Assessment of the effectiveness of the peptide inhibitor homologous to the transforming growth factor ß cytokine blocking the TGFßRI/TGFßRII receptor complex-pilot study.

BACKGROUND: A key player in the fibrotic process is the transforming growth factor ß (TGF-ß) which enhances extracellular matrix production by increasing the transcription of matrix proteins. The cytokine TGF-ß first binds to the TGFßRII receptor (dimer), resulting in the recruitment of the TGFßRI receptor (dimer). The complex thus formed leads to the phosphorylation of the kinase domain of TGFßRI, which in turn results in activation of the Smad pathway. This is therefore a targeted pathway for research into the application of peptide inhibitors in blocking the TGF-ß-Smad signaling pathway. The aim of this study was to design a peptide inhibitor (homologous to the cytokine TGF-ß) which, after binding to the TGFßRI/TGFßRII receptor, would block the cytokine binding and thus prevent the formation of an activating complex. METHODS: Preliminary work on the design and synthesis of inhibitors for TGFßRI/TGFßRII has allowed us to identify and describe five key regions of the TGF-ß-TGFßRI/TGFßRII interface. The following five peptide inhibitors were synthesized for Region 1: 1.1 ALDAAYCFR, 1.2 LDAAYCFRN, 1.3 DAAYCFRNV, 1.4 AAYCFRNVQ, 1.5 AYCFRNVQD. The expression of the SEAP reporter gene, Smad2, Smad3, Smad4, and JNK1 gene was measured using quantitative real-time polymerase chain reaction. RESULTS: For Region 1 peptide inhibitors tested for TGFßRI/TGFßRII, reduced SEAP (reporter gene) expression was observed in cells of the MFB-F11 line, which suggests inhibited the formation of cytokine-receptor complexes. CONCLUSIONS: For IP1_2, 1_3 and 1_5 Region 1 peptides tested for TGFßRI/TGFßRII, reduced cytokine-receptor signal by adding newly designed inhibitors. The study revealed an impact of these peptide inhibitors on the reduction of mRNA expression of Smad2, Smad3, Smad4 and JNK1 genes.

Antidepressant mechanisms of ketamine's action: NF-κB in the spotlight.

Ketamine recently approved for therapy of treatment-resistant depression shows a complex and not fully understood mechanism of action. Apart from its classical glutamatergic N-methyl-D-aspartate receptor antagonistic action, it is thought that anti-inflammatory properties of the drug are of clinical relevance due to the contribution of activated inflammatory mediators to the pathophysiology of depression and non-responsiveness of a group of patients to current antidepressant therapies. In a search of the mechanism underlying anti-inflammatory effects of ketamine, the nuclear factor kappa B transcription factor (NF-κB) has been proposed as a target for ketamine. The NF-κB forms precisely regulated protein signaling cascades enabling a rapid response to cellular stimuli. In the central nervous systems, NF-κB signaling appears to have pleiotropic but double-edged functions: on the one hand it participates in the regulation of processes that are crucial in the treatment of depression, such as neuroplasticity, neurogenesis or neuronal survival, on the other - in the activation of neuroinflammation and cell death. Ketamine has been found to reduce inflammation mediated by NF-κB, leading to decreased level of pro-inflammatory cytokines and other inflammatory or stress mediators. Therefore, this review presents recent data on the significance of the NF-κB cascade in the mechanism of ketamine's action and its future perspectives in designing new strategies for the treatment of depression.