scholarly journals Selection for constrained peptides that bind to a single target protein

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Andrew M. King ◽  
Daniel A. Anderson ◽  
Emerson Glassey ◽  
Thomas H. Segall-Shapiro ◽  
Zhengan Zhang ◽  
...  
Keyword(s):  
Proof Of Concept ◽  
Protein Target ◽  
Single Target ◽  
Single Protein ◽  
Σ Factor ◽  
Modified Peptides ◽  
Constrained Peptides ◽  
Selection For ◽  
Similar Affinity

AbstractPeptide secondary metabolites are common in nature and have diverse pharmacologically-relevant functions, from antibiotics to cross-kingdom signaling. Here, we present a method to design large libraries of modified peptides in Escherichia coli and screen them in vivo to identify those that bind to a single target-of-interest. Constrained peptide scaffolds were produced using modified enzymes gleaned from microbial RiPP (ribosomally synthesized and post-translationally modified peptide) pathways and diversified to build large libraries. The binding of a RiPP to a protein target leads to the intein-catalyzed release of an RNA polymerase σ factor, which drives the expression of selectable markers. As a proof-of-concept, a selection was performed for binding to the SARS-CoV-2 Spike receptor binding domain. A 1625 Da constrained peptide (AMK-1057) was found that binds with similar affinity (990 ± 5 nM) as an ACE2-derived peptide. This demonstrates a generalizable method to identify constrained peptides that adhere to a single protein target, as a step towards “molecular glues” for therapeutics and diagnostics.

scholarly journals Multiple gonococcal opacity proteins are expressed during experimental urethral infection in the male.

1994 ◽  
Vol 179 (3) ◽  
pp. 911-920 ◽  
Author(s):  
A E Jerse ◽  
M S Cohen ◽  
P M Drown ◽  
L G Whicker ◽  
S F Isbey ◽  
...  
Keyword(s):  
Antigenic Variation ◽  
Outer Membrane Proteins ◽  
Predominant Type ◽  
Detectable Difference ◽  
Single Protein ◽  
Selection For ◽  
Opacity Proteins ◽  
Strain Fa1090

The opacity (Opa) proteins of Neisseria gonorrhoeae are a family of outer membrane proteins demonstrating phase and antigenic variation. N. gonorrhoeae strain FA0190 has 11 opa loci that encode at least 8 antigenically distinct Opa proteins. To determine if expression of one Opa protein or a subset of them is favored during gonococcal infection, we inoculated Opa-negative variants of strain FA1090 intraurethrally into male volunteers. The Opa phenotype of gonococci isolated from urine and urethral swab cultures from nine infected subjects was determined. Opa proteins were expressed in a large proportion of the reisolates from the infected subjects. Gonococci cultured from urine or urethral swab samples from six of the subjects were uniformly Opa positive, with the predominant Opa variants differing among subjects. Three different Opa proteins were represented as the predominant type in at least one subject each. In three subjects, there was more heterogeneity in Opa phenotype of the reisolates, including the presence of Opa-negative variants. An increase in the proportion of isolates expressing multiple Opa proteins occurred over time in most subjects. Passage of the inoculum in vitro did not result in similar changes in Opa expression. There was no detectable difference in infectivity of an Opa-negative variant and one expressing an Opa protein (OpaF) that was highly represented in reisolates from the original nine subjects. Reisolates from three infected volunteers inoculated with the OpaF variant showed continued expression of OpaF alone or in conjunction with other Opa proteins. These results demonstrate that there is strong selection for expression of one or more Opa proteins by strain FA1090 in vivo, but that no single protein is preferentially expressed during early infection in the male urethra.

Improvement of effectiveness in maize breeding

2006 ◽  
Vol 54 (3) ◽  
pp. 351-358 ◽  
Author(s):  
P. Pepó
Keyword(s):  
Recurrent Selection ◽  
Genetic Manipulation ◽  
Field Testing ◽  
Tissue Cultures ◽  
Maize Breeding ◽  
Breeding Programmes ◽  
Speed Up ◽  
Selection For

Plant regeneration via tissue culture is becoming increasingly more common in monocots such as maize (Zea mays L.). Pollen (gametophytic) selection for resistance to aflatoxin in maize can greatly facilitate recurrent selection and the screening of germplasm for resistance at much less cost and in a shorter time than field testing. In vivo and in vitro techniques have been integrated in maize breeding programmes to obtain desirable agronomic attributes, enhance the genes responsible for them and speed up the breeding process. The efficiency of anther and tissue cultures in maize and wheat has reached the stage where they can be used in breeding programmes to some extent and many new cultivars produced by genetic manipulation have now reached the market.

