Targeting Nrf2 with Probiotics and Postbiotics in the Treatment of Periodontitis

Periodontitis is a destructive disease of the tooth-surrounding tissues. Infection is the etiological cause of the disease, but its extent and severity depend on the immune-inflammatory response of the host. Immune cells use reactive oxygen species to suppress infections, and there is homeostasis between oxidative and antioxidant mechanisms during periodontal health. During periodontitis, however, increased oxidative stress triggers tissue damage, either directly by activating apoptosis and DNA damage or indirectly by activating proteolytic cascades. Periodontal treatment aims to maintain an infection and inflammation-free zone and, in some cases, regenerate lost tissues. Although mechanical disruption of the oral biofilm is an indispensable part of periodontal treatment, adjunctive measures, such as antibiotics or anti-inflammatory medications, are also frequently used, especially in patients with suppressed immune responses. Recent studies have shown that probiotics activate antioxidant mechanisms and can suppress extensive oxidative stress via their ability to activate nuclear factor erythroid 2-related factor 2 (Nrf2). The aim of this narrative review is to describe the essential role of Nrf2 in the maintenance of periodontal health and to propose possible mechanisms to restore the impaired Nrf2 response in periodontitis, with the aid of probiotic and postbiotics

Analysis of Chemical Structure and Antibiofilm Properties of Exopolysaccharides from Lactiplantibacillus plantarum EIR/IF-1 Postbiotics

Previous studies have indicated that the exopolysaccharides of lactic acid bacteria exhibit antibiofilm activity against non-oral bacteria by preventing their initial adhesion to surfaces and by downregulating the expression of genes responsible for their biofilm formation. The aims of this study were to (1) characterize the exopolysaccharides (EPSs) of Lactobacillus plantarum EIR/IF-1 postbiotics, (2) test their antibiofilm effect on dual biofilms, and (3) evaluate their bacterial auto-aggregation, co-aggregation, and hydrocarbon-binding inhibitory activity. The EPSs were characterized by FTIR, HPLC, and thermogravimetric analysis. Bacterial auto- and co-aggregation were tested by Kolenbrander's method and hydrocarbon binding was tested by Rosenberg's method. Dual biofilms were formed by culturing Fusobacterium nucleatum ATCC 25586 with one of the following bacteria: Prevotella denticola ATCC 33185, P. denticola AHN 33266, Porphyromonas gingivalis ATCC 33277, P. gingivalis AHN 24155, and Filifactor alocis ATCC 35896. The EPSs contained fractions with different molecular weights (51 and 841 kDa) and monosaccharides of glucose, galactose, and fructose. The EPSs showed antibiofilm activity in all the biofilm models tested. The EPSs may have inhibited bacterial aggregation and binding to hydrocarbons by reducing bacterial hydrophobicity. In conclusion, the EPSs of L. plantarum EIR/IF-1, which consists of two major fractions, exhibited antibiofilm activity against oral bacteria, which can be explained by the inhibitory effect of EPSs on the auto-aggregation and co-aggregation of bacteria and their binding to hydrocarbons.</p

Azido amino asitlerin hazırlanması ve doğal kimyasal bağlanma tepkimesinin klorotoksin sentezine uygulanması.

In this project, the pharmaceutically and biologically important peptide, chlorotoxin (CLTX), and some derivatives of CLTX containing azido amino acids was synthesized by using solid phase peptide synthesis (SPPS) based on 9-fluorenylmethyloxycarbonyl (Fmoc) chemistry strategy and native chemical ligation. The native chemical ligation provides more efficient than only SPPS. Directly synthesis of CLTX by SPPS has very low yield, by using native chemical ligation, the yield is aimed much higher. The CLTX can bind to matrix metalloproteinase-2 (MMP-2), which is involved in the breakdown of extracellular matrix in normal physiological processes and inhibit this enzyme. The important role of MMP-2 for spreading cancer cell is known from literature and the inhibition of this enzyme could potentially be used for treatment of cancer in the future. The inhibition mechanism of CLTX on MMP-2 has not been determined yet. There are imaging methods which involves functionalization of CLTX using fluorescence dyes from lysine residue which is not selective. The synthesis of CLTX derivatives containing azido amino acids could provide the selective functionalization of of CLTX using Huisgen ‘Click Chemistry’ together with propargyl dyes. The azido amino acids that are used for CLTX was synthesized by using new method 2-Azido-1,3-dimethylimidazolinium hexafluorophosphate (ADMP) from that own to free amine and hydroxyl group. ADMP can make di-azo transfer to primary amine group and also replacement between azide and hydroxyl group.M.S. - Master of Scienc

Synthesis of Chlorotoxin by Native Chemical Ligation

Chlorotoxin (CLTX) is a neurotoxin found in the venom of the Israeli scorpion, Leirius quinquestriatus. It contains 36-amino acids with four disulfide bonds and inhibits low-conductance chloride channels. CLTX also binds to matrix metalloproteinase-2 (MMP-2) selectively. The synthesis of chlorotoxin using solid phase peptide synthesis (SPPS) is very difficult and has a very low yield (<1%) due to high number of amino acid sequence. In this work, to improve the efficiency of the synthesis, native chemical ligation was applied. In this strategy, chlorotoxin sequence was split into two parts having 15 and 21 amino acids. 21-mer peptide was synthesized in its native form based on 9-fluorenylmethyloxycarbonyl (Fmoc) chemistry. 15-mer peptide was synthesized having o-aminoanilide linker on C-terminal. These parts were coupled by native chemical ligation to produce chlorotoxin

