Antioxidant dietary deficiency induces caspase activation in chick skeletal muscle cells

Abstract

Apoptosis and necrosis are two distinct forms of cell death that can occur in response to different agents and stress conditions. In order to verify if the oxidative stress induced by dietary selenium and vitamin E deficiencies can lead muscle cells to apoptosis, one-day-old chicks were reared using diets differing in their vitamin E (0 or 10 IU/kg) and selenium (0 or 0.15 ppm) supplementation. Chick skeletal muscle tissue was obtained from 28-day-old animals and used to verify apoptosis occurrence based on caspase activity detection and DNA fragmentation. Antioxidant deficiency significantly increased caspase-like activity assessed by the hydrolysis of fluorogenic peptide substrates (Abz-peptidyl-EDDnp) at lambda exc = 320 nm and lambda em = 420 nm. Proteolytic activation was not accompanied by typical internucleosomal DNA fragmentation detected by field inversion gel electrophoresis. Although the general caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp(O-Me) fluoromethyl ketone (Z-VAD-fmk) (0 to 80 muM) did not block caspase-like activity when preincubated for 30 min with muscle homogenates, the hydrolyzed substrates presented the same cleavage profile in HPLC (at the aspartic acid residue) when incubated with the purified recombinant enzyme caspase-3. These data indicate that oxidative stress causes caspase-like activation in muscle cells and suggest that cell death associated with exudative diathesis (dietary deficiency of selenium and vitamin E) can follow the apoptotic pathway.

Gene Expression of Endoplasmic Reticulum Resident Selenoproteins Correlates with Apoptosis in Various Muscles of Se-Deficient Chicks

“…In the +Se chicks, the pectoral muscle had higher expression amounts for 3 of these genes (Selt, Selk, and Sels) than the thigh and/or wing muscle. In the 2Se chicks, the converse was true for these 4 genes, in particular in the early phase of the experiment (d [15][16][17][18][19][20][21][22][23][24][25]. Meanwhile, the -Se chicks had lower expressions of Selt, Selk, and Sels in the pectoral muscle than the +Se chicks had.…”

“…Because they play important roles in regulating intracellular calcium concentration or ER stress (23,24), these proteins may be involved in the Se deficiencyinduced muscle dystrophy. Although dietary Se regulation of these 4 selenoprotein genes was determined in a recent chick study (3), that assay was limited to only the pectoral muscle without looking into the association with the Se deficiencyinduced cell death (25).…”

Dietary implications on mechanisms of sarcopenia: roles of protein, amino acids and antioxidants

“…These components play important roles by contributing to the antioxidant system as cofactors for antioxidant enzymes. Nunes et al [117] reported significantly increased caspase-like activation in chicks fed a vitamin E and selenium-deficient diet. They also demonstrated that caspase-like activation and cell death in skeletal muscle are induced by oxidative stress or an antioxidant-deficient diet.…”

Progesterone induces apoptosis of insulin-secreting cells: insights into the molecular mechanism

“…Caspase activity was confirmed by incubating cell lysates with the caspase inhibitor Z-VAD-fmk (0.1 or 1 mM). Z-VAD-fmk efficiency was tested using purified recombinant caspase 3, as described by Nunes et al (2003Nunes et al ( , 2005.…”