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Epigenetic regulation of HDAC1 SUMOylation as an endogenous neuroprotection against A β toxicity in a mouse model of Alzheimer's disease

View Article: PubMed Central - PubMed

ABSTRACT

Amyloid-β (Aβ) produces neurotoxicity in the brain and causes neuronal death, but the endogenous defense mechanism that is activated on Aβ insult is less well known. Here we found that acute Aβ increases the expression of PIAS1 and Mcl-1 via activation of MAPK/ERK, and Aβ induction of PIAS1 enhances HDAC1 SUMOylation in rat hippocampus. Knockdown of PIAS1 decreases endogenous HDAC1 SUMOylation and blocks Aβ induction of Mcl-1. Sumoylated HDAC1 reduces it association with CREB, increases CREB binding to the Mcl-1 promoter and mediates Aβ induction of Mcl-1 expression. Transduction of SUMO-modified lenti-HDAC1 vector to the hippocampus of APP/PS1 mice rescues spatial learning and memory deficit and long-term potentiation impairment in APP/PS1 mice. It also reduces the amount of amyloid plaque and the number of apoptotic cells in CA1 area of APP/PS1 mice. Meanwhile, HDAC1 SUMOylation decreases HDAC1 binding to the neprilysin promoter. These results together reveal an important role of HDAC1 SUMOylation as a naturally occurring defense mechanism protecting against Aβ toxicity and provide an alternative therapeutic strategy against AD.

No MeSH data available.


Acute Aβ increases HDAC1 SUMOylation by PIAS1 in the hippocampus. (a) In vitro SUMOylation assay showing HDAC1 SUMOylation by PIAS1. Recombinant E1, E2 proteins (from the SUMO kit) and purified GST-PIAS1, His-SUMO1, His-HDAC1 and GST-SENP proteins were added to the reaction for this assay. (b) Co-IP experiment showing the association between PIAS1 and HDAC1 in rat hippocampus. (c) Immunohistochemistry showing PIAS1 and HDAC1 are both present in the nucleus of the same neurons in CA1 area of rat brain. N=3. Scale bar, 20 μm (upper panel); 10 μm (lower panel). (d) Co-IP experiment showing the association between PIAS1 and HDAC1 with and without acute Aβ treatment with quantified results (n=3 each group, t1,4=6.5, P<0.01). (e) Effects of knockdown of PIAS1 on endogenous HDAC1 SUMOylation, Mcl-1 and PIAS1 expression in rat hippocampus. (f) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, t1,8=4.02, P<0.01; for Mcl-1, t1,8=11.69, P<0.001; for PIAS1, t1,8=9.6, P<0.001). (g) Effects of Aβ and reverse Aβ on HDAC1 SUMOylation in rat hippocampus (n=5 each group; F2,12=62.07, P<0.001). (h) Effect of knockdown of PIAS1 (with sub-threshold concentration of PIAS1 siRNA) on Aβ induction of HDAC1 SUMOylation in rat hippocampus. (i) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, F3,16=44.88, P<0.001; for PIAS1, F3,16=49.61, P<0.001). rAβ: reverse Aβ. Data are mean±s.e.m. *P<0.05, **P<0.01 and #P<0.001
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fig2: Acute Aβ increases HDAC1 SUMOylation by PIAS1 in the hippocampus. (a) In vitro SUMOylation assay showing HDAC1 SUMOylation by PIAS1. Recombinant E1, E2 proteins (from the SUMO kit) and purified GST-PIAS1, His-SUMO1, His-HDAC1 and GST-SENP proteins were added to the reaction for this assay. (b) Co-IP experiment showing the association between PIAS1 and HDAC1 in rat hippocampus. (c) Immunohistochemistry showing PIAS1 and HDAC1 are both present in the nucleus of the same neurons in CA1 area of rat brain. N=3. Scale bar, 20 μm (upper panel); 10 μm (lower panel). (d) Co-IP experiment showing the association between PIAS1 and HDAC1 with and without acute Aβ treatment with quantified results (n=3 each group, t1,4=6.5, P<0.01). (e) Effects of knockdown of PIAS1 on endogenous HDAC1 SUMOylation, Mcl-1 and PIAS1 expression in rat hippocampus. (f) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, t1,8=4.02, P<0.01; for Mcl-1, t1,8=11.69, P<0.001; for PIAS1, t1,8=9.6, P<0.001). (g) Effects of Aβ and reverse Aβ on HDAC1 SUMOylation in rat hippocampus (n=5 each group; F2,12=62.07, P<0.001). (h) Effect of knockdown of PIAS1 (with sub-threshold concentration of PIAS1 siRNA) on Aβ induction of HDAC1 SUMOylation in rat hippocampus. (i) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, F3,16=44.88, P<0.001; for PIAS1, F3,16=49.61, P<0.001). rAβ: reverse Aβ. Data are mean±s.e.m. *P<0.05, **P<0.01 and #P<0.001

