically significant differences. (H) Representative Western blotting images (n = 6, triplicates per group). (I) Quantification of protein levels from immunoblots as in H. The protein levels of p-NF-κB were normalized to GAPDH (n = 6/group, mean ± SD and asterisks indicate statistically significant differences between the two groups shown by horizontal line, *p < 0.05, **p < 0.01 by one-way ANOVA, NS means no statistically significant differences).
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References

    1. Ghaffarpasand F., Torabi S., Rasti A. Effects of cerebrolysin on functional outcome of patients with traumatic brain injury: a systematic review and meta-analysis. Neuropsychiatr Dis Treat. 2018 Dec 27;15:127–135. - PMC - PubMed
    1. Arnett E., Weaver A.M., Woodyard K.C. PPARgamma is critical for Mycobacterium tuberculosis induction of Mcl-1 and limitation of human macrophage apoptosis. PLoS Pathog. 2018;14(6):e1007100. - PMC - PubMed
    1. Cornelius C., Crupi R., Calabrese V. Traumatic brain injury: oxidative stress and neuroprotection. Antioxid Redox Signal. 2013;19(8):836–853. - PubMed
    1. Kurowska P., Chmielinska J., Ptak A. Expression of peroxisome proliferator-activated receptors is regulated by gonadotropins and steroid hormones in in vitro porcine ovarian follicles. J Physiol Pharmacol – Offic J Pol Physiol Soc. 2017;68(6):823–832. - PubMed
    1. Barbiero J.K., Santiago R., Tonin F.S. PPAR-alpha agonist fenofibrate protects against the damaging effects of MPTP in a rat model of Parkinson's disease. Prog Neuropsychopharmacol Biol Psychiatry. 2014;53:35–44. - PubMed