A comparative analysis of the morphochemical changes in the neurons of the visual and sensorimotor cortices and the nucleus accumbens of rats administered tuftsin

White rats were treated with a single administration of tetrapeptide tuftsin (Thr-Lys-Pro-Arg) in the dose 300 mcg/kg (b.w). Using interferometry, the protein content and concentration were assessed 15, 30 and 60 minutes after injection. The area of the neuron cytoplasm and nucleus were measured too. The nucleoplasmic balance and dispersion were calculated. Significant alterations in the protein contents and cellular area, nucleoplasmic balance and dispersion were detected in neurons of visual, sensomotor cortex and of n. accumbens. A possible interrelation is discussed between tuftsin action and the functional activity of neurons, between the level of their protein metabolism and establishment of emotional and motor response.     

Interaction on the antinociceptive effect between neurotensin and enkephalins or tuftsin

The aim of this paper was to study the interaction between neurotensin and both enkephalins or its synthetic analogue D-Ala2-metenkephalinamide, or tuftsin, on the antinonciceptive effect of these peptides in mice after intracisternal injection. Antinociception was measured by the hot-plate method. It was shown that neurotensin antagonized evidently the antinociceptive effect of enkephalins and their analogue. On the contrary, neurotensin and tuftsin were agonists in induction of analgesia. It is concluded that neurotensin modulates in an opposite way the function of the enkephalinergic neurons and the central action of tuftsin.     

The immunomodulatory effects of tuftsin on the non-specific immune system of Indian Major carp, Labeo rohita

The purpose of this study was to determine if injections of different dosages of tuftsin would enhance the immune response and disease resistance against the infections due to the opportunistic pathogens Aeromonas hydrophila and Edwardsiella tarda in Labeo rohita fingerlings. Hence, four different dosages of tuftsin in PBS suspension at the rate of 0, 5, 10, 15 mg kg(-1) body weight of fish were injected intraperitoneally to the fingerlings of L. rohita at 2-week intervals for four times. After every 2-week interval, different serum biochemical, haematological and immunological parameters of fish were evaluated. Biochemical and haematological parameters including serum total protein content, albumin content, globulin content, albulin:globulin ratio, glucose content, leucocyte counts etc.; cellular immune parameters including superoxide anion production, phagocytic activities, lymphokine production index etc.; humoral immune parameters including lysozyme activity, complement activity, serum bactericidal activity etc., in the fish were evaluated after every 2-week interval. After 56 days, fish were divided into two subgroups under each major treatment group for challenge with two pathogens A. hydrophila and E. tarda. The mortality (%) and agglutinating antibody titre was recorded on 28th day post challenge. Most of the immune parameters including leucocyte count, phagocytic ratio, phagocytic index, lysozyme activity, complement activity, and serum bactericidal activity were significantly (p相似文献   

Effect of tuftsin, a neuropeptide and its derivatives on the content of nicotinamide coenzymes and the activity of cytochrome- c-oxidase of brain tissue

Tuftsin, a neuropeptide, and its derivatives are studied for their influence on the content of oxidized and reduced forms of nicotinamide enzymes as well as on the activity of cytochrome-c-oxidase of the cortex and limbic system. Peptides under study are shown to increase the content of nicotinamide coenzymes, mainly due to the oxidized forms of NAD and enhance the activity of cytochrome-c-oxidase as well mainly in the emotiogenic brain structures. Under these conditions tuftsin and its derivatives intensify cellular respiration of the neurons.     

Positive correlation between superoxide release and intracellular adenosine deaminase activity during macrophage membrane perturbation regardless of nature or magnitude of stimulus

Summary Tuftsin stimulates macrophages to release superoxide in direct proportion to intracellular adenosine deaminase activity over a concentration range of 125 to 625 nM tuftsin. This relation is comparable to that previously observed for stimulation by single concentration of several agents. This finding led to the conclusion that the relation between superoxide and adenosine deaminase is independent of the nature or magnitude of the stimulus. In absolute terms, tuftsin increases superoxide secretion up to 375 nM tuftsin; further increases in tuftsin concentration cause a rapid decrease in superoxide secretion to near base line at 500 nM tuftsin. In contrast, the phagocytic response to tuftsin remains maximal up to 10 M with no indication of inhibition at higher concentrations. Thus, tuftsin stimulation of phagocytosis and superoxide release may be at least partially independent phenomena.     