Mentions: The above results showed that acute Aβ treatment increased PIAS1 expression at 24 h later. Because PIAS1 is a SUMO E3 ligase and HDAC1 is implicated in neurodegenerative diseases, here we examined whether HDAC1 could be sumoylated by PIAS1 in the rat brain and whether HDAC1 SUMOylation is modulated by Aβ treatment. We first carried out the in vitro SUMOylation assay. Recombinant E1, E2, and different His- or GST-tagged proteins were added to the reaction and western blot was carried out. Results revealed that HDAC1 SUMOylation was observed when E1, E2, SUMO1 and HDAC1 proteins were present, but HDAC1 SUMOylation was enhanced when the PIAS1 protein was also added. But HDAC1 SUMOylation was completely blocked by the addition of sentrin-specific protease 1 (SENP1), an enzyme that removes the sumo molecule from sumo-conjugated proteins (Figure 2a). We then carried out the co-immunoprecipitation (co-IP) experiment and the result showed that PIAS1 is associated with HDAC1 endogenously in rat CA1 area (Figure 2b). Next, we examined whether PIAS1 and HDAC1 are present in the same neurons in the hippocampus of the rat brain. Brain sections containing the CA1 region were subjected to immunohistochemistry staining. Results revealed that immunofluorescence for PIAS1 (green), HDAC1 (red) and DAPI (blue) was visualized in neurons in the CA1 area (Figure 2c, upper panel). When these CA1 neurons were visualized at a higher magnification, PIAS1 and HDAC1 were found present and co-localized in the nucleus of the same CA1 neurons (Figure 2c, lower panel). We further examined whether Aβ treatment alters the association between PIAS1 and HDAC1. Results revealed that acute Aβ injection increased the association between PIAS1 and HDAC1 in the CA1 area at 1 h later (Figure 2d). The quantitative result is shown in the right panel. These results suggest that HDAC1 is probably SUMO-modified by PIAS1 in the hippocampus and Aβ may increase the SUMOylation of HDAC1 by PIAS1. To test this hypothesis, we have transfected control siRNA and PIAS1 siRNA (8 pmol) to rat CA1 area and endogenous HDAC1 SUMOylation was examined 48 h later. Results revealed that PIAS1 siRNA transfection significantly decreased the level of endogenous HDAC1 SUMOylation when the cell lysate was immunoprecipitated with anti-HDAC1 antibody and immunoblotted with anti-HDAC1 antibody (Figure 2e, left panel) or anti-SUMO1 antibody (Figure 2e, right panel). Meanwhile, PIAS1 siRNA transfection decreased the level of PIAS1 expression and Mcl-1 expression (Figure 2e, lower-left panel). The quantified results are shown in Figure 2f.


