Biochemistry (Moscow), Supplement Series A: Membrane and Cell Biology最新文献

Anticancer peptides are of interest for cancer treatment. Nowadays, the process of apoptosis is considered a molecular target for cancer therapy. In the present study, the toxic effect of the HL-7 peptide on cervical cancer cells HeLa was investigated using the MTT assay. Also, the expression levels of Bax, Bcl-2, p53, caspase-3, PTEN, and Akt genes in HeLa cells treated with HL-7 were assessed by real-time PCR. Besides, the percentage of cells in early and late stages of apoptosis was determined using flow cytometry. The obtained results indicated that the peptide HL-7 inhibited growth of HeLa cells with IC₅₀ of 31 μM. The expression levels of Bax, p53, caspase-3, and PTEN genes were increased in HeLa cells treated with the HL-7 peptide as compared to untreated HeLa cells, while the expression levels of Bcl-2 and Akt genes was decreased (p < 0.05). The results of flow cytometry analysis indicated a high percentage of cells in the late apoptosis stage (p < 0.05). Our findings suggest that peptide HL-7 can be involved in inducing the mitochondria-dependent apoptosis pathway. However, additional studies are needed to elucidate the exact mechanism of action of the peptide on HeLa cancer cells and the prospects for its therapeutic use in the clinic.

It is known that activated derivatives of long-chain fatty acids acylcarnitines (LCAC) are considered the most toxic, which, along with calcium, can participate in the induction of the mitochondrial pore, involving various types of phospholipases. In this study, the effect of inhibitors of Ca²⁺-independent and Ca²⁺-dependent phospholipases, as well as an inhibitor of carnitine palmitoyltransferase on the induction of pores with D,L-palmitoylcarnitine (PC, C16:0) was investigated. In experiments on isolated rat liver mitochondria, the effect of PC on mitochondrial respiration rate, membrane potential (ΔΨm) and mitochondrial swelling during oxidation of glutamate and pyruvate or succinate was studied. It was shown that inhibitors of carnitine palmitoyltransferase-1 etomoxir 2, Ca²⁺-dependent phospholipase cPLA2 aristolochic acid or Ca²⁺-independent phospholipase iPLA2γ bromoenol lactone and PACOCF3 caused an increase in critical concentrations of D,L-palmitoylcarnitine (PC*), which were required to decrease the membrane potential and induce mitochondrial swelling. In the ADP activated state 3 (ADP + Mg²⁺ + hexokinase), Ethomoxir 2 and aristolochic acid promoted the inhibition of respiration and dissipation of membrane potential caused by excess of PC, while phospholipase inhibitors iPLA2γ PACOCF3 and bromoenol lactone provided a pronounced protective effect. Inhibition of iPLA2γ prevented the decrease of ΔΨm and inhibition of respiration caused by PC. Thus, the results obtained indicated the involvement of mitochondrial phospholipase iPLA2γ in the induction of the mitochondrial pore by long-chain acylcarnitines.

In the aging and the development of age-associated diseases, the trigger mechanism is the hyperactivation of the hypothalamic-pituitary-adrenal neuroendocrine axis, hypersecretion of glucocorticoids, which, under excessive and long-term stimulation, have inflammatory and degenerative effects. Chronic stress exacerbates glucocorticoid-dependent atrophic changes in the aging brain, increases neuroinflammation and neurological dysfunction, and is a key risk factor for Alzheimer’s disease. In the correction of aseptic neuroinflammation in elderly and senile patients, the use of anti-inflammatory agents that exhibit anti-glucocorticoid (pro-anabolic) and anti-glutamate (anti-excitotoxic) effects is pathogenetically justified. Succinate/SUCNR1 signalling is involved in the development of immunomodulatory, trophic, and anti-hypoxic effects; however, its role in the mechanisms of stress response remains unexplored. The aim of this study was to assay the impact of succinate/SUCNR1 signalling on the development of stress-induced neuroinflammation in the cerebral cortex of old rats. The work was performed on outbred albino male rats aged 18 months. Chronic restraint stress was modelled by immobilizing animals in individual plastic cases for 6 h daily for 5 days. Mexidol (2-ethyl-6-methyl-3-hydroxypyridine (EMHP) succinate) was used as a form of succinate that crosses the blood-brain barrier. Mexidol was administered intraperitoneally to old rats at a dose of 100 mg/kg daily for 5 days 15 min before the onset of stress. The levels of proinflammatory cytokines (IL-1β, TNF-α), anti-inflammatory cytokines (TGF-β1, IL-10), glucocorticoid receptors (GRα), transcriptional coactivator PGC-1α, succinate receptor SUCNR1/GPR91, and vascular endothelial growth factor (VEGF) were determined by immunoblotting in cerebral cortex (CC) samples. It was shown that chronic immobilization stress caused an increase in the level of IL-1β and TNF-α during stress, which was accompanied by a decrease in the content of anti-inflammatory cytokines, SUCNR1, GRα, PGC-1α. The course administration of EMHP succinate limited the development of stress-induced neuroinflammation in the CC of old rats and prevented a decrease in the levels of SUCNR1, IL-10, TGF-β1, PGC-1α, and GRα. The study reveals for the first time the stress-protective potential of succinate/SUCNR1 signalling in the brain of old rats associated with the activation of PGC-1α-dependent anti-inflammatory mechanisms under conditions of chronic stress.

