Both acute brain injuries and neurodegenerative diseases are accompanied by neuroinflammation. The outcome of neuroinflammation and the prognosis of brain functional status depend on the balance of pro-inflammatory and anti-inflammatory factors. Many studies are aimed at finding possible therapeutic targets allowing to shift inflammatory response processes towards anti-inflammatory mechanisms. It has been shown that channels formed by pannexin proteins are expressed in all brain cells including astrocytes. However, their role in the processes of neuroinflammation is still unclear. Channels formed by pannexin 1 (Panx1) may be involved in proinflammatory activation of astrocytes induced by thrombin and/or lipopolysaccharide (LPS). The aim of this study was to assess thrombin- and LPS-induced activation of primary mouse cortical astrocytes under Panx1 blockade by probenecid. Functional profile of astrocytes, their proliferation and secretory activity changed both in case of thrombin application (50 nM and 100 nM) and in case of incubating cells with LPS. The observed increasing of nitric oxide (NO), β-hexosaminidase HEX and IL6 secretion stopped after the cells were treated with probenecid. Based on the obtained results, probenecid can be considered as a potential agent influencing the inflammatory process in brain tissue by stabilizing astrocytes through inactivation of Panx1 and reduction of astrogliosis.

Nejrovospalenie razvivaetsya v mozgovoj tkani kak pri ostryh povrezhdeniyah mozga, tak i pri nejrodegenerativnyh zabolevaniyah. Ot balansa provospalitel'nyh i protivovospalitel'nyh faktorov budet zaviset' iskhod nejrovospaleniya i prognoz funkcional'nogo sostoyaniya mozga. Poetomu cel'yu mnogih issledovanij yavlyaetsya poisk vozmozhnyh terapevticheskih mishenej, pozvolyayushchih sdvigat' hod vospalitel'noj reakcii v pol'zu realizacii protivospalitel'nyh mekhanizmov. Pokazano, chto kanaly, obrazovannye belkami panneksinami ekspressiruyutsya vo vsekh kletkah mozga, v tom chisle i v astrocitah. Odnako ih rol' v processah nejrovospaleniya poka ne yasna. Kanaly, sformirovannye panneksinom 1 (Panx1), mogut byt' vovlecheny v provospalitel'nuyu aktivaciyu astrocitov, induciruemuyu trombinom i/ili lipopolisaharidom (LPS). Cel'yu issledovaniya bylo ocenit' trombin- i LPS-vyzvannuyu aktivaciyu pervichnyh kortikal'nyh astrocitov myshi v usloviyah blokady Panx1 probenecidom. Ustanovleno, chto i v sluchae applikacii trombina (50 i 100 nM), i v sluchae inkubacii kletok s LPS, proiskhodit izmenenie funkcional'nogo profilya astrocitov, izmenyaetsya ih proliferaciya i sekretornaya aktivnost'. Nablyudaemoe pri etom uvelichenie sekrecii NO, β-geksozaminidazy (BGA) i IL6 prekrashchalos' na fone obrabotki kletok probenecidom. Poluchennye rezul'taty svidetel'stvuyut o vozmozhnosti rassmatrivat' probenecid v kachestve potencial'nogo agenta, vliyayushchego na vospalitel'nyj process v mozgovoj tkani putem stabilizacii astrocitov cherez inaktivaciyu Panx1 i snizhenie astroglioza.

The present study is focused on the problem of regulation of the proinflammatory activity of mast cells through a specific class of protease-activated receptors, PAR1. Here we show for the first time that a new peptide-agonist of PAR1 regulates the activity of the mast cells analog, cell line RBL-2H3. The peptide-agonist of PAR1, like activated protein C (APC), exerts anti-inflammatory and cytoprotective effects on RBL-2H3 cells, when they are activated by proinflammatory factors. Incubation of mast cells with lipopolysaccharide (LPS) induces a transient increase in the intracellular concentration of free calcium ions, enhances the histamine secretion, and suppresses cell proliferation. Pretreatment of the cells with the peptide or APC prevents the effect of endotoxin. Activation of the RBL-2H3 cells by thrombin and calcium ionophore leads to actin reorganization, which may indicate cell activation and secretion onset. Application of the peptide or APC in the presence of activators leads to the actin ordering in the cell submembrane region, which is typical for the control group. Thus, the newly discovered anti-inflammatory and protective properties of the peptide-agonist of PART (NPNDKYEPF-amide) open up the possibility of finding new approaches to the therapy of inflammatory processes on the basis of peptide drugs through the modulation of the PAR activity.

The present study focuses on possible ways to protect brain neurons during neuroinflammation. For the first time it is shown that peptide NPNDKYEPF amide, similar to activated protein C (APC), protects hippocampal neurons in a model of neuroinflammation induced by the toxic effects of endotoxin (lipopolysaccharide)-activated mast cells on neurons. It was found that the incubation of hippocampal neurons with mast cells activated by proinflammatory factors leads to neuronal apoptosis within 24 h after the exposure. Preincubation of mast cells with peptide NPNDKYEPF amide or with APC, before the toxin’s treatment, abolishes the toxic effects of the activated mast cells on neurons. By the blockade of protease-activated receptors of type 1 (PAR1), the receptor mechanism of the peptide action on mast cells and on neurons was identified. It was shown that PAR1 is required for the protective effect of the peptide in the conditions of neuroinflammation. Thus, peptide NPNDKYEPF amide is a neuroprotector, similar to APC, and can be used for the development of new approaches of the therapy of inflammatory processes accompanying different types of traumatic and ischemic brain damage.