Peptide deregulated in hypertrophic scar-1 alleviates hypertrophic scar fibrosis by targeting focal adhesion kinase and pyruvate kinase M2 and remodeling the metabolic landscape

Hypertrophic scarring is a fibrotic skin disease characterized by excessive deposition of collagens. Emerging evidence has suggested important roles for peptides in fibrosis-related diseases. Here, we demonstrate that a skin-derived endogenous peptide, peptide deregulated in