Gamma-aminobutyric acid (GABA) is commonly considered as a signaling molecule in the synapses of the central nervous system, where it plays the role of the main inhibitory neurotransmitter in the mature brain and participates in the process of neurogenesis. Recently, data have been obtained indicating that GABA may also be involved in the early stages of skeletal muscle tissue development. In the present study, performed on rat myocyte culture, the effect of exogenous GABA on the process of fusion of myocytes into myotubes was investigated by analyzing such a morphometric indicator as the “fusion index”. The addition of the amino acid to the culture led to a significant concentration-dependent inhibition (up to a complete cessation) of the formation of myotubes. GABA_A receptors and GABA transporters (GAT-2) were considered among possible proteins capable of mediating the effect of amino acids. Evidence of the presence of these proteins on cultured cells was obtained using immunohistochemical methods. The blockade of GABA receptors by gabazine did not affect the fusion index in any way, and GABA continued to exert inhibitory effect in its presence. Inhibition of GABA transporters by nipecotic acid reduced the myocyte fusion index; however, the GABA effect was no longer present under the action of the transporter blocker. The data obtained are consistent with the hypothesis about the participation of the amino acid GABA at the early stages of skeletal muscle development; it suggests that the inhibitory effect of the exogenous amino acid may be due to an increase in its concentration in the sarcoplasm, since both the addition of a GABA transporter blocker and an increase in the extracellular concentration of GABA negatively affect the formation of myotubes.

Neurodegeneration is a complex progressive pathological process leading to the neuronal death, which is induced by various external and internal factors. Neurodegenerative diseases, injuries of the central and peripheral nervous system, mental disorders, and a number of other pathological conditions, accompanied by functional and structural degradation of neurons and their death, is a serious problem in the global healthcare system, as due to these diseases millions of people around the world become disabled or die every year. The situation is complicated by the lack of selective, clinically effective neuroprotective drugs. It has been shown that nitric oxide (NO) and hydrogen sulfide (H₂S) are actively involved in neurodegeneration and cell death of neurons and glia, but their role is not completely clear. This review considers NO- and H₂S-dependent signaling mechanisms underlying the pathogenesis of neurodegenerative processes. The prospects for further studies of the role of NO and H₂S in the nervous tissue under conditions of pathological conditions associated with neurodegeneration are considered.

The spectral characteristics of plant surface cells of different evolutionary levels, from unicellular (diatom algae and spores of horsetails and ferns) to multicellular (woody and herbaceous species) organisms, have been studied. It was shown that the surface layers of the cuticle and cell wall of some analyzed plants included antioxidants – blue pigments azulenes. Using histochemical methods, it has been discovered that here neurotransmitter compounds (biogenic amines) are present in the excretions on the entire surface or are released from specialized secretory structures of leaves. Under conditions of high salt concentration, dopamine and histamine are secreted, which is blocked by the addition of exogenous azulene and proazulene grosshemine. We suggest that the azulene-containing surface protects from the formed reactive oxygen species and toxic biogenic amines in high concentrations.

The effect of recombinant human chorionic gonadotropin (hCG) at pregnancy-appropriate concentrations (10 and 100 IU/mL) on differentiation and functional activity of myeloid-derived suppressor cells (MDSCs) was studied. The object of the study was isolated CD11b⁺ cells that were converted to the MDSC phenotype by two-step activation with GM-CSF cytokines, IL1β and lipopolysaccharide (LPS). After a week of cultivation, the total MDSC level was determined considering the subpopulations M-MDSC and PMN-MDSC, the expression of arginase-1 (Arg1) and indoleamn-2,3-dioxydiogenase (IDO) in these cells, as well as the cytokine profile in cell culture supernatant. It was shown that hCG increased the total number of MDSCs, and its lower concentration (10 IU/mL) contributed to the differentiation of the M-MDSC subpopulation. hCG did not affect the expression of IDO expression in MDSCs, but there was a tendency to increase IDO expression under the influence of hCG at a concentration of 10 IU/mL. CD11b⁺ cells converted to the MDSC phenotype had a low Arg 1 content, making it impossible to evaluate the effect of the hormone on the expression of this enzyme. Evaluation of the cytokine profile by multiplex analysis showed that hCG did not modulate cytokine production in the culture of CD11b⁺ cells converted the MDSC phenotype. This is the first time that hCG has been shown to induce differentiation of MDSCs.

