Biology subjects

Ozcelik, C. E.

Publications and source records attributed to Ozcelik, C. E..

5 recordsLinked to original sources

bioRxiv2023

Screening Peptide Drug Candidates to Neutralize Whole Viral Agents : A Case study with SARS-CoV-2 Virus

Covid19 pandemic revealed the reality for the need of therapeutic and pharmaceutical molecule development in a short time with different approaches. Although the enhancement of immunological memory by vaccination was the quicker and robust strategy, still medication is required for immediate treatment for a patient. For this purpose, one of the approaches is developing new therapeutic molecule development like peptide-based drugs. Also, peptides can be used developing other molecules like nanobodies. Here, M13 phage display library was used for selecting SARS-CoV-2 interacting peptides for developing a neutralizing molecule for further use. Biopanning was applied with four iterative cycles to select phages displaying different 12-amino acid-long peptides. Then, the M13 phage genomic region where peptide sequences expressed were analyzed and sequences were obtained. Randomly selected peptide sequences were synthesized by solid-state peptide synthesis method. These peptides were analyzed by quartz crystal microbalance method in terms or peptide interaction capacity with specifically wild-type S protein. Next, QCM data was further validated by enzyme-linked immunosorbent assay (ELISA) in order to check peptides according to their neutralizing capacity rather than binding to S1 protein. The results showed that, phage display served an opportunity for selecting peptides which can be used and developed further as pharmaceutical molecules. More specifically, scpep3, scpep8 and scpep10 had both binding and neutralizing capacity for S1 protein as a candidate for therapeutic molecule.

bioengineering↗

bioRxiv2023

A Synthetic Protein Secretion System for Living Bacterial Therapeutics

Bacteria species can thrive and colonize different parts of the human body. Those naturally residing at disease sites e.g., tumors and gut can be designed for targeted protein delivery which can provide better clinical profiles for protein-based therapies. Therefore, a generalizable, efficient, and safe protein secretion system would a be valuable tool to engineer therapeutically active microbes, especially for gram-negative species due to the presence of the second cell wall. Here, we propose an approach called iLOM-SS, an acronym for inducible Leaky Outer Membrane based Secretion System, to secrete proteins in gram-negative bacteria (GNB). In iLOM-SS, the outer membrane of GNB is made permeable by transient suppression of structural protein(s) to enable free diffusion of cargo proteins expressed at the periplasm. To validate this approach, an iLOM-SS is constructed in Escherichia coli Nissle 1917 (EcN) strain. Proteins including enzymes and a human cytokine were proven to be secreted with iLOM-SS by EcN in vitro. Further characterizations of iLOM-SS in ECN showed that fast and titratable secretion, a stop switch design for secretion, and functional implementation of the secretion system in different genetic circuit architectures were possible. We foresee that this work will pave the way for designing GNB to secrete proteins for diverse arrays of applications including but not limited to the development of sentinel cells for therapeutic purposes.

synthetic biology↗

bioRxiv2023

Highly Potent Peptide Therapeutics To Prevent Protein Aggregation In Huntington s Disease

Huntingtons disease (HD) is a progressive, autosomal dominant neurodegenerative disorder resulting from a significant amplification of CAG repeats in exon 1 of the Huntingtin (Htt) gene. More than 36 CAG repeats result in the formation of mutant Htt (mHtt) protein. These amino-terminal mHtt fragments lead to the formation of misfolded proteins, which then form aggregates in relevant brain regions. Available treatments concentrate primarily on alleviating the diseases symptoms. Therefore, therapies that can delay the progression of the disease are imperative to halt the course of the disease. Peptide-based drug therapies provide such a platform. Inhibitory peptides were screened against monomeric units of both wild type (Htt(Q25)) and mHtt fragments, including Htt(Q46)and Htt(Q103). It was accomplished by utilizing several display technologies. This study focuses on the in-vitro characterization of the screened peptides. Fibril kinetics was studied in real-time utilizing the Thioflavin T (ThT) assay. The impact of specific peptides on fibril formation was examined by observing the change in fluorescence signal. Atomic force microscopy was also used to study the influence of peptides on fibril formation. Three of the six chosen peptides (HHGANSLSLVSQD, HGLHSMHNKLTR, and WMFPSLKLLDYH) effectively inhibited aggregation. These experiments demonstrate that the chosen peptides suppress the formation of fibrils in mHtt proteins and can provide a therapeutic lead for further optimization and development.

neuroscience↗

bioRxiv2023

Synergistic Screening of Peptide-Based Biotechnological Drug Candidates for Neurodegenerative Diseases using Yeast Display and Phage Display

Peptide therapeutics are robust and promising molecules for treating diverse disease conditions. These molecules can be developed from naturally occurring or mimicking native peptides, through rational design and peptide libraries. We developed a new platform for the rapid screening of the peptide therapeutics for disease targets. In the course of the study, we aimed to employ our platform to screen a new generation of peptide therapeutics candidates against aggregation prone protein targets. Two peptide drug candidates for the protein aggregation prone diseases namely Parkinsons and Alzheimers diseases were screened. Currently, there are several therapeutic applications that are only effective in masking or slowing down symptom development. Nonetheless, different approaches are developed for inhibiting amyloid aggregation in the secondary nucleation phase, which is critical for amyloid fibril formation. Instead of targeting secondary nucleated protein structures, we tried to inhibit monomeric amyloid units as a novel approach for halting disease-condition. To achieve this, we combined yeast surface display and phage display library platforms. We expressed -synuclein, amyloid {beta}40, and amyloid {beta}42 on yeast surface, and we selected peptides by using phage display library. After iterative biopanning cycles optimized for yeast cells, several peptides were selected for interaction studies. All of the peptides have been used in vitro characterization methods which are QCM-D measurement, AFM imaging, and ThT assay, and they have yielded promising results in order to block fibrillization or interact with amyloid units as a sensor molecule candidate. Therefore, peptides are good choice for diverse disease-prone molecule inhibition particularly those inhibiting fibrillization. Additionally, these selected peptides can be used as drugs and sensors to detect disease quickly and halt disease progression. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=77 SRC="FIGDIR/small/536742v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@50c81dorg.highwire.dtl.DTLVardef@181fea5org.highwire.dtl.DTLVardef@17539c7org.highwire.dtl.DTLVardef@1244a00_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2021

A Highly Potent SARS-CoV-2 Blocking Lectin Protein

COVID-19 pandemic effected more than 180 million people around the globe causing more than four million deaths as of July 2021. Sars-CoV-2, the new coronavirus, has been identified as the primary cause of the infection. The number of vaccinated people is increasing however prophylactic drugs are highly demanded to ensure a secure social contact. There have been a number of drug molecules repurposed to fight against Sars-CoV-2, however the proofs for the effectiveness of these drug candidates is limited. Here we demonstrated griffithsin (GRFT), a lectin protein, to block the entry of the Sars-CoV2 into the Vero6 cell lines and IFNAR-/-mouse models by attaching to spike protein of the Sars-CoV-2. Given the current mutation frequency of the Sars-CoV-2 we believe that GRFT protein-based drugs will have a high impact in preventing the transmission both on Wuhan strain as well as any other emerging variants including delta variant causing high speed spread of COVID-19.

biochemistry↗