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Hydrolysis of 2'3'-cGAMP by ENPP1 and design of nonhydrolyzable analogs.

Li L, Yin Q, Kuss P, Maliga Z, Millán JL, Wu H, Mitchison TJ - Nat. Chem. Biol. (2014)

Bottom Line: We report activity-guided partial purification and identification of ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP1) to be the dominant 2'3'-cGAMP hydrolyzing activity in cultured cells.We synthesized a hydrolysis-resistant bisphosphothioate analog of 2'3'-cGAMP (2'3'-cG(s)A(s)MP) that has similar affinity for hSTING in vitro and is ten times more potent at inducing IFN-β secretion from human THP1 monocytes.Studies in mouse Enpp1(-/-) lung fibroblasts indicate that resistance to hydrolysis contributes substantially to its higher potency. 2'3'-cG(s)A(s)MP is therefore improved over natural 2'3'-cGAMP as a model agonist and has potential as a vaccine adjuvant and cancer therapeutic.

View Article: PubMed Central - PubMed

Affiliation: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA.

ABSTRACT
Agonists of mouse STING (TMEM173) shrink and even cure solid tumors by activating innate immunity; human STING (hSTING) agonists are needed to test this therapeutic hypothesis in humans. The endogenous STING agonist is 2'3'-cGAMP, a second messenger that signals the presence of cytosolic double-stranded DNA. We report activity-guided partial purification and identification of ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP1) to be the dominant 2'3'-cGAMP hydrolyzing activity in cultured cells. The hydrolysis activity of ENPP1 was confirmed using recombinant protein and was depleted in tissue extracts and plasma from Enpp1(-/-) mice. We synthesized a hydrolysis-resistant bisphosphothioate analog of 2'3'-cGAMP (2'3'-cG(s)A(s)MP) that has similar affinity for hSTING in vitro and is ten times more potent at inducing IFN-β secretion from human THP1 monocytes. Studies in mouse Enpp1(-/-) lung fibroblasts indicate that resistance to hydrolysis contributes substantially to its higher potency. 2'3'-cG(s)A(s)MP is therefore improved over natural 2'3'-cGAMP as a model agonist and has potential as a vaccine adjuvant and cancer therapeutic.

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ENPP1 is the dominant hydrolase activity for 2′3′-cGAMP(a) Knockdown of ENPP1 in MDA-MB231 cells diminished hydrolase activity. Four siRNA oligos against ENPP1 with a control siRNA sequence against PDE12 were used. 4 days after siRNA transfection, cells were lysed and assayed for activity (upper panel) and blotted for ENPP1 level (lower level). (b) Hydrolase activity in plasma from Enpp1-/- mice and their littermates. (c) Western blot characterization of Enpp1-/- mice. (d) Hydrolase activity in livers and spleens from Enpp1-/- mice and their littermates. Livers and spleens were minced and Dounce homogenized in lysis buffer: 1% NP-40, 20 mM Tris-HCl, pH 7.5, protease inhibitor cocktail. The assay was conducted in 0.2% NP-40, 20 mM Tris-HCl, 150 mM KCl, 2 mM Ca2+, 2 mM Mg2+, 200 μM Zn2+ at the indicated pH. NaOAc buffer was used for pH 5.0-6.0; PIPES buffer was used for pH 6.5 and 7.0 and 2′3′-cGAMP runs at a lower Rf in this buffer; Tris-HCl buffer was used for pH 7.5-9.0, and Borate buffer was used pH 9.5. These buffer conditions were also used in liver and spleen extract studies.
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Figure 3: ENPP1 is the dominant hydrolase activity for 2′3′-cGAMP(a) Knockdown of ENPP1 in MDA-MB231 cells diminished hydrolase activity. Four siRNA oligos against ENPP1 with a control siRNA sequence against PDE12 were used. 4 days after siRNA transfection, cells were lysed and assayed for activity (upper panel) and blotted for ENPP1 level (lower level). (b) Hydrolase activity in plasma from Enpp1-/- mice and their littermates. (c) Western blot characterization of Enpp1-/- mice. (d) Hydrolase activity in livers and spleens from Enpp1-/- mice and their littermates. Livers and spleens were minced and Dounce homogenized in lysis buffer: 1% NP-40, 20 mM Tris-HCl, pH 7.5, protease inhibitor cocktail. The assay was conducted in 0.2% NP-40, 20 mM Tris-HCl, 150 mM KCl, 2 mM Ca2+, 2 mM Mg2+, 200 μM Zn2+ at the indicated pH. NaOAc buffer was used for pH 5.0-6.0; PIPES buffer was used for pH 6.5 and 7.0 and 2′3′-cGAMP runs at a lower Rf in this buffer; Tris-HCl buffer was used for pH 7.5-9.0, and Borate buffer was used pH 9.5. These buffer conditions were also used in liver and spleen extract studies.

Mentions: To test whether ENPP1 accounts for the dominant hydrolase activity in cells, we performed knockdown experiments in MDA-MB231 cells. siRNA oligos 7-9 against ENPP1 efficiently knocked down ENPP1 protein level and also significantly reduced the hydrolase activity in the whole cell lysate. Oligo 6 and control siRNA against PDE12 did not affect ENPP1 protein level and also did not change the hydrolase activity. These results indicate that the dominant 2′3′-cGAMP hydrolase in this cell line is ENPP1 (Fig. 3a).