Epigenetic regulation of HDAC1 SUMOylation as an endogenous neuroprotection against A β toxicity in a mouse model of Alzheimer's disease
Acute Aβ increases HDAC1 SUMOylation by PIAS1 in the hippocampus. (a) In vitro SUMOylation assay showing HDAC1 SUMOylation by PIAS1. Recombinant E1, E2 proteins (from the SUMO kit) and purified GST-PIAS1, His-SUMO1, His-HDAC1 and GST-SENP proteins were added to the reaction for this assay. (b) Co-IP experiment showing the association between PIAS1 and HDAC1 in rat hippocampus. (c) Immunohistochemistry showing PIAS1 and HDAC1 are both present in the nucleus of the same neurons in CA1 area of rat brain. N=3. Scale bar, 20 μm (upper panel); 10 μm (lower panel). (d) Co-IP experiment showing the association between PIAS1 and HDAC1 with and without acute Aβ treatment with quantified results (n=3 each group, t1,4=6.5, P<0.01). (e) Effects of knockdown of PIAS1 on endogenous HDAC1 SUMOylation, Mcl-1 and PIAS1 expression in rat hippocampus. (f) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, t1,8=4.02, P<0.01; for Mcl-1, t1,8=11.69, P<0.001; for PIAS1, t1,8=9.6, P<0.001). (g) Effects of Aβ and reverse Aβ on HDAC1 SUMOylation in rat hippocampus (n=5 each group; F2,12=62.07, P<0.001). (h) Effect of knockdown of PIAS1 (with sub-threshold concentration of PIAS1 siRNA) on Aβ induction of HDAC1 SUMOylation in rat hippocampus. (i) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, F3,16=44.88, P<0.001; for PIAS1, F3,16=49.61, P<0.001). rAβ: reverse Aβ. Data are mean±s.e.m. *P<0.05, **P<0.01 and #P<0.001
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fig2: Acute Aβ increases HDAC1 SUMOylation by PIAS1 in the hippocampus. (a) In vitro SUMOylation assay showing HDAC1 SUMOylation by PIAS1. Recombinant E1, E2 proteins (from the SUMO kit) and purified GST-PIAS1, His-SUMO1, His-HDAC1 and GST-SENP proteins were added to the reaction for this assay. (b) Co-IP experiment showing the association between PIAS1 and HDAC1 in rat hippocampus. (c) Immunohistochemistry showing PIAS1 and HDAC1 are both present in the nucleus of the same neurons in CA1 area of rat brain. N=3. Scale bar, 20 μm (upper panel); 10 μm (lower panel). (d) Co-IP experiment showing the association between PIAS1 and HDAC1 with and without acute Aβ treatment with quantified results (n=3 each group, t1,4=6.5, P<0.01). (e) Effects of knockdown of PIAS1 on endogenous HDAC1 SUMOylation, Mcl-1 and PIAS1 expression in rat hippocampus. (f) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, t1,8=4.02, P<0.01; for Mcl-1, t1,8=11.69, P<0.001; for PIAS1, t1,8=9.6, P<0.001). (g) Effects of Aβ and reverse Aβ on HDAC1 SUMOylation in rat hippocampus (n=5 each group; F2,12=62.07, P<0.001). (h) Effect of knockdown of PIAS1 (with sub-threshold concentration of PIAS1 siRNA) on Aβ induction of HDAC1 SUMOylation in rat hippocampus. (i) Quantified results are shown (n=5 each group; for HDAC1 SUMOylation, F3,16=44.88, P<0.001; for PIAS1, F3,16=49.61, P<0.001). rAβ: reverse Aβ. Data are mean±s.e.m. *P<0.05, **P<0.01 and #P<0.001
Mentions: The above results showed that acute Aβ treatment increased PIAS1 expression at 24 h later. Because PIAS1 is a SUMO E3 ligase and HDAC1 is implicated in neurodegenerative diseases, here we examined whether HDAC1 could be sumoylated by PIAS1 in the rat brain and whether HDAC1 SUMOylation is modulated by Aβ treatment. We first carried out the in vitro SUMOylation assay. Recombinant E1, E2, and different His- or GST-tagged proteins were added to the reaction and western blot was carried out. Results revealed that HDAC1 SUMOylation was observed when E1, E2, SUMO1 and HDAC1 proteins were present, but HDAC1 SUMOylation was enhanced when the PIAS1 protein was also added. But HDAC1 SUMOylation was completely blocked by the addition of sentrin-specific protease 1 (SENP1), an enzyme that removes the sumo molecule from sumo-conjugated proteins (Figure 2a). We then carried out the co-immunoprecipitation (co-IP) experiment and the result showed that PIAS1 is associated with HDAC1 endogenously in rat CA1 area (Figure 2b). Next, we examined whether PIAS1 and HDAC1 are present in the same neurons in the hippocampus of the rat brain. Brain sections containing the CA1 region were subjected to immunohistochemistry staining. Results revealed that immunofluorescence for PIAS1 (green), HDAC1 (red) and DAPI (blue) was visualized in neurons in the CA1 area (Figure 2c, upper panel). When these CA1 neurons were visualized at a higher magnification, PIAS1 and HDAC1 were found present and co-localized in the nucleus of the same CA1 neurons (Figure 2c, lower panel). We further examined whether Aβ treatment alters the association between PIAS1 and HDAC1. Results revealed that acute Aβ injection increased the association between PIAS1 and HDAC1 in the CA1 area at 1 h later (Figure 2d). The quantitative result is shown in the right panel. These results suggest that HDAC1 is probably SUMO-modified by PIAS1 in the hippocampus and Aβ may increase the SUMOylation of HDAC1 by PIAS1. To test this hypothesis, we have transfected control siRNA and PIAS1 siRNA (8 pmol) to rat CA1 area and endogenous HDAC1 SUMOylation was examined 48 h later. Results revealed that PIAS1 siRNA transfection significantly decreased the level of endogenous HDAC1 SUMOylation when the cell lysate was immunoprecipitated with anti-HDAC1 antibody and immunoblotted with anti-HDAC1 antibody (Figure 2e, left panel) or anti-SUMO1 antibody (Figure 2e, right panel). Meanwhile, PIAS1 siRNA transfection decreased the level of PIAS1 expression and Mcl-1 expression (Figure 2e, lower-left panel). The quantified results are shown in Figure 2f.

View Article: PubMed Central - PubMed

ABSTRACT

Amyloid-&beta; (A&beta;) produces neurotoxicity in the brain and causes neuronal death, but the endogenous defense mechanism that is activated on A&beta; insult is less well known. Here we found that acute A&beta; increases the expression of PIAS1 and Mcl-1 via activation of MAPK/ERK, and A&beta; induction of PIAS1 enhances HDAC1 SUMOylation in rat hippocampus. Knockdown of PIAS1 decreases endogenous HDAC1 SUMOylation and blocks A&beta; induction of Mcl-1. Sumoylated HDAC1 reduces it association with CREB, increases CREB binding to the Mcl-1 promoter and mediates A&beta; induction of Mcl-1 expression. Transduction of SUMO-modified lenti-HDAC1 vector to the hippocampus of APP/PS1 mice rescues spatial learning and memory deficit and long-term potentiation impairment in APP/PS1 mice. It also reduces the amount of amyloid plaque and the number of apoptotic cells in CA1 area of APP/PS1 mice. Meanwhile, HDAC1 SUMOylation decreases HDAC1 binding to the neprilysin promoter. These results together reveal an important role of HDAC1 SUMOylation as a naturally occurring defense mechanism protecting against A&beta; toxicity and provide an alternative therapeutic strategy against AD.

No MeSH data available.