Protein synthesis is activated in primed neutrophils: a possible role in inflammation

1987 ◽  
Vol 7 (11) ◽  
pp. 881-890 ◽  
Author(s):  
Valerie Hughes ◽  
John M. Humphreys ◽  
Steven W. Edwards

Circulating human neutrophils exhibited low rates of protein biosynthesis, as determined by their ability to incorporate [35S]methionine into TCA-precipitable material. Exposure of cells to the chemotactic peptide (N-formyl-L-methionyl-L-leucyl-L-phenylalanine) increased their rate of protein synthesis, and the maximal stimulation of biosynthesis by this inflammatory agent was observed at 0.1 μM: this concentration of chemotactic peptide “primed” neutrophil activity and only activated the oxidase of these cells by 8% of maximum. The newly-synthesized proteins were analyzed by two-dimensional polyacrylamide gel electrophoresis and compared with those synthesized in control cells. Two classes of proteins were observed in “primed” cells. The first of these comprised proteins whose rate of biosynthesis changed very little upon “priming” whereas the second class comprised proteins whose rate of synthesis increased greatly after exposure to chemotactic peptide. The fMet-Leu-Phe stimulated protein synthesis was inhibited by actinomycin D and cycloheximide showing that this phenomenon required both transcription and translation. We propose that these fMet-Leu-Phe regulated proteins play an important role in the function of neutrophils during an inflammatory response.

1978 ◽  
Vol 170 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Felix H. A. Janszen ◽  
Brian A. Cooke ◽  
Maria J. A. Van Driel ◽  
Henk J. Van Der Molen

The mechanism of action of lutropin on the stimulation of the synthesis of a specific lutropin-induced protein in rat testis Leydig cells was investigated. Lutropin-induced protein has a mol.wt. of approx. 21000 and is detected by labelling the Leydig-cell proteins with [35S]methionine, followed by separation by polyacrylamide-gel electrophoresis and radioautography of the dried gel. The incorporation of35S into lutropin-induced protein was used as an estimate for the synthesis of the protein. Incubation of Leydig cells with dibutyryl cyclic AMP or cholera toxin also resulted in the stimulation of synthesis of the protein. Synthesis of lutropin-induced protein, when maximally stimulated with 100ng of lutropin/ml, could not be stimulated further by addition of dibutyryl cyclic AMP. Addition of 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, further increased synthesis of the protein in the presence of a submaximal dose of lutropin (10ng/ml) but not in the absence of lutropin or with maximal amounts of lutropin (100 and 1000ng/ml). Actinomycin D prevented the effect of lutropin on the stimulation of lutropin-induced protein synthesis when added immediately or 1h after the start of the incubation, but not when added after 5–6h. This is interpreted as reflecting that, after induction of mRNA coding for lutropin-induced protein, lutropin had no influence on the synthesis of the protein in the presence of actinomycin D. Synthesis of the protein was also stimulated in vivo by injection of choriogonadotropin into rats 1 day after hypophysectomy, and the time course of this stimulation of lutropin-induced protein synthesis in vivo was similar to that obtained by incubating Leydig cells in vitro with lutropin. From these results it is concluded that stimulation of lutropin-induced protein synthesis by lutropin is most probably mediated by cyclic AMP and involves synthesis of mRNA.


1979 ◽  
Vol 182 (3) ◽  
pp. 717-725 ◽  
Author(s):  
Alice Dazord ◽  
Dominique Gallet ◽  
Helene Cohen ◽  
Jose M. Saez