scholarly journals The Multifunctional Sactipeptide Ruminococcin C1 Displays Potent Antibacterial Activity In Vivo as Well as Other Beneficial Properties for Human Health

2021 ◽  
Vol 22 (6) ◽  
pp. 3253
Author(s):  
Clarisse Roblin ◽  
Steve Chiumento ◽  
Cédric Jacqueline ◽  
Eric Pinloche ◽  
Cendrine Nicoletti ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Human Health ◽  
Biological Activities ◽  
Resistant Bacteria ◽  
Modified Peptides ◽  
The 1960S ◽  
Conventional Antibiotics ◽  
Clinical Potential

The world is on the verge of a major antibiotic crisis as the emergence of resistant bacteria is increasing, and very few novel molecules have been discovered since the 1960s. In this context, scientists have been exploring alternatives to conventional antibiotics, such as ribosomally synthesized and post-translationally modified peptides (RiPPs). Interestingly, the highly potent in vitro antibacterial activity and safety of ruminococcin C1, a recently discovered RiPP belonging to the sactipeptide subclass, has been demonstrated. The present results show that ruminococcin C1 is efficient at curing infection and at protecting challenged mice from Clostridium perfringens with a lower dose than the conventional antibiotic vancomycin. Moreover, antimicrobial peptide (AMP) is also effective against this pathogen in the complex microbial community of the gut environment, with a selective impact on a few bacterial genera, while maintaining a global homeostasis of the microbiome. In addition, ruminococcin C1 exhibits other biological activities that could be beneficial for human health, as well as other fields of applications. Overall, this study, by using an in vivo infection approach, confirms the antimicrobial clinical potential and highlights the multiple functional properties of ruminococcin C1, thus extending its therapeutic interest.

scholarly journals An integrated framework for quantifying immune-tumour interactions in a 3D co-culture model

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gheed Al-Hity ◽  
FengWei Yang ◽  
Eduard Campillo-Funollet ◽  
Andrew E. Greenstein ◽  
Hazel Hunt ◽  
...  
Keyword(s):  
Immune System ◽  
Immune Cell ◽  
In Vitro Models ◽  
Proof Of Concept ◽  
Culture Model ◽  
Spheroid Growth ◽  
Confocal Images ◽  
Cancer Spheroids

AbstractInvestigational in vitro models that reflect the complexity of the interaction between the immune system and tumours are limited and difficult to establish. Herein, we present a platform to study the tumour-immune interaction using a co-culture between cancer spheroids and activated immune cells. An algorithm was developed for analysis of confocal images of the co-culture to evaluate the following quantitatively; immune cell infiltration, spheroid roundness and spheroid growth. As a proof of concept, the effect of the glucocorticoid stress hormone, cortisol was tested on 66CL4 co-culture model. Results were comparable to 66CL4 syngeneic in vivo mouse model undergoing psychological stress. Furthermore, administration of glucocorticoid receptor antagonists demonstrated the use of this model to determine the effect of treatments on the immune-tumour interplay. In conclusion, we provide a method of quantifying the interaction between the immune system and cancer, which can become a screening tool in immunotherapy design.

scholarly journals Preclinical Development of Autologous Hematopoietic Stem Cell-Based Gene Therapy for Immune Deficiencies: A Journey from Mouse Cage to Bed Side

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 549
Author(s):  
Laura Garcia-Perez ◽  
Anita Ordas ◽  
Kirsten Canté-Barrett ◽  
Pauline Meij ◽  
Karin Pike-Overzet ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Severe Combined Immunodeficiency ◽  
Good Manufacturing Practice ◽  
Proof Of Concept ◽  
Preclinical Development ◽  
Hematopoietic Stem ◽  
Immune Deficiencies ◽  
Suitable Vector

Recent clinical trials using patient’s own corrected hematopoietic stem cells (HSCs), such as for primary immunodeficiencies (Adenosine deaminase (ADA) deficiency, X-linked Severe Combined Immunodeficiency (SCID), X-linked chronic granulomatous disease (CGD), Wiskott–Aldrich Syndrome (WAS)), have yielded promising results in the clinic; endorsing gene therapy to become standard therapy for a number of diseases. However, the journey to achieve such a successful therapy is not easy, and several challenges have to be overcome. In this review, we will address several different challenges in the development of gene therapy for immune deficiencies using our own experience with Recombinase-activating gene 1 (RAG1) SCID as an example. We will discuss product development (targeting of the therapeutic cells and choice of a suitable vector and delivery method), the proof-of-concept (in vitro and in vivo efficacy, toxicology, and safety), and the final release steps to the clinic (scaling up, good manufacturing practice (GMP) procedures/protocols and regulatory hurdles).

