Cellular mechanisms by which proinsulin C-peptide prevents insulin-induced neointima formation in human saphenous vein

R. S. Mughal, J. L. Scragg, P. Lister, P. Warburton, K. Riches, D. J. O'Regan, S. G. Ball, N. A. Turner, K. E. Porter

Research output: Contribution to journalArticle

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Abstract

Aims/hypothesis: Endothelial cells (ECs) and smooth muscle cells (SMCs) play key roles in the development of intimal hyperplasia in saphenous vein (SV) bypass grafts. In diabetic patients, insulin administration controls hyperglycaemia but cardiovascular complications remain. Insulin is synthesised as a pro-peptide, from which C-peptide is cleaved and released into the circulation with insulin; exogenous insulin lacks C-peptide. Here we investigate modulation of human SV neointima formation and SV-EC and SV-SMC function by insulin and C-peptide. Methods: Effects of insulin and C-peptide on neointima formation (organ cultures), EC and SMC proliferation (cell counting), EC migration (scratch wound), SMC migration (Boyden chamber) and signalling (immunoblotting) were examined. A real-time RT-PCR array identified insulin-responsive genes, and results were confirmed by real-time RT-PCR. Targeted gene silencing (siRNA) was used to assess functional relevance. Results: Insulin (100 nmol/l) augmented SV neointimal thickening (70% increase, 14 days), SMC proliferation (55% increase, 7 days) and migration (150% increase, 6 h); effects were abrogated by 10 nmol/l C-peptide. C-peptide did not affect insulin-induced Akt or extracellular signal-regulated kinase signalling (15 min), but array data and gene silencing implicated sterol regulatory element binding transcription factor 1 (SREBF1). Insulin (1-100 nmol/l) did not modify EC proliferation or migration, whereas 10 nmol/l C-peptide stimulated EC proliferation by 40% (5 days). Conclusions/interpretation: Our data support a causative role for insulin in human SV neointima formation with a novel counter-regulatory effect of proinsulin C-peptide. Thus, C-peptide can limit the detrimental effects of insulin on SMC function. Co-supplementing insulin therapy with C-peptide could improve therapy in insulin-treated patients.

Original languageEnglish
Pages (from-to)1761-1771
Number of pages11
JournalDiabetologia
Volume53
Issue number8
DOIs
Publication statusPublished - 1 Aug 2010
Externally publishedYes

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Neointima
C-Peptide
Saphenous Vein
Insulin
Smooth Muscle Myocytes
Endothelial Cells
Cell Proliferation
Cell Movement
Gene Silencing
Real-Time Polymerase Chain Reaction
Tunica Intima
Organ Culture Techniques
Extracellular Signal-Regulated MAP Kinases
Sterols
Immunoblotting
Hyperglycemia
Small Interfering RNA

Cite this

Mughal, R. S. ; Scragg, J. L. ; Lister, P. ; Warburton, P. ; Riches, K. ; O'Regan, D. J. ; Ball, S. G. ; Turner, N. A. ; Porter, K. E. / Cellular mechanisms by which proinsulin C-peptide prevents insulin-induced neointima formation in human saphenous vein. In: Diabetologia. 2010 ; Vol. 53, No. 8. pp. 1761-1771.
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abstract = "Aims/hypothesis: Endothelial cells (ECs) and smooth muscle cells (SMCs) play key roles in the development of intimal hyperplasia in saphenous vein (SV) bypass grafts. In diabetic patients, insulin administration controls hyperglycaemia but cardiovascular complications remain. Insulin is synthesised as a pro-peptide, from which C-peptide is cleaved and released into the circulation with insulin; exogenous insulin lacks C-peptide. Here we investigate modulation of human SV neointima formation and SV-EC and SV-SMC function by insulin and C-peptide. Methods: Effects of insulin and C-peptide on neointima formation (organ cultures), EC and SMC proliferation (cell counting), EC migration (scratch wound), SMC migration (Boyden chamber) and signalling (immunoblotting) were examined. A real-time RT-PCR array identified insulin-responsive genes, and results were confirmed by real-time RT-PCR. Targeted gene silencing (siRNA) was used to assess functional relevance. Results: Insulin (100 nmol/l) augmented SV neointimal thickening (70{\%} increase, 14 days), SMC proliferation (55{\%} increase, 7 days) and migration (150{\%} increase, 6 h); effects were abrogated by 10 nmol/l C-peptide. C-peptide did not affect insulin-induced Akt or extracellular signal-regulated kinase signalling (15 min), but array data and gene silencing implicated sterol regulatory element binding transcription factor 1 (SREBF1). Insulin (1-100 nmol/l) did not modify EC proliferation or migration, whereas 10 nmol/l C-peptide stimulated EC proliferation by 40{\%} (5 days). Conclusions/interpretation: Our data support a causative role for insulin in human SV neointima formation with a novel counter-regulatory effect of proinsulin C-peptide. Thus, C-peptide can limit the detrimental effects of insulin on SMC function. Co-supplementing insulin therapy with C-peptide could improve therapy in insulin-treated patients.",
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Mughal, RS, Scragg, JL, Lister, P, Warburton, P, Riches, K, O'Regan, DJ, Ball, SG, Turner, NA & Porter, KE 2010, 'Cellular mechanisms by which proinsulin C-peptide prevents insulin-induced neointima formation in human saphenous vein', Diabetologia, vol. 53, no. 8, pp. 1761-1771. https://doi.org/10.1007/s00125-010-1736-6

Cellular mechanisms by which proinsulin C-peptide prevents insulin-induced neointima formation in human saphenous vein. / Mughal, R. S.; Scragg, J. L.; Lister, P.; Warburton, P.; Riches, K.; O'Regan, D. J.; Ball, S. G.; Turner, N. A.; Porter, K. E.

