Characterization of particulate matter binding peptides screened from phage display

Effects of (-)-Loliolide against Fine Dust Preconditioned Keratinocyte Media-Induced Dermal Fibroblast Inflammation

At present air pollution in parts of East Asia is at an alarming level due to elevated levels of fine dust (FD). Other than pulmonary complications, FD was found to affect the pathogenesis of ROS-dependent inflammatory responses via penetrating barrier-disrupted skin, leading to degradation of extracellular matrix components through the keratinocyte-fibroblast axis. The present study discloses the evaluation of human dermal fibroblast (HDF) responses to FD preconditioned human keratinocyte media (HPM) primed without and with (-)-loliolide (HTT). HPM-FD treatment increased the ROS level in HDFs and activated mitogen-activated protein kinase-derived nuclear factor (NF)-κB inflammatory signaling pathways with a minor reduction of viability. The above events led to cell differentiation and production of matrix metalloproteinases (MMP), increasing collagenase and elastase activity despite the increase of tissue inhibitors of metalloproteinases (TIMP). Media from HTT primed keratinocytes stimulated with FD indicated ameliorated levels of MMPs, inflammatory cytokines, and chemokines in HDFs with suppressed collagenase and elastase activity. Present observations help to understand the factors that affect HDFs in the microenvironment of FD exposed keratinocytes and the therapeutic role of HTT as a suppressor of skin aging. Further studies using organotypic skin culture models could broaden the understanding of the effects of FD and the therapeutic role of HTT.

Systematic Screening and Deep Analysis of CoPt Binding Peptides Leads to Enhanced CoPt Nanoparticles Using Designed Peptides

Using protein and peptide additives to direct the crystallization of inorganic materials is a very attractive and environmentally friendly strategy to access complex and sometimes inaccessible mineral phases. CoPt is a very desirable high-magnetoanisotropic material in its L1₀ phase, but this is acquired by annealing at high temperatures which is incompatible with delicate nanomaterial assembly. Previous studies identified one peptide with high affinity to CoPt and four peptides with high affinity to FePt L1₀ phase nanoparticles (NPs) through phage display biopanning selection. While synthesis mediated by these peptides offered a small degree of L1₀ character to the NPs, they do not have the magnetoanistropy required for applications. In this study, we improve the activity of peptide directed crystallization by designing second generation peptides. We use the five literature sequences (LS) to probe the binding affinity deeper through dissection (alanine scanning), reduction (truncations), and substitution of the LS to find key amino acids and motifs. This is performed using a SPOT peptide array, importantly probing interactions at three stages of NP formation: with precursor, during synthesis, and with NPs. We found four universal features: 1) the importance of basic residues, particularly lysine flanking both ends of the sequence; 2) the importance of methionine; 3) shorter sequences show higher affinity than longer ones; and 4) acidic residues have a negative impact on binding with aspartic acid less favorable than glutamic acid. However, an acidic amino acid benefits, presumably to balance charge. The short motif KSLS had high affinity in all assays. Three sequences were selected from the screening, and three sequences were designed from the rules above. These were used to mediate a green synthesis of CoPt nanoparticles. The screened peptides mediated the formation of NPs with improved coercivity (90-110 Oe) compared to the LS (30-80 Oe), while the designed peptides facilitated formation of CoPt NPs with the highest coercivity (109 to 132 Oe), representing a massive improvement on L1₀ character. This result along with deeper insight this methodology brings offers vast potential for the future.

Array-Based Screening of Silver Nanoparticle Mineralization Peptides

The use of biomolecules in nanomaterial synthesis has received increasing attention, because they can function as a medium to produce inorganic materials in ambient conditions. Short peptides are putative ligands that interact with metallic surfaces, as they have the potential to control the synthesis of nanoscale materials. Silver nanoparticle (AgNP) mineralization using peptides has been investigated; however, further comprehensive analysis must be carried out, because the design of peptide mediated-AgNP properties is still highly challenging. Herein, we employed an array comprising 200 spot synthesis-based peptides, which were previously isolated as gold nanoparticle (AuNP)-binding and/or mineralization peptides, and the AgNP mineralization activity of each peptide was broadly evaluated. Among 10 peptides showing the highest AgNP-synthesis activity (TOP10), nine showed the presence of EE and E[X]E (E: glutamic acid, and X: any amino acid), whereas none of these motifs were found in the WORST25 (25 peptides showing the lowest AgNP synthesis activity) peptides. The size and morphology of the particles synthesized by TOP3 peptides were dependent on their sequences. These results suggested not only that array-based techniques are effective for the peptide screening of AgNP mineralization, but also that AgNP mineralization regulated by peptides has the potential for the synthesis of AgNPs, with controlled morphology in environmentally friendly conditions.

Screening of peptide probe binding to particulate matter with a high metal content

Particulate matter (PM) is becoming an increasing health concern and there is a need to develop detection methods to keep its harmful effects in check. Generation of reactive oxygen species (ROS) by PM is often associated with metal compounds, hence our aim is to screen for a peptide probe towards improved collection and the detection of PM having a high metal content. Peptides are putative recognition molecules due to their versatility and ease of modification to enhance their binding selectivities. PM binding peptides were screened using the peptide array and different binding behaviors in terms of different spot colors (yellow, mixed and gray), indicating the different composition of bound PMs, were observed. The strongest binding peptides were identified as follows: NHVNTNYYPTLH (gray), NGYYPHSHSYHQ (mixed) and HHLHWPHHHSYT (yellow), with relative binding ratios of 125%, 144% and 136%, in comparison with WQDFGAVRSTRS, a peptide screened from a phage display in our previous study. Inductively coupled plasma mass spectrometry (ICPMS) analyses revealed that Co, Ni and Zn content in the PM bound to the HHLHWPHHHSYT peptide spot were respectively 12.5, 15.8 and 7.8 times that of the PM bound to no peptide spot, suggesting this peptide probe is applicable to collect PM with a high metal content.

Screening of bacteria-binding peptides and one-pot ZnO surface modification for bacterial cell entrapment

Short functional peptides are promising materials for use as targeting recognition probes. Toll-like receptor 4 (TLR4) plays an essential role in pathogen recognition and in activation of innate immunity. Here, the TLR4 amino acid sequence was used to screen for bacterial cell binding peptides using a peptide array. Several octamer peptides, including GRHIFWRR, demonstrated binding to Escherichia coli as well as lipopolysaccharides. Linking this peptide with the ZnO-binding peptide HKVAPR, creates a bi-functional peptide capable of one-step ZnO surface modification for bacterial cell entrapment. Ten-fold increase in entrapment of E. coli was observed using the bi-functional peptide. The screened peptides and the simple strategy for nanomaterial surface functionalization can be employed for various biotechnological applications including bacterial cell entrapment onto ZnO surfaces.

Linking the screened bacteria-binding peptide with the ZnO-binding peptide HKVAPR, created a bifunctional peptide capable of one-step simple ZnO surface modification and of bacterial cell entrapment.