Roquet et al (9) reported that cellular -tocopherol concentrations of red blood cells from Holstein calves were approximately 5 times higher in vitamin E-supplemented calves than in control calves. is recognized by PROTAC FLT-3 degrader 1 SR-BI on the surface of neutrophils, and 3) rearrangement of the actin cytoskeleton is a crucial step for the uptake of -tocopherol by neutrophils. Rsum On a examin les effets dun supplment de vitamine E sur les concentrations cellulaires d-tocophrol des neutrophiles provenant de veaux Holstein et le mcanisme de prise d-tocophrol mdi par les rcepteurs ramasseurs de classe B type I (SR-BI). Les concentrations cellulaires d-tocophrol chez les veaux traits avec de la vitamine E ont augment de 3,5 0,38 7,2 0,84 g/107 cellules, respectivement, lintrieur dun dlai de 14 j aprs une supplmentation en vitamine E; ces concentrations taient significativement plus leves que celles des veaux tmoins ( 0,01). Les taux dexpression dARNm de SR-BI [un rcepteur majeur qui reconna?t les lipoprotines de haute-densit (HDL)] dans les neutrophiles taient 2 5 fois plus levs ( 0,01) dans les neutrophiles obtenus de veaux ayant re?u un supplment de vitamine E comparativement ceux des veaux tmoins, et des anticorps anti-SR-B1, allant de 0,1 1,0 g/mL, ont rduit significativement ( 0,01) les concentrations cellulaires d-tocophrol des neutrophiles. La cytochalasine D et la latrunculine B, des inhibiteurs majeurs de la polymrisation de lactine des neutrophiles, ont diminu de manire significative les concentrations cellulaires d-tocophrol des neutrophiles ( 0,01). Nos rsultats ont dmontr que chez les veaux recevant un supplment de vitamine E : 1) l-tocophrol est principalement distribu avec les HDL, 2) l-tocophrol dans les HDL est reconnu par les SR-BI sur la surface des neutrophiles, et 3) le rarrangement du cytosquelette dactine est une tape cruciale pour la prise d-tocophrol par les neutrophiles. (Traduit par Docteur Serge Messier) Introduction Vitamin E is an integral component of all lipid membranes and protects them from attack by reactive oxygen species (ROS) (1,2). Polyunsaturated fatty acids of membranes are vulnerable to attack by ROS, which can initiate a chain reaction of lipid destruction that destroys the membrane of the cell. Vitamin E can quench peroxidation reactions in membranes and is probably the most important antioxidant present in cell membranes (3). The newborn dairy calf has minimal reserves of lipid-soluble vitamins and fetal uptake is limited (4,5). Vitamin E supplementation has been shown to have positive effects on the immune system of young dairy calves (6,7). We have reported that providing vitamin E supplementation to newborn calves activates killing ability and intracellular signal transduction, including protein kinase C, intracellular Ca2+, and tyrosine kinase of neutrophils (8). It has been reported that cellular -tocopherol concentrations of red blood cells were approximately 5 times higher in vitamin E-supplemented Holstein calves than in control calves (9). However, levels of alpha ()-tocopherol concentration in neutrophils from calves have not yet been examined. The cellular uptake of -tocopherol within high-density lipoprotein (HDL) is reported to be mediated by scavenger receptor class B, type I (SR-BI) (10,11). Moreover, a previous study using SR-BI-deficient mice has shown a deficiency in the uptake of -tocopherol from plasma lipoproteins to specific tissues (12). Rajapaksha et al (13) sequenced the bovine SR-BI and examined changes in expression of messenger ribonucleic acid (mRNA) of SR-BI during development and granulosa cell luteinization Sequencing of the bovine HDL-receptor showed that it codes for a protein of 509 amino acids with close identity to hamster, mouse, rat, and human sequences (13). Examination of the tissue distribution of the HDL-receptor mRNA showed high levels in adrenal cortex and and lower levels in spleen and liver (13). However, expression levels of SR-BI mRNA and the mechanism for SR-BI-mediated uptake PROTAC FLT-3 degrader 1 of -tocopherol have not been clarified with bovine neutrophils. It has been reported that cytochalasin D, latrunculin B, and jasplakinolide are chemical reagents for actin polymerization of neutrophils and were effective in determining if the rearrangement of the neutrophil cytoskeleton