Proteolysis of human C-reactive protein produces peptides with potent immunomodulating activity

We have studied the ability of human C-reactive protein to modulate the immune response in vitro. Whereas native C-reactive protein did not induce phagocytic leukocytes to chemotax or to produce superoxide, treatment of purified C-reactive protein with human neutrophil-derived acid proteases produced substances with potent effects on leukocyte function. Close examination of the primary structure of human C-reactive protein revealed three regions evenly distributed throughout the protein each of which contain peptide sequences closely resembling the amino acid sequence of the immunomodulator peptide tuftsin, Thr-Lys-Pro-Arg. We have synthesized the three peptides which include Thr-Lys-Pro-Leu ([Leu4]tuftsin), Gly-Lys-Pro-Arg ([Gly1]tuftsin), and Thr-Lys-Pro-Gln ([Gln4]tuftsin) and assayed them for biological activity. The three synthetic peptides were found to stimulate phagocytic leukocytes to chemotax, produce superoxide, and induce mononuclear cells to produce interleukin 1 in vitro at concentrations similar to those concentrations required for tuftsin to induce these phenomena. These results support a potentially important role for C-reactive protein as a possible immunomodulator during inflammation.     

Non-histone chromatin proteins during various stages of activity of immunocompetent cells

Summary Some of the properties of the tetrapeptide tuftsin, Thr-Lys-Pro-Arg, are discussed. We describe three phases of tuftsin activation of the macrophage. Tuftsinyltuftsin, the octapeptide Thr-Lys-Pro-Arg-Thr-LysPro-Arg, was synthesized with a view of minimizing the formation of Lys-Pro-Arg, from tuftsin by tissue aminopeptidases. The tripeptide is a tuftsin inhibitor. The octapeptide proved to be quite effective in prolonging the life of syngeneic mice injected with L1210 leukemia cells. Its effect in our laboratory, was considerably better than we could obtain with tuftsin. A simple method for purifying tuftsin by high performance liquid chromatography is described using 0.75% trifluoroacetic acid in water.The tuftsin sequence Thr-Lys-Pro-Arg is present in P 12 protein of Rausher murine leukemia virus. A close analog Thr-Arg-Pro-Lys appears in yet another virus protein the haemagglutinin of influenza virus. A second close analog Thr-Arg-Pro-Arg forms the penultimate carboxyterminal of a pancreatic polypeptide found in human and several animals.     

Peptide fragments from the tuftsin containing domain of immunoglobulin G synthesis and biological activity

Peptides corresponding to sequences of the Fc-portion of immunoglobulin G (IgG) surrounding and containing the tuftsin molecule were synthesized. The compounds were assayed for their ability to compete with [3H-Arg4]tuftsin in binding to mouse peritoneal macrophages and to stimulate the cell's capacity to phagocytize. Despite the sensitivity that tuftsin has demonstrated to various chemical modifications and structural alterations which usually cause reduction or total loss of biological activity, IgG-related analogs possess potent tuftsin-like activity. The activity is not caused by enzymatic breakdown and release of tuftsin. The fact that the elongated tuftsin analogs can specifically be attached to and activate macrophages may indicate a possible connection between Fc and tuftsin's receptors.     

Synthetic peptides from C-reactive protein containing tuftsin-related sequences

Peptides containing Lys-Pro-Arg or Thr-Lys-Arg segments corresponding to various regions of human C-reactive protein were synthesized. The peptides prepared were composed of amino acid residues, 37–58, 51–58, 173–187 and 181–187 of C-reactive protein. The relationship between C-reactive protein, its synthetic fragments and tuftsin (Thr-Lys-Pro-Arg) was investigated in binding studies, enhancement of phagocytosis and change in cyclic nucleotide levels of mouse macrophages. The peptides AA 51–58 and 181–187 did enhance macrophage phagocytosis capacity to a similar extent to that of tuftsin. They showed however only negligible binding to the cells. The effect of C-reactive protein and the synthetic peptides on metabolic activity of neutrophils was also investigated. It was shown that the peptides inhibited to some degree superoxide production, lysozyme release and Vitamin B₁₂ binding protein release from neutrophils in the absence and presence of the stimulants, PMA or Con A. Comparable activity with tuftsin was not found.     