ABCG2 protein (breast cancer resistance protein, BCRP) is an efflux transmembrane protein involved in the transport of endogenous and exogenous substances, as well as in the development of tumor resistance to chemotherapy. In this work, the effects of sex hormones progesterone, estradiol, and testosterone on the relative content of ABCG2 in Caco-2 cells was evaluated. The role of orphan receptors (farnasoid X receptor (FXR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), and liver X receptor subtype alpha (LXRα) in the effects of sex hormones was also studied. The content of ABCG2 was estimated by the Western blot technique. Hormones were used at concentrations of 1, 10, and 100 μM; exposure duration was 24 h. All hormones at all concentrations caused an increase in the content of ABCG2. Inhibition of PXR and FXR prevented an increase in ABCG2 levels induced by progesterone. Suppression of CAR and PXR partially reduced the expression of ABCG2 caused by estradiol, as compared to exposure to estrogen alone, but still the level of the transporter exceeded the control. Inhibition of PXR and FXR attenuated the inducing effect of testosterone; however, the level of the transporter exceeded the control. Thus, it was shown that all sex hormones at concentrations 1, 10, and 100 μM increased the content of ABCG2. CAR and PXR participated in the action of estradiol, while FXR and PXR participated in the action of testosterone and progesterone.

In this study we investigated the role of voltage dependent (K_V), Ca²⁺-activated (K_Ca), and inward rectifier (K_ir) potassium channels in the effects of hydrogen sulfide donor (H₂S) sodium hydrosulfide (NaHS) on spontaneous contractile activity of rat jejunum. It was shown that NaHS dose-dependently (10–500 μM) reduced the tonus of the preparation, as well as the amplitude and frequency of spontaneous contractions of jejunum preparations under isometric conditions; the half-maximal effective concentration (EC₅₀) of the inhibitory effect of NaHS on the amplitude of contractions was 165 μM. The blocker of K_V channels 4-AP (200 μM) caused an increase in the amplitude of spontaneous contractions. NaHS (200 μM) decreased the amplitude and frequency of spontaneous activity of the preparation in the presence of 4-AP as well as in the control, and the effect on basal tonus was less pronounced. Blockers of large conductance K_Ca channels (BK), non-specific TEA (3 mM) and specific paxillin (1 μM), increased the amplitude of spontaneous contractions, while the depressing effect of NaHS was completely preserved. The selective blocker of small conductance K_Ca channels (SK) NS8593 (4 μM) did not affect the tonus of the preparation and the parameters of spontaneous contractions; it did not prevent the effect of NaHS. The activator of K_ATP channels diazoxide (100 μM) caused a decrease in the basal tonus of the preparation, as well as the amplitude and frequency of spontaneous contractions. Diazoxide and the K_ATP channel blocker glibenclamide (50 μM) prevented the effect of NaHS on the tonus of the preparation. BaCl₂, the K_ir channel blocker (30 μM), caused an increase in the amplitude of spontaneous contractions and prevented the development of the NaHS inhibitory effects on the frequency and amplitude of spontaneous contractions; the decrease in tonus was less pronounced than in the control. Thus, a decrease in the basal tonus of the rat jejunum preparation under the action of the H₂S donor was associated with activation of K_ir channels, including K_ATP channels, whereas the effect of H₂S on amplitude and frequency was mediated by an increase in Ba²⁺-sensitive conductivity.

Neurotrauma is among the main causes of human disability and mortality. However, the mechanisms that mediate the survival and death of cells in the peripheral nervous system are still not fully understood. The transcription factors p53 and E2F1 are the master regulators of basic cellular functions, including DNA repair, cell cycle, metabolism, and apoptosis. Overexpression of p53 and E2F1, shown in a number of experimental models of peripheral nerve injury, suggests an important role of these proteins in the pathogenesis of neurotrauma. This review discusses the epigenetic mechanisms of p53 and E2F1 activation and regulation, which may contribute to the survival or death of neurons and glial cells after traumatic injury. Prospects for further studies of the mechanisms of regulation of the p53 and E2F1 proteins, including those involving histone deacetylases, for the development of neuroprotectors are considered.