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Systemic Administration of Induced Neural Stem Cells Regulates Complement Activation in Mouse Closed Head Injury Models

View Article: PubMed Central - PubMed

ABSTRACT

Complement activation plays important roles in the pathogenesis of central nervous system (CNS) diseases. Patients face neurological disorders due to the development of complement activation, which contributes to cell apoptosis, brain edema, blood-brain barrier dysfunction and inflammatory infiltration. We previously reported that induced neural stem cells (iNSCs) can promote neurological functional recovery in closed head injury (CHI) animals. Remarkably, we discovered that local iNSC grafts have the potential to modulate CNS inflammation post-CHI. In this study, we aimed to explore the role of systemically delivered iNSCs in complement activation following CNS injury. Our data showed that iNSC grafts decreased the levels of sera C3a and C5a and down-regulated the expression of C3d, C9, active Caspase-3 and Bax in the brain, kidney and lung tissues of CHI mice. Furthermore, iNSC grafts decreased the levels of C3d+/NeuN+, C5b-9+/NeuN+, C3d+/Map2+ and C5b-9+/Map2+ neurons in the injured cortices of CHI mice. Subsequently, we explored the mechanisms underlying these effects. With flow cytometry analysis, we observed a dramatic increase in complement receptor type 1-related protein y (Crry) expression in iNSCs after CHI mouse serum treatment. Moreover, both in vitro and in vivo loss-of-function studies revealed that iNSCs could modulate complement activation via Crry expression.

No MeSH data available.


INSC grafts decreased the levels of sera C3a and C5a and down-regulated the expression of C3d, C9, active Caspase-3 and Bax in the brain, kidney and lung tissues of CHI mice.(a,b) Histograms showed the levels of sera C3a (a) and C5a (b) among the PBS, iNSC and sham groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (c) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the brain among the three groups on day 7 post-CHI. (d–g) Histograms showed the relative levels of C3d (d), C9 (e), active Caspase-3 (f), and Bax (g) in the brain among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (h) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the kidney among the three groups on day 7 post-CHI. (i–l) Histograms showed the relative levels of C3d (i), C9 (j), active Caspase-3 (k), and Bax (l) in the kidney among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (m) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the lung among the three groups on day 7 post-CHI. (n–q) Histograms showed the relative levels of C3d (n), C9 (o), active Caspase-3 (p), and Bax (q) in the lung among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group).
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f1: INSC grafts decreased the levels of sera C3a and C5a and down-regulated the expression of C3d, C9, active Caspase-3 and Bax in the brain, kidney and lung tissues of CHI mice.(a,b) Histograms showed the levels of sera C3a (a) and C5a (b) among the PBS, iNSC and sham groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (c) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the brain among the three groups on day 7 post-CHI. (d–g) Histograms showed the relative levels of C3d (d), C9 (e), active Caspase-3 (f), and Bax (g) in the brain among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (h) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the kidney among the three groups on day 7 post-CHI. (i–l) Histograms showed the relative levels of C3d (i), C9 (j), active Caspase-3 (k), and Bax (l) in the kidney among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (m) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the lung among the three groups on day 7 post-CHI. (n–q) Histograms showed the relative levels of C3d (n), C9 (o), active Caspase-3 (p), and Bax (q) in the lung among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group).

Mentions: CHI models were established using a standardized weight-drop device23. At 12 h after CHI, mice received an intravenous injection of 5 × 106 cells. On day 7 post-CHI, GFP-expressing iNSCs were detected in the brain, spleen, kidney, liver and lung (Supplementary Table S1). To study the effect of iNSC grafts on complement activation after CNS trauma, we evaluated serum concentrations of C3a and C5a (Fig. 1a,b). Serum C3a and C5a levels were significantly higher in the CHI group than in the sham group (n = 6/group, P < 0.05). Moreover, in contrast to PBS treatment, iNSC administration attenuated CHI-induced increases in serum C3a and C5a levels (P < 0.05).