scholarly journals Apohemoglobin-haptoglobin complex attenuates the pathobiology of circulating acellular hemoglobin and heme

2020 ◽  
Vol 318 (5) ◽  
pp. H1296-H1307 ◽  
Author(s):  
Carlos J. Munoz ◽  
Ivan S. Pires ◽  
Jin Hyen Baek ◽  
Paul W. Buehler ◽  
Andre F. Palmer ◽  
...  
Keyword(s):  
Therapeutic Strategy ◽  
Capillary Density ◽  
Microvascular Blood Flow ◽  
Systemic Hypertension ◽  
Proof Of Concept ◽  
Heme Transfer ◽  
Ligand Transfer ◽  
Novel Therapeutic

This study highlights the apoHb-Hp complex as a novel therapeutic strategy to attenuate the adverse systemic and microvascular responses to intravascular Hb and heme exposure. In vitro and in vivo Hb exchange and heme transfer experiments demonstrated proof-of-concept Hb/heme ligand transfer to apoHb-Hp. The apoHb-Hp complex reverses Hb- and heme-induced systemic hypertension and microvascular vasoconstriction, preserves microvascular blood flow, and functional capillary density. In summary, the unique properties of the apoHb-Hp complex prevent adverse systemic and microvascular responses to Hb and heme-albumin exposure and introduce a novel therapeutic approach to facilitate simultaneous removal of extracellular Hb and heme.

scholarly journals CircRNA-SORE mediates sorafenib resistance in hepatocellular carcinoma by stabilizing YBX1

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Junjie Xu ◽  
Lin Ji ◽  
Yuelong Liang ◽  
Zhe Wan ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Nuclear Interaction ◽  
Circular Rna ◽  
Advanced Hepatocellular Carcinoma ◽  
Proof Of Concept ◽  
Potential Strategy ◽  
Oncogenic Protein ◽  
Hcc Cells

AbstractSorafenib is the first-line chemotherapeutic therapy for advanced hepatocellular carcinoma (HCC). However, sorafenib resistance significantly limits its therapeutic efficacy, and the mechanisms underlying resistance have not been fully clarified. Here we report that a circular RNA, circRNA-SORE (a circular RNA upregulated in sorafenib-resistant HCC cells), plays a significant role in sorafenib resistance in HCC. We found that circRNA-SORE is upregulated in sorafenib-resistant HCC cells and depletion of circRNA-SORE substantially increases the cell-killing ability of sorafenib. Further studies revealed that circRNA-SORE binds the master oncogenic protein YBX1 in the cytoplasm, which prevents YBX1 nuclear interaction with the E3 ubiquitin ligase PRP19 and thus blocks PRP19-mediated YBX1 degradation. Moreover, our in vitro and in vivo results suggest that circRNA-SORE is transported by exosomes to spread sorafenib resistance among HCC cells. Using different HCC mouse models, we demonstrated that silencing circRNA-SORE by injection of siRNA could substantially overcome sorafenib resistance. Our study provides a proof-of-concept demonstration for a potential strategy to overcome sorafenib resistance in HCC patients by targeting circRNA-SORE or YBX1.

Biochemical and genetic characterization of a yeast TFIID mutant that alters transcription in vivo and DNA binding in vitro

1992 ◽  
Vol 12 (5) ◽  
pp. 2372-2382
Author(s):  
K M Arndt ◽  
S L Ricupero ◽  
D M Eisenmann ◽  
F Winston
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Direct Repeat ◽  
Single Amino Acid ◽  
Wild Type ◽  
Dna Binding Specificity ◽  
Selection For

A mutation in the gene that encodes Saccharomyces cerevisiae TFIID (SPT15), which was isolated in a selection for mutations that alter transcription in vivo, changes a single amino acid in a highly conserved region of the second direct repeat in TFIID. Among eight independent spt15 mutations, seven cause this same amino acid change, Leu-205 to Phe. The mutant TFIID protein (L205F) binds with greater affinity than that of wild-type TFIID to at least two nonconsensus TATA sites in vitro, showing that the mutant protein has altered DNA binding specificity. Site-directed mutations that change Leu-205 to five different amino acids cause five different phenotypes, demonstrating the importance of this amino acid in vivo. Virtually identical phenotypes were observed when the same amino acid changes were made at the analogous position, Leu-114, in the first repeat of TFIID. Analysis of these mutations and additional mutations in the most conserved regions of the repeats, in conjunction with our DNA binding results, suggests that these regions of the repeats play equivalent roles in TFIID function, possibly in TATA box recognition.

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