A cytochemical study of the effect of tuftsin on the enzyme activity in functionally different formations of the brain in rats]

Quantitative cytochemical methods in functionally different rat brain formations (sensomotor cortex, visual cortex, nucleus caudatus, hippocampus) showed the peculiarities of the effect of tuftsin on the activity of some enzymes (the oxidative, neurotransmitter and protein metabolism enzymes) 15 min and 3 days after its single administration. No changes of activity of neurotransmitter metabolism enzymes (monoamine oxidase, acetylcholinesterase) were registered cytochemically. The specificity of the neuro-tropical effect of tuftsin on protein (activity of aminopeptidase and acid phosphatase) and oxidative (activity of glutamate dehydrogenase and glucose-6-phosphate dehydrogenase) metabolism in different functional brain systems is discussed.     

Expression of the gene for hybrid beta-lactamase pBR322 with C-terminal fragment containing tuftsin (Thr-Lys-Pro-Arg)

A hybrid beta-lactamase gene with a synthetic tuftsin-coding DNA fragment inserted at the Pst I-site of pBR322 plasmid has been obtained and its expression has been studied. Radioactive amino acids have been used to show that in E. coli chi 925 minicells up to 30% of newly synthesized chimeric protein is secreted into periplasm providing the tuftsin transport. After hybrid protein cleavage with CNBr, tuftsin has been isolated using ion-exchange and thin-layer chromatography.     

Effect of tuftsin on the leucyl aminopeptidase activity of the subcellular components in cerebral cortical formations

The administration of a tetrapeptide tuftsin in a dose of 300 mkg/kg body weight for 15, 75 minutes leads to the change in specific activity of leucyl-arylamidase in subcellular component and their membrane which has been isolated from the rabbit sensomotor cortex and visual cortex. Reaction of a tetrapeptide depends on time. It is strongly pronounced in sensomotor cortex and has an advantage in synaptosomes and their membrane. Possibility of tuftsin in protein exchange of cellular and subcellular component is discussed.     

Immunocytochemical Quantification of Tyrosine Hydroxylase at a Cellular Level in the Mesencephalon of Control Subjects and Patients with Parkinson's and Alzheimer's Disease

Abstract: Parkinson's disease is characterized by massive degeneration of the melanized dopaminergic neurons in the substantia nigra. The functional capacity of the surviving nigral neurons is affected, as indicated by the subnormal levels of tyrosine hydroxylase (TH) mRNA in these neurons and the presence in the parkinsonian mesencephalon of melanized neurons lacking TH immunoreactivity. This is apparently in contradiction with the known overactivity of dopamine synthesis and release that occurs in the remaining dopaminergic terminals. To test the ability of the surviving neurons to express TH protein, a semiquantitative immunocytochemical method was developed. The relative amounts of TH were estimated with a computer-assisted image analysis system in the dopaminergic neurons of representative mesencephalic sections of control and parkinsonian brains and for comparison in brains from patients with Alzheimer's disease. In control brains, the mean TH content per neuron differed from one subject to another and between the different dopaminergic cell groups of the mesencephalon in the same subject. Within a given dopaminergic region, the level of TH was variable among neurons. In patients with Parkinson's disease, the ratio of TH protein content per neuron in the substantia nigra by reference to that of the central gray substance was reduced. In patients with Alzheimer's disease, the amount of TH was selectively reduced in the remaining dopaminergic neurons of the ventral tegmental area, a region characterized by a loss in dopaminergic neurons. The decrease in cellular TH content might therefore be related to the presence of the neurodegenerative process in the area considered. In patients with Parkinson's disease, the incapacity of the surviving neurons to express normal TH levels may reduce the efficiency of the hyperactivity mechanisms that develop in the remaining striatal dopaminergic terminals.     

Comparison of the neuro- and immunomodulator properties of low-molecular neuropeptides

A study was made of the effect of the low-molecular neuropeptides, leu- and met-enkephalins, thyroliberin (TRH), the C-end tripeptides, gastrin (MAF) and oxytocin (MIF) on the content of biogenic monoamines and their metabolites and on the production of humoral antibodies to sheep red blood cells. The action of the peptides enumerated was compared to that of the peptide immunostimulant, tuftsin. All the peptides (upon intraventricular administration) with the exception of tuftsin affect the content of brain biogenic monoamines or their metabolites. Moreover, upon intravenous injection the neuropeptides under study except met-enkephalin exert a modulating action on the immune response pattern and intensity Leu-enkephalin, MIF and MAF have immunostimulant activity similar to tuftsin. TRH given in high doses (100 and 150 mg/kg) provokes almost a two-fold decrease in the antibody titer. This peptide has an immunosuppressant effect when administered both intravenously and intracisternally. It is suggested that neuro- and immunomodulator effects have much in common at the level of cell receptors.     