In: Diabetologia, Vol. 53, No. 8, 01.08.2010, p. 1761-1771.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Cellular mechanisms by which proinsulin C-peptide prevents insulin-induced neointima formation in human saphenous vein

AU - Mughal, R. S.

AU - Scragg, J. L.

AU - Lister, P.

AU - Warburton, P.

AU - Riches, K.

AU - O'Regan, D. J.

AU - Ball, S. G.

AU - Turner, N. A.

AU - Porter, K. E.

PY - 2010/8/1

Y1 - 2010/8/1

N2 - Aims/hypothesis: Endothelial cells (ECs) and smooth muscle cells (SMCs) play key roles in the development of intimal hyperplasia in saphenous vein (SV) bypass grafts. In diabetic patients, insulin administration controls hyperglycaemia but cardiovascular complications remain. Insulin is synthesised as a pro-peptide, from which C-peptide is cleaved and released into the circulation with insulin; exogenous insulin lacks C-peptide. Here we investigate modulation of human SV neointima formation and SV-EC and SV-SMC function by insulin and C-peptide. Methods: Effects of insulin and C-peptide on neointima formation (organ cultures), EC and SMC proliferation (cell counting), EC migration (scratch wound), SMC migration (Boyden chamber) and signalling (immunoblotting) were examined. A real-time RT-PCR array identified insulin-responsive genes, and results were confirmed by real-time RT-PCR. Targeted gene silencing (siRNA) was used to assess functional relevance. Results: Insulin (100 nmol/l) augmented SV neointimal thickening (70% increase, 14 days), SMC proliferation (55% increase, 7 days) and migration (150% increase, 6 h); effects were abrogated by 10 nmol/l C-peptide. C-peptide did not affect insulin-induced Akt or extracellular signal-regulated kinase signalling (15 min), but array data and gene silencing implicated sterol regulatory element binding transcription factor 1 (SREBF1). Insulin (1-100 nmol/l) did not modify EC proliferation or migration, whereas 10 nmol/l C-peptide stimulated EC proliferation by 40% (5 days). Conclusions/interpretation: Our data support a causative role for insulin in human SV neointima formation with a novel counter-regulatory effect of proinsulin C-peptide. Thus, C-peptide can limit the detrimental effects of insulin on SMC function. Co-supplementing insulin therapy with C-peptide could improve therapy in insulin-treated patients.

AB - Aims/hypothesis: Endothelial cells (ECs) and smooth muscle cells (SMCs) play key roles in the development of intimal hyperplasia in saphenous vein (SV) bypass grafts. In diabetic patients, insulin administration controls hyperglycaemia but cardiovascular complications remain. Insulin is synthesised as a pro-peptide, from which C-peptide is cleaved and released into the circulation with insulin; exogenous insulin lacks C-peptide. Here we investigate modulation of human SV neointima formation and SV-EC and SV-SMC function by insulin and C-peptide. Methods: Effects of insulin and C-peptide on neointima formation (organ cultures), EC and SMC proliferation (cell counting), EC migration (scratch wound), SMC migration (Boyden chamber) and signalling (immunoblotting) were examined. A real-time RT-PCR array identified insulin-responsive genes, and results were confirmed by real-time RT-PCR. Targeted gene silencing (siRNA) was used to assess functional relevance. Results: Insulin (100 nmol/l) augmented SV neointimal thickening (70% increase, 14 days), SMC proliferation (55% increase, 7 days) and migration (150% increase, 6 h); effects were abrogated by 10 nmol/l C-peptide. C-peptide did not affect insulin-induced Akt or extracellular signal-regulated kinase signalling (15 min), but array data and gene silencing implicated sterol regulatory element binding transcription factor 1 (SREBF1). Insulin (1-100 nmol/l) did not modify EC proliferation or migration, whereas 10 nmol/l C-peptide stimulated EC proliferation by 40% (5 days). Conclusions/interpretation: Our data support a causative role for insulin in human SV neointima formation with a novel counter-regulatory effect of proinsulin C-peptide. Thus, C-peptide can limit the detrimental effects of insulin on SMC function. Co-supplementing insulin therapy with C-peptide could improve therapy in insulin-treated patients.

KW - C-peptide

KW - Endothelial cell

KW - Human

KW - Insulin

KW - Migration

KW - Neointima

KW - Proliferation

KW - Saphenous vein

KW - Signalling

KW - Smooth muscle cell

KW - Sterol regulatory element binding transcription factor 1

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U2 - 10.1007/s00125-010-1736-6

DO - 10.1007/s00125-010-1736-6

M3 - Article

VL - 53

SP - 1761

EP - 1771

JO - Diabetologia

JF - Diabetologia

SN - 0012-186X

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ER -