SIRT3 overexpression in rat muscle does not ameliorate peripheral insulin resistance
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SIRT3 overexpression in rat muscle does not ameliorate peripheral insulin resistance. / Osborne, Brenna; Wright, Lauren E.; Brandon, Amanda E.; Stuart, Ella; Small, Lewin; Hoeks, Joris; Schrauwen, Patrick; Sinclair, David A; Montgomery, Magdalene K; Cooney, Gregory J; Turner, Nigel.
I: Journal of Endocrinology, Bind 258, Nr. 3, e220101, 2023.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - SIRT3 overexpression in rat muscle does not ameliorate peripheral insulin resistance
AU - Osborne, Brenna
AU - Wright, Lauren E.
AU - Brandon, Amanda E.
AU - Stuart, Ella
AU - Small, Lewin
AU - Hoeks, Joris
AU - Schrauwen, Patrick
AU - Sinclair, David A
AU - Montgomery, Magdalene K
AU - Cooney, Gregory J
AU - Turner, Nigel
PY - 2023
Y1 - 2023
N2 - Reduced expression of the NAD+-dependent deacetylase, SIRT3, has been associated with insulin resistance and metabolic dysfunction in humans and rodents. In this study we investigated whether specific overexpression of SIRT3 in vivo in skeletal muscle could prevent HFD-induced muscle insulin resistance. To address this we used a muscle-specific adeno-associated virus (AAV) to overexpress SIRT3 in rat tibialis and EDL muscles. Mitochondrial substrate oxidation, substrate switching and oxidative enzyme activity were assessed in skeletal muscle with and without SIRT3 overexpression. Muscle-specific insulin action was also assessed by hyperinsulinaemic-euglycaemic clamps in rats that underwent a 4-week HFD-feeding protocol. Ex vivo functional assays revealed elevated activity of selected SIRT3-target enzymes including hexokinase, isocitrate dehydrogenase and pyruvate dehydrogenase that was associated with an increase in the ability to switch between fatty acid and glucose-derived substrates in muscle with SIRT3 overexpression. However, during the clamp, muscle from rats fed a HFD with increased SIRT3 expression displayed equally impaired glucose uptake and insulin-stimulated glycogen synthesis as the contralateral control muscle. Intramuscular triglyceride content was similarly increased in muscle of high fat fed rats, regardless of SIRT3 status. Thus, despite SIRT3 KO mouse models indicating many beneficial metabolic roles for SIRT3, our findings show that muscle-specific overexpression of SIRT3 has only minor effects on the acute development of skeletal muscle insulin resistance in high fat fed rats.
AB - Reduced expression of the NAD+-dependent deacetylase, SIRT3, has been associated with insulin resistance and metabolic dysfunction in humans and rodents. In this study we investigated whether specific overexpression of SIRT3 in vivo in skeletal muscle could prevent HFD-induced muscle insulin resistance. To address this we used a muscle-specific adeno-associated virus (AAV) to overexpress SIRT3 in rat tibialis and EDL muscles. Mitochondrial substrate oxidation, substrate switching and oxidative enzyme activity were assessed in skeletal muscle with and without SIRT3 overexpression. Muscle-specific insulin action was also assessed by hyperinsulinaemic-euglycaemic clamps in rats that underwent a 4-week HFD-feeding protocol. Ex vivo functional assays revealed elevated activity of selected SIRT3-target enzymes including hexokinase, isocitrate dehydrogenase and pyruvate dehydrogenase that was associated with an increase in the ability to switch between fatty acid and glucose-derived substrates in muscle with SIRT3 overexpression. However, during the clamp, muscle from rats fed a HFD with increased SIRT3 expression displayed equally impaired glucose uptake and insulin-stimulated glycogen synthesis as the contralateral control muscle. Intramuscular triglyceride content was similarly increased in muscle of high fat fed rats, regardless of SIRT3 status. Thus, despite SIRT3 KO mouse models indicating many beneficial metabolic roles for SIRT3, our findings show that muscle-specific overexpression of SIRT3 has only minor effects on the acute development of skeletal muscle insulin resistance in high fat fed rats.
U2 - 10.1530/joe-22-0101
DO - 10.1530/joe-22-0101
M3 - Journal article
VL - 258
JO - Journal of Endocrinology
JF - Journal of Endocrinology
SN - 0022-0795
IS - 3
M1 - e220101
ER -
ID: 357521307