is related to the uptake of -tocopherol (14C16). In this study, we examined the effects of vitamin E supplementation on the cellular -tocopherol concentrations of neutrophils from Holstein calves and the mechanism for SR-BI-mediated uptake of -tocopherol. Materials and methods Calves Fourteen newborn Holstein calves were.Blood samples were collected on the day of supplementation (0 d) and 1, 3, 7, 14, 21, and 28 d after supplementation. Isolation of neutrophils Neutrophils were isolated from heparinized blood by Ficoll-Conray solution (specific gravity 1.078), followed by hypotonic red blood cell lysis, as described in a previous paper (17). -tocopherol is mainly distributed with HDL, 2) -tocopherol within HDL is recognized by SR-BI on the surface of neutrophils, and 3) rearrangement of the actin cytoskeleton is a crucial step for the uptake of -tocopherol by neutrophils. Rsum On a examin les effets dun supplment de vitamine E sur les concentrations cellulaires d-tocophrol des neutrophiles provenant de veaux Holstein et le mcanisme de prise d-tocophrol mdi par les rcepteurs ramasseurs de classe B type I (SR-BI). Les concentrations cellulaires d-tocophrol chez les veaux traits avec de la vitamine E ont augment de 3,5 0,38 7,2 0,84 g/107 cellules, respectivement, lintrieur dun dlai de 14 j aprs une supplmentation en vitamine E; ces concentrations taient significativement plus leves que celles des veaux tmoins ( 0,01). Les taux dexpression dARNm de SR-BI [un rcepteur majeur qui reconna?t les lipoprotines de haute-densit (HDL)] dans les neutrophiles taient 2 5 fois plus levs ( 0,01) dans les neutrophiles obtenus de veaux ayant re?u un supplment de vitamine E comparativement ceux des veaux tmoins, et des anticorps anti-SR-B1, allant de 0,1 1,0 g/mL, ont rduit significativement ( 0,01) les concentrations cellulaires d-tocophrol des neutrophiles. La cytochalasine D et la latrunculine B, des inhibiteurs majeurs de la polymrisation de lactine des neutrophiles, ont diminu de manire significative les concentrations cellulaires d-tocophrol des neutrophiles ( 0,01). Nos rsultats ont dmontr que chez les veaux recevant un supplment de vitamine E : 1) l-tocophrol est principalement distribu avec les HDL, 2) l-tocophrol dans les HDL est reconnu par les SR-BI sur la surface des neutrophiles, et 3) le rarrangement du cytosquelette dactine est une tape cruciale pour la prise d-tocophrol par les neutrophiles. (Traduit par Docteur Serge p65 Messier) Introduction Vitamin E is an integral component of all lipid membranes and protects them from attack by reactive oxygen species (ROS) (1,2). Polyunsaturated fatty acids of membranes are vulnerable to attack by ROS, which can initiate a chain reaction of lipid destruction that destroys the membrane of the cell. Vitamin E can quench peroxidation reactions in membranes and is probably the most important PROTAC FLT-3 degrader 1 antioxidant present in cell membranes (3). The newborn dairy calf has minimal reserves of lipid-soluble vitamins and fetal uptake is limited (4,5). Vitamin E supplementation has been shown to have positive effects on the immune system of young dairy calves (6,7). We have reported that providing vitamin E supplementation to newborn calves activates killing ability and intracellular signal transduction, including protein kinase C, intracellular Ca2+, and tyrosine kinase of neutrophils (8). It has been reported that cellular -tocopherol concentrations of red PROTAC FLT-3 degrader 1 blood cells were approximately 5 times higher in vitamin E-supplemented Holstein calves than in control calves (9). However, levels of alpha ()-tocopherol concentration in neutrophils from calves have not yet been examined. The cellular uptake of -tocopherol within high-density lipoprotein (HDL) is reported to be mediated by scavenger receptor class B, type I (SR-BI) (10,11). Moreover, a previous study using SR-BI-deficient mice has shown a deficiency in the uptake of -tocopherol from plasma lipoproteins to specific tissues (12). Rajapaksha et al (13) sequenced the bovine SR-BI and examined changes in expression of messenger ribonucleic acid (mRNA) of SR-BI during development and granulosa cell luteinization Sequencing of the bovine HDL-receptor showed that it codes for a protein of 509 amino acids with close identity to hamster, mouse, rat, and human sequences.