FEN BİLİMLERİ ENSTİTÜSÜ/LİSANSÜSTÜ TEZ PROJESİ

KÖK HÜCRE SAFLAŞTIRILMASI İÇİN UCUZ VE YÜKSEK VERİMLİ MİKRO-MEKANİK SİSTEMLERİN TASARIMI VE ÜRETİM

Synthesis of Chlorotoxin by Native Chemical Ligation

Chlorotoxin (CLTX) is a neurotoxin found in the venom of the Israeli scorpion, Leirius quinquestriatus. It contains 36-amino acids with four disulfide bonds and inhibits low-conductance chloride channels. CLTX also binds to matrix metalloproteinase-2 (MMP-2) selectively. The synthesis of chlorotoxin using solid phase peptide synthesis (SPPS) is very difficult and has a very low yield (<1%) due to high number of amino acid sequence. In this work, to improve the efficiency of the synthesis, native chemical ligation was applied. In this strategy, chlorotoxin sequence was split into two parts having 15 and 21 amino acids. 21-mer peptide was synthesized in its native form based on 9-fluorenylmethyloxycarbonyl (Fmoc) chemistry. 15-mer peptide was synthesized having o-aminoanilide linker on C-terminal. These parts were coupled by native chemical ligation to produce chlorotoxin

Targeting Nrf2 with Probiotics and Postbiotics in the Treatment of Periodontitis

Periodontitis is a destructive disease of the tooth-surrounding tissues. Infection is the etiological cause of the disease, but its extent and severity depend on the immune–inflammatory response of the host. Immune cells use reactive oxygen species to suppress infections, and there is homeostasis between oxidative and antioxidant mechanisms during periodontal health. During periodontitis, however, increased oxidative stress triggers tissue damage, either directly by activating apoptosis and DNA damage or indirectly by activating proteolytic cascades. Periodontal treatment aims to maintain an infection and inflammation-free zone and, in some cases, regenerate lost tissues. Although mechanical disruption of the oral biofilm is an indispensable part of periodontal treatment, adjunctive measures, such as antibiotics or anti-inflammatory medications, are also frequently used, especially in patients with suppressed immune responses. Recent studies have shown that probiotics activate antioxidant mechanisms and can suppress extensive oxidative stress via their ability to activate nuclear factor erythroid 2-related factor 2 (Nrf2). The aim of this narrative review is to describe the essential role of Nrf2 in the maintenance of periodontal health and to propose possible mechanisms to restore the impaired Nrf2 response in periodontitis, with the aid of probiotic and postbiotics

Pumping Between Phases With a Pulsed-Fuel Molecular Ratchet

The sorption of species from solution into and onto solids, surfaces, crystals, gels and other matrices, underpins the sequestering of waste and pollutants, the recovery of precious metals, heterogeneous catalysis, many forms of chemical and biological analysis and separation science, and numerous other technologies. In such cases the transfer of the substrate between phases tends to proceed spontaneously, in the direction of equilibrium. Molecular ratchet mechanisms, where kinetic gating selectively inhibits or accelerates particular steps in a process, makes it possible to drive dynamic systems out of equilibrium. Here we report on a small-molecule pump immobilised on and near the surface of polymer beads, that uses an energy ratchet mechanism to actively transport substrates from solution onto the beads away from equilibrium. One complete cycle of the pump occurs with each pulse of a chemical fuel, synchronizing the ratchet dynamics so that the immobilised molecular machines all act in unison. Upon addition of the trichloroacetic acid fuel, micrometre-diameter polystyrene beads functionalised with an average of ~8×10exp10 molecular pumps per bead, sequester from solution crown ethers appended with a fluorescent tag. Following consumption of the fuel, the rings are mechanically trapped in a higher energy, out-of-equilibrium, state on the beads and cannot be removed by dilution nor by switching the binding interactions off. This differs from dissipative assembled materials that require a continuous supply of energy to persist. Addition of a second pulse of fuel causes the uptake of more macrocycles, which can be labelled with a different fluorescent tag. This drives the system progressively further away from equilibrium and also confers sequence information on the deposited structure. The polymer-bound substrates (and the stored energy) can subsequently be released back to the bulk on demand, either emptying one compartment at a time or all at once. Non-equilibrium sorption by using immobilised artificial molecular machines to pump substrates from solution onto and into materials, offers potential for the transduction of energy from chemical fuels for the storage and release of energy and information

Postbiotics of the <i>Lactiplantibacillus plantarum</i> EIR/IF-1 Strain Show Antimicrobial Activity against Oral Microorganisms with pH Adaptation Capability

Postbiotics offer better properties than probiotics. This study investigated the antimicrobial activity of Lactiplantibacillus plantarum EIR/IF-1 postbiotics against pH-adaptive bacteria, namely Prevotella denticola, Fusobacterium nucleatum, and Streptococcus sanguinis. Cell-free culture media of L. plantarum EIR/IF-1 were used as postbiotics in either crude (acidic) or neutralized form to also understand non-pH-dependent antimicrobial potential. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and viable cell counts were determined for crude and neutralized postbiotics. Culture media adjusted to different pH values were also compared to adjusted media with postbiotics to understand the strength of organic acids in postbiotics. Antibiofilm activity of postbiotics was determined against polymicrobial biofilm formation. Finally, the toxicity of crude postbiotics was tested on human periodontal ligament fibroblast cells (hPDLFCs). MIC values of crude postbiotics were 12.5 mg/mL for all strains. F. nucleatum and P. denticola strains were sensitive to neutralized postbiotics after 48 h of incubation. Moreover, 12.5 and 25 mg/mL postbiotics inhibited biofilm formation and 2.5 mg/mL and lower concentrations of crude postbiotics showed no cytotoxicity in hPDLFCs. This study showed that postbiotics have antimicrobial activity against pH-adaptive oral bacteria and no cytotoxic effect on hPDLFCs depending on the dose. The non-acidic antimicrobial components of postbiotics could also enable their safe use in the oral cavity