Systemic Administration of Induced Neural Stem Cells Regulates Complement Activation in Mouse Closed Head Injury Models
INSC grafts decreased the levels of sera C3a and C5a and down-regulated the expression of C3d, C9, active Caspase-3 and Bax in the brain, kidney and lung tissues of CHI mice.(a,b) Histograms showed the levels of sera C3a (a) and C5a (b) among the PBS, iNSC and sham groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (c) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the brain among the three groups on day 7 post-CHI. (d–g) Histograms showed the relative levels of C3d (d), C9 (e), active Caspase-3 (f), and Bax (g) in the brain among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (h) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the kidney among the three groups on day 7 post-CHI. (i–l) Histograms showed the relative levels of C3d (i), C9 (j), active Caspase-3 (k), and Bax (l) in the kidney among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (m) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the lung among the three groups on day 7 post-CHI. (n–q) Histograms showed the relative levels of C3d (n), C9 (o), active Caspase-3 (p), and Bax (q) in the lung among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group).
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f1: INSC grafts decreased the levels of sera C3a and C5a and down-regulated the expression of C3d, C9, active Caspase-3 and Bax in the brain, kidney and lung tissues of CHI mice.(a,b) Histograms showed the levels of sera C3a (a) and C5a (b) among the PBS, iNSC and sham groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (c) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the brain among the three groups on day 7 post-CHI. (d–g) Histograms showed the relative levels of C3d (d), C9 (e), active Caspase-3 (f), and Bax (g) in the brain among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (h) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the kidney among the three groups on day 7 post-CHI. (i–l) Histograms showed the relative levels of C3d (i), C9 (j), active Caspase-3 (k), and Bax (l) in the kidney among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group). (m) Representative immunoblots depicted the levels of C3d, C9, active Caspase-3 and Bax in the lung among the three groups on day 7 post-CHI. (n–q) Histograms showed the relative levels of C3d (n), C9 (o), active Caspase-3 (p), and Bax (q) in the lung among the three groups on day 7 post-CHI (n = 6/group; (a) P < 0.05 versus iNSC group; (b) P < 0.05 versus sham group).
Mentions: CHI models were established using a standardized weight-drop device23. At 12 h after CHI, mice received an intravenous injection of 5 × 106 cells. On day 7 post-CHI, GFP-expressing iNSCs were detected in the brain, spleen, kidney, liver and lung (Supplementary Table S1). To study the effect of iNSC grafts on complement activation after CNS trauma, we evaluated serum concentrations of C3a and C5a (Fig. 1a,b). Serum C3a and C5a levels were significantly higher in the CHI group than in the sham group (n = 6/group, P < 0.05). Moreover, in contrast to PBS treatment, iNSC administration attenuated CHI-induced increases in serum C3a and C5a levels (P < 0.05).

View Article: PubMed Central - PubMed

ABSTRACT

Complement activation plays important roles in the pathogenesis of central nervous system (CNS) diseases. Patients face neurological disorders due to the development of complement activation, which contributes to cell apoptosis, brain edema, blood-brain barrier dysfunction and inflammatory infiltration. We previously reported that induced neural stem cells (iNSCs) can promote neurological functional recovery in closed head injury (CHI) animals. Remarkably, we discovered that local iNSC grafts have the potential to modulate CNS inflammation post-CHI. In this study, we aimed to explore the role of systemically delivered iNSCs in complement activation following CNS injury. Our data showed that iNSC grafts decreased the levels of sera C3a and C5a and down-regulated the expression of C3d, C9, active Caspase-3 and Bax in the brain, kidney and lung tissues of CHI mice. Furthermore, iNSC grafts decreased the levels of C3d+/NeuN+, C5b-9+/NeuN+, C3d+/Map2+ and C5b-9+/Map2+ neurons in the injured cortices of CHI mice. Subsequently, we explored the mechanisms underlying these effects. With flow cytometry analysis, we observed a dramatic increase in complement receptor type 1-related protein y (Crry) expression in iNSCs after CHI mouse serum treatment. Moreover, both in vitro and in vivo loss-of-function studies revealed that iNSCs could modulate complement activation via Crry expression.

No MeSH data available.