Total protein content and concentration in the neurons of the "mirror" epileptiform focus in the rat brain at the late stages of its existence]

The experimental lesion in rat brain was produced by the implantation of cobaltogelatin rod into the right parietalis anterior area. A quantitative measurement of total protein was made by microdensitometer in neurons controlateral to cobalt lesion at 112-115 days after cobalt implantation. In the experimental animals, protein content decreased in neurons of lamina III and V area parietalis anterior and the nucleus lateralis thalami by 6, 60 and 53%, resp. It has been concluded that different type neurons have different protein changes in response to paroxyzmal activity at late stages of epileptogenic mirror focus.     

Effect of early photic deafferentation on the neuronal development of the parietal area of the rabbit cerebral cortex]

It has been shown interferometrically that the neurons of laminae III-V of the parietal area in the cortex of visual deprivated rabbits manifest features of morphochemical underdevelopment (decrease in size and protein content in the neurons) in comparision with the normal ones. These changes resemble those in the visual area, but are less pronounced being definitely specific for each lamina. The reaction of the neurons of the cortex parietal area of rodents on the light deafferentation is discussed.     

Tuftsin,Thr-Lys-Pro-Arg

Summary Tuftsin, a natural occurring tetrapeptide, has been found to exhibit several biological activities connected with immune system function. Although little is known about tuftsin's biogenesis, much information has been gleaned about its structure-function relationships, which have shown that several features of the molecule are essential for expression of full biological activity. Furthermore, specific receptor sites for tuftsin have been found to exist exclusively on phagocytic cells. Research indicates that tuftsin binding to target cells effect intracellular calcium and cyclic nucleotide levels. Implication of these facts on tuftsin's mode of action are discussed.Basic peptidic segments resembling tuftsin are found in a variety of regulatory peptides. Questions are, therefore, raised as to the biospecificity and cross-reactivity of these sequences. Substance P, one such peptide, which binds with and activates tuftsin receptors, is described.In light of tuftsin's therapeutic potential, assays for its determination have been introduced. When applied to analyze human blood serum of normal as well as of various pathological origins, direct correlation was found between tuftsin levels and susceptibility to bacterial infections.     

The phagocytosis stimulating peptide tuftsin: Further look into structure-function relationships

Summary Sixteen new analogs of the phagocytosis-stimulating peptide tuftsin have been synthesized. The biological activities of these synthetic peptides, in which either the C-terminal or both C- and N-terminals are chemically altered, were evaluated by studying their effects on the phagocytosis of heat-killed yeasts and on the reduction of the dye nitroblue tetrazolium by normal human polymorphonuclear leukocytes. The results demonstrate that the integrity of the guanidine side chain of arginine at position four of tuftsin is crucial for maximal activity. Modification, even in side chain length, of the guanidine leads to decreasing activity. Preservation of the positive charge of position four of tuftsin yields analogs possessing considerable activity. Simultaneous alterations of both C- and N-terminal results in diminishing activites. The results of this study are discussed in relation to the structural features of tuftsin. It appears that interaction between the carboxyl of Arg⁴ and the amino group of Thr¹ which would indicate a specific conformation such as a 4 1 -turn are not favored.     

Tuftsin and some analogs: synthesis and interaction with human polymorphonuclear leukocytes

The phagocytosis-stimulating tetrapeptide tuftsin, L-threonyl-L-lysyl-L-prolyl-L-arginine, was synthesized by both conventional and polymeric-reagent approaches. Using a combination of the two methods several analogs were prepared, including: [Ala1]tuftsin, [Lys1]tuftsin, [Ser1]tuftsin, [Val1]tuftsin, acetyl-tuftsin, p-aminophenylacetyl-tuftsin and tyrosyl-tuftsin. [Des-Thr1]tuftsin and [omega-NO2(4)]tuftsin were synthesized using a conventional procedure. The effects of synthetic peptides on the phagocytosis of heat-killed yeasts and on the reduction of the dye nitroblue tetrazolium by normal human polymorphonuclear leukocytes were investigated. Tuftsin and to a lesser extent [Lys1]tuftsin and [Ser1]tuftsin were found to stimulate phagocytosis, whereas the other analogs synthesized as well as [Ser1]tuftsin exhibited inhibitory effects to tuftsin's action. Tuftsin alone has stimulated nitroblue tetrazolium reduction; [Des-Thr1]tuftsin and [Ala1]tuftsin repressed this stimulation, while the other peptides showed no effect.