Hydrolysis of 2'3'-cGAMP by ENPP1 and design of nonhydrolyzable analogs.

Li L, Yin Q, Kuss P, Maliga Z, Millán JL, Wu H, Mitchison TJ - Nat. Chem. Biol. (2014)

ENPP1 is the dominant hydrolase activity for 2′3′-cGAMP(a) Knockdown of ENPP1 in MDA-MB231 cells diminished hydrolase activity. Four siRNA oligos against ENPP1 with a control siRNA sequence against PDE12 were used. 4 days after siRNA transfection, cells were lysed and assayed for activity (upper panel) and blotted for ENPP1 level (lower level). (b) Hydrolase activity in plasma from Enpp1-/- mice and their littermates. (c) Western blot characterization of Enpp1-/- mice. (d) Hydrolase activity in livers and spleens from Enpp1-/- mice and their littermates. Livers and spleens were minced and Dounce homogenized in lysis buffer: 1% NP-40, 20 mM Tris-HCl, pH 7.5, protease inhibitor cocktail. The assay was conducted in 0.2% NP-40, 20 mM Tris-HCl, 150 mM KCl, 2 mM Ca2+, 2 mM Mg2+, 200 μM Zn2+ at the indicated pH. NaOAc buffer was used for pH 5.0-6.0; PIPES buffer was used for pH 6.5 and 7.0 and 2′3′-cGAMP runs at a lower Rf in this buffer; Tris-HCl buffer was used for pH 7.5-9.0, and Borate buffer was used pH 9.5. These buffer conditions were also used in liver and spleen extract studies.
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Related In: Results  -  Collection

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Figure 3: ENPP1 is the dominant hydrolase activity for 2′3′-cGAMP(a) Knockdown of ENPP1 in MDA-MB231 cells diminished hydrolase activity. Four siRNA oligos against ENPP1 with a control siRNA sequence against PDE12 were used. 4 days after siRNA transfection, cells were lysed and assayed for activity (upper panel) and blotted for ENPP1 level (lower level). (b) Hydrolase activity in plasma from Enpp1-/- mice and their littermates. (c) Western blot characterization of Enpp1-/- mice. (d) Hydrolase activity in livers and spleens from Enpp1-/- mice and their littermates. Livers and spleens were minced and Dounce homogenized in lysis buffer: 1% NP-40, 20 mM Tris-HCl, pH 7.5, protease inhibitor cocktail. The assay was conducted in 0.2% NP-40, 20 mM Tris-HCl, 150 mM KCl, 2 mM Ca2+, 2 mM Mg2+, 200 μM Zn2+ at the indicated pH. NaOAc buffer was used for pH 5.0-6.0; PIPES buffer was used for pH 6.5 and 7.0 and 2′3′-cGAMP runs at a lower Rf in this buffer; Tris-HCl buffer was used for pH 7.5-9.0, and Borate buffer was used pH 9.5. These buffer conditions were also used in liver and spleen extract studies.
Mentions: To test whether ENPP1 accounts for the dominant hydrolase activity in cells, we performed knockdown experiments in MDA-MB231 cells. siRNA oligos 7-9 against ENPP1 efficiently knocked down ENPP1 protein level and also significantly reduced the hydrolase activity in the whole cell lysate. Oligo 6 and control siRNA against PDE12 did not affect ENPP1 protein level and also did not change the hydrolase activity. These results indicate that the dominant 2′3′-cGAMP hydrolase in this cell line is ENPP1 (Fig. 3a).

Bottom Line: We report activity-guided partial purification and identification of ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP1) to be the dominant 2'3'-cGAMP hydrolyzing activity in cultured cells.We synthesized a hydrolysis-resistant bisphosphothioate analog of 2'3'-cGAMP (2'3'-cG(s)A(s)MP) that has similar affinity for hSTING in vitro and is ten times more potent at inducing IFN-β secretion from human THP1 monocytes.Studies in mouse Enpp1(-/-) lung fibroblasts indicate that resistance to hydrolysis contributes substantially to its higher potency. 2'3'-cG(s)A(s)MP is therefore improved over natural 2'3'-cGAMP as a model agonist and has potential as a vaccine adjuvant and cancer therapeutic.

View Article: PubMed Central - PubMed

Affiliation: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA.

ABSTRACT
Agonists of mouse STING (TMEM173) shrink and even cure solid tumors by activating innate immunity; human STING (hSTING) agonists are needed to test this therapeutic hypothesis in humans. The endogenous STING agonist is 2'3'-cGAMP, a second messenger that signals the presence of cytosolic double-stranded DNA. We report activity-guided partial purification and identification of ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP1) to be the dominant 2'3'-cGAMP hydrolyzing activity in cultured cells. The hydrolysis activity of ENPP1 was confirmed using recombinant protein and was depleted in tissue extracts and plasma from Enpp1(-/-) mice. We synthesized a hydrolysis-resistant bisphosphothioate analog of 2'3'-cGAMP (2'3'-cG(s)A(s)MP) that has similar affinity for hSTING in vitro and is ten times more potent at inducing IFN-β secretion from human THP1 monocytes. Studies in mouse Enpp1(-/-) lung fibroblasts indicate that resistance to hydrolysis contributes substantially to its higher potency. 2'3'-cG(s)A(s)MP is therefore improved over natural 2'3'-cGAMP as a model agonist and has potential as a vaccine adjuvant and cancer therapeutic.

Show MeSH
Related in: MedlinePlus