Glutamic Acid Signal Synchronizes Protein Synthesis Kinetics in Hepatocytes from Old Rats for the Following Several Days. Cell Metabolism Memory.

The kinetics of protein synthesis was investigated in primary cultures of hepatocytes from old rats in serum-free medium. The rats were fed mixed fodder supplemented with glutamic acid and then transferred to a regular mixed fodder. The amplitude of protein synthesis rhythm in hepatocytes isolated from these rats increased on average 2-fold in comparison with the rats not receiving glutamic acid supplement.

Glutamic Acid as Enhancer of Protein Synthesis Kinetics in Hepatocytes from Old Rats.

Dense cultures of hepatocytes from old rats (~2 years old, body weight 530-610 g) are different from similar cultures of hepatocytes from young rats by the low amplitude of protein synthesis rhythm. Addition of glutamic acid (0.2, 0.

Glutamic Acid - Amino Acid, Neurotransmitter, and Drug - Is Responsible for Protein Synthesis Rhythm in Hepatocyte Populations in vitro and in vivo.

Primary cultures of rat hepatocytes were studied in serum-free media. Ultradian protein synthesis rhythm was used as a marker of cell synchronization in the population. Addition of glutamic acid (0.

[Blockade of proteasome activity disturbs the rhythm of synthesis of the protein marker of direct cell-cell interactions].

The effect of inhibition of proteasome activity on direct cell-cell interactions in primary hepatocyte cultures was studied. The circahoralian rhythm of protein synthesis was a marker of cell-cell communication. The addition of the proteasome inhibitor MG132 at doses of 10 or 20 μM to the medium with hepatocyte cultures for 19 h resulted in a significant reduction in the total pool of 3H-leucine in cells.

Administration of dopamine to rats disorganizes the rhythm of protein synthesis in hepatocytes.

Dopamine was injected intravenously (9 μg/kg) or intraperitoneally (15 μg/kg) to Wistar rats (3-4 months, 300-400 g). Hepatocytes were isolated 40 min after dopamine injection. Dense cultures were maintained on collagen-coated glasses.

Effect of protein synthesis rhythm-organizing signal persists for a day after single administration of melatonin to rat.

Melatonin administered to rat intraperitoneally organizes ultradian rhythm of protein synthesis in hepatocytes that persists for 1 day after exposure to the synchronizing signal. Hepatocytes were isolated 1 day after melatonin administration and cultured on coverslips in a serum-free medium. In 24 h in culture, the kinetics of protein synthesis was analyzed.

Dopamine disorganizes the rhythm of protein synthesis disrupting self-organization of hepatocytes in vitro.

We studied dense 24-hour cultures of rat hepatocytes in serum-free medium on collagen-coated slides. As before, a circahoralian rhythm of protein synthesis was observed in control cultures in a fresh medium. No rhythm was found after addition of 1-10 μM dopamine to the medium containing such cultures.

[Mesenchymal stromal cells synchronize the rhythm of protein synthesis under the effect of an exogenous signal].

A comparative study was performed of dense 5-hour cultures of rat hepatocytes and equal-density cultures of mesenchymal stromal cells (MSC) isolated from human adipose tissue of rat bone marrow. The cells were grown on collagen-coated class slides in serum-free medium. Unlike in hepatocytes, no rhythm of protein synthesis was initially revealed in MSC, but such a rhythm manifested itself when the culture medium was supplemented with melatonin (2 nM, 5 min).

[Self-synchronization of the protein synthesis rhythm in HaCaT cultures of human keratinocytes].

In cultures of human keratinocytes HaCaT contained in a serum-free medium on glass, a circahoralian rhythm of protein synthesis was found similar to the one in hepatocytes in vitro. The intensity of the synthesis was determined by the inclusion of 3H-leucine corrected for the pool of free marked leucine. Rhythm was studied in washed 1- or 2-day cultures after the change of the medium.

Melatonin as the most effective organizer of the rhythm of protein synthesis in hepatocytes in vitro and in vivo.

Recent data has extended a large array of melatonin functions by the discovery of melatonin's involvement in the organization and regulation of the rhythm of intracellular protein synthesis. An ultradian rhythm in total protein synthesis has been detected in primary hepatocyte cultures 5 min after addition of 1-5 nM melatonin to the medium. The melatonin effect was mediated via its receptors (as shown in experiments with luzindole), leading to the cell synchronization as well as the mean rate of protein synthesis rate being increased.

[Melatonin injected into rat efficiently synchronizes the rhythm of protein synthesis in primary hepatocyte cultures isolated from this rat].

Melatonin injected intraperitoneally into rat synchronizes the ultradian rhythm of protein synthesis after 100 min in primary hepatocyte cultures isolated from this rat, which are studied after 1 or 2 days. The effective synchronization concentrations of melatonin--0.01-0.