The mechanism of corticotropin stimulation of the synthesis of a specific rat adrenal cytosolic protein was investigated. This protein (protein E) has a mol.wt. of approx. 30000. It is detected by polyacrylamide-gel electrophoresis of cytosol prepared from adrenal slices from rats treated with corticotropin in vivo and control rats, the slices being incubated with [3H]- and [14C]-leucine respectively. In rats 1–15 days after hypophysectomy, corticotropin, like dibutyryl cyclic AMP, induces an increase in protein E similar to that induced in control rats, even though both compounds no longer stimulate total protein synthesis. Corticotropin stimulation of protein E synthesis is mediated by cyclic AMP but not by corticosterone, since aminoglutethimide, a steroidogenic inhibitor, does not affect corticotropin stimulation, and dexamethasone alone has no effect. Actinomycin D, when injected in vivo 1h before or after corticotropin injection, prevents the effect of corticotropin on protein E synthesis, which is interpreted as evidence that mRNA synthesis is necessary for the stimulation of protein E synthesis. When injected more than 2h after corticotropin, actinomycin D does not prevent corticotropin stimulation of protein E synthesis, but completely blocks corticotropin stimulation of total protein synthesis. This is interpreted as meaning that, after stimulation of mRNA coding for protein E, corticotropin has no effect on the synthesis of protein E. On the other hand, corticotropin stimulation of protein E synthesis persists after hypophysectomy even though it no longer stimulates total protein synthesis. These data suggest that the factor(s) involved in the synthesis of protein E are more stable than those involved in total protein synthesis.


1984 ◽  
Vol 107 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Stephen F. Kemp ◽  
Murry Mutchnick ◽  
Raymond L. Hintz

Abstract. Somatomedin C (SM-C), insulin, and triiodothyronine (T3) each result in a 2-fold stimulation of incorporation of [125I]leucine into protein by cultured chick sternal chondrocytes. Maximal stimulation occurred at concentrations of 12.5 × 10−9 m SM-C, 11 × 10−9 m insulin, and 1.5 × 10−9 m T3. Submaximal concentrations of SM-C and T3 were additive in their effect, and together stimulated [125I]leucine incorporated to a level greater than that achieved by either alone. Submaximal concentrations of SM-C and insulin were also additive in their stimulatory effect, but only to the level achieved by either alone. It was possible to demonstrate specific binding of [14C]SM-C to chondrocytes, and bound SM-C could be displaced by either unlabelled SM-C or insulin at concentrations similar to concentrations that stimulated protein synthesis. Actinomycin D abolished stimulation by T3, but not by insulin or SM-C. Thus, it appears that SM-C and insulin increase protein synthesis by stimlating the translational process after binding to the same receptor. T3 appears to act through a different mechanism, which requires stimulation of transcription.


1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.


1974 ◽  
Vol 140 (3) ◽  
pp. 549-556 ◽  
Author(s):  
R. L. Boeckx ◽  
K. Dakshinamurti

The effect of administration of biotin to biotin-deficient rats on protein biosynthesis was studied. Biotin treatment resulted in stimulation by more than twofold of amino acid incorporation into protein, both in vivo and in vitro in rat liver, pancreas, intestinal mucosa and skin. Analysis of the products of amino acid incorporation into liver proteins in vivo and in vitro indicated that the synthesis of some proteins was stimulated more than twofold, but others were not stimulated at all. This indicates a specificity in the stimulation of protein synthesis mediated by biotin.


1988 ◽  
Vol 252 (1) ◽  
pp. 143-149 ◽  
Author(s):  
A K Campbell ◽  
A K Patel ◽  
Z S Razavi ◽  
F McCapra

1. A method has been developed to incorporate the apoprotein of the Ca2+-activated photoprotein obelin, and mRNA purified from the hydroid Obelia, into the cytoplasm of intact human neutrophils. This was based on internal release from pH-sensitive immunoliposomes taken up initially by phagocytosis. 2. Addition of the prosthetic group of obelin, coelenterazine, to these cells containing apo-obelin or Obelia mRNA resulted in formation of active Ca2+-activated obelin. 3. The obelin formed within the neutrophils responded to the chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (1 microM) and to the membrane attack complex of complement (C5B6789n). 4. The formation of the apo-obelin from mRNA within neutrophils was inhibited by over 80% in the absence of added amino acids, and by over 90% by the protein-synthesis inhibitor puromycin (100 micrograms/ml). 5. The translation of Obelia mRNA inside cells provides a method for circumventing consumption of Ca2+-activated photoproteins during cell activation or injury, and for monitoring protein synthesis in living cells.


1972 ◽  
Vol 54 (3) ◽  
pp. 483-492 ◽  
Author(s):  
N. T. DAVIES ◽  
K. A. MUNDAY ◽  
B. J. PARSONS

SUMMARY A study was made of the effects of cyclic AMP, theophylline, cycloheximide, puromycin and actinomycin D on the stimulation by angiotensin of fluid transport by sacs of rat colon mucosa. Cyclic AMP and theophylline, added together or separately, had no effect on fluid transport by colon sacs, suggesting that the stimulation of fluid transport after the application of angiotensin is not mediated through cyclic AMP. Cycloheximide and puromycin (used at concentrations which block colon protein synthesis by 50–90%) had no effect on fluid transport by control colon sacs, but completely blocked the stimulatory response of the colon to angiotensin. In contrast, actinomycin D (at a concentration which significantly inhibits RNA synthesis) did not affect fluid transport in control or angiotensin-stimulated colon sacs. The results are discussed in relation to the possibility that protein synthesis, at the stage of translation, is involved in the action of angiotensin on fluid transport by the colon.


1992 ◽  
Vol 262 (5) ◽  
pp. E627-E630 ◽  
Author(s):  
B. J. Peters ◽  
J. A. Rillema

These studies were carried out to explore the possible effect of prolactin (PRL) on glucose uptake into culture mammary gland explants derived from 12- to 14-day pregnant mice. PRL was found to stimulate an increased rate of uptake of a nonmetabolized glucose analogue, 2-[3H]deoxyglucose, into cultured mammary tissues. The onset of this response was 16 h after the addition of PRL, and the response persisted for at least 24 h. A similar temporal response was observed when the PRL stimulation of [14C]glucose oxidation to 14CO2 was determined. The lowest PRL concentration that elicited a stimulation of 2-deoxyglucose uptake was 20 ng/ml, and a maximum response occurred with PRL at a concentration of 250 ng/ml. Ongoing protein synthesis appears to be essential for PRL to express its effect on 2-deoxyglucose transport since cyclohexamide, puromycin, and actinomycin D abolished the PRL response. It is also apparent that the PRL stimulation of 2-deoxyglucose involves activation of a specific carrier-mediated uptake transport system, since the rate of uptake of L-glucose into mouse mammary gland explants was unaffected by PRL.


1993 ◽  
Vol 265 (2) ◽  
pp. H666-H674 ◽  
Author(s):  
C. T. Ivester ◽  
R. L. Kent ◽  
H. Tagawa ◽  
H. Tsutsui ◽  
T. Imamura ◽  
...  

Cardiocytes were induced to contract via electrical field stimulation with an 8 V/cm electrical square-wave pulse of 5 ms at 0.125-2.0 Hz for up to 6 h. Protein synthesis rates were measured as rate of incorporation of [3H]-phenylalanine into total cell protein. Rates of protein synthesis were accelerated 43 +/- 4%, P < 0.001, by 4 h. The acceleration of total protein synthesis showed a frequency dependence between 0.125 and 0.5 Hz. In addition to accelerating rates of total protein synthesis, electrical stimulation of contraction accelerated fractional rates of synthesis of myosin heavy chain by 42 +/- 8%, P < 0.05. Protein synthesis rates were not accelerated upon electrical stimulation using subthreshold voltages. Addition of 100 ng/ml of actinomycin D had no effect on the ability of electrical stimulation of contraction to accelerate protein synthesis. To uncouple excitation-contraction coupling, 2,3-butanedione monoxime (BDM) was used to block actin-myosin cross-bridge interactions. BDM significantly decreased the ability of electrical stimulation to accelerate protein synthesis rates.


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