[Melatonin promotes and synchronizes protein synthesis in hepatocyte culture from old rats].

The effect of 1 to 1000 nM melatonin was studied on daily cultures of rat hepatocytes on slides in serum-free medium. The minimum melatonin concentration (1 nM) proved to synchronize protein synthesis in asynchronous sparse cultures of hepatocytes from rats of different age, and a circahoralian rhythm of protein synthesis was revealed in them. In dense weekly synchronous hepatocytes from old rats (2.

[Signaling factors of self-organization of protein synthesis rhythm in hepatocyte cultures--gangliosides and catecholamines function independently].

Considering the data on the low level of self-organization (self-synchronization) of protein synthesis rhythm in aging, we studied the possible interference of the signaling factors of self-organization, gangliosides and catecholamines, as well as catecholamine reception. Experiments were carried out on primary cultures of rat hepatocytes on slides. Inhibited ganglioside synthesis did not prevent the organization of protein synthesis rhythm by the alpha-adrenomimetic agent phenylephrine.

Involvement of protein kinases in self-organization of the rhythm of protein synthesis by direct cell-cell communication.

Primary cultures of rat hepatocytes grown on slides were studied in serum-free medium. Ultradian protein synthesis rhythm was used as a marker of synchronization of individual oscillations, resulting in the formation of a common rhythm of the cell population, i.e.

[Mechanism of direct cell interactions. Self-organization of protein synthesis rhythm].

Primary 24-hour cultures of hepatocytes on slides in a serum-free medium were studied. Circahoralian rhythm of protein synthesis served as a marker of cell cooperation. Stimulation of protein kinase activities by phorbol 12-myristate 13-acetate at 0.

[Aftereffect of synchronizers of protein synthesis rhythm in hepatocytes in vitro].

The effect of gangliosides and phenylephrine synchronizing the protein synthesis rhythm was preserved in hepatocytes cultured in the normal serum-free medium for one-two days. Hence, the membrane signal triggers intracellular, as was shown by us earlier, calcium-dependent processes, which regulate the kinetics of protein synthesis for a certain time after the signal perception.

Single short-term signal that enhances cooperative activity of old rat hepatocytes acts for several days.

Primary cultures of rat hepatocytes were studied in serum-free medium. Ultradian protein synthesis rhythm was used as a marker of overall cell synchronization and cooperation amongst the population. The level of synchronization was determined by amplitudes of the rhythm.

[Age-related features of protein synthesis rhythm in hepatocytes. Effects of extracellular medium].

Cell interactions have been studied in cultures pf hepatocytes from young and old rats. The rhythm of protein synthesis is an index of cell interaction and synchronization in culture, while the amplitude of oscillations characterized cell cooperation in an aggregate rhythm. The mean rhythm amplitude in the culture of hepatocytes from old rats is twice lower than that from young rats.

Loss of hepatocyte co-operative activity after inhibition of ganglioside GM1 synthesis and shedding.

Pretreatment of hepatocyte cultures with 1 microM d-l-threo-1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol-HCL (PPPP) for 24 h decreased the ganglioside GM1 content of the cells by approximately 50% and that of the conditioned medium by 90%. No rhythm in the rate of protein synthesis was detected in dense cultures pretreated with PPPP, but was observed in control dense cultures. Conditioned medium from control dense cultures induced synchrony in sparse cultures, which were non-synchronous in their own medium.

Phenotype determination of anti-GM3 positive cells in atherosclerotic lesions of the human aorta. Hypothetical role of ganglioside GM3 in foam cell formation.

Earlier we reported that atherosclerotic plaques contain cells which were specifically and very intensively stained with anti-GM3 antibodies although no GM3 positive cells were detected in the normal non-diseased arterial intima. Because of their lipid inclusions, GM3 positive cells in atherosclerotic lesions seemed to be foam cells but their origin needed clarification. Using an immunohistochemical technique in the present work, we showed that some of these foam cells contained CD68 antigen.

[The adrenoreceptor blocker prazosin does not prevent synchronization of the protein biosynthesis rhythm by exogenous gangliosides in the hepatocyte culture].

We studied the effect of the alpha 1-adrenolytic prazosine on dense cultures of hepatocytes, which are normally characterized by the protein synthesis rhythm, and diluted cultures, in which such a rhythm is revealed after external synchronization. Exogenous gangliosides (a fraction of the total gangliosides of the bovine brain) then synchronize the rhythm in diluted cultures; this effect is also displayed in the presence of 10(-7) M prazosine. The synchronizing effect of the medium conditioned by dense cultures was also preserved in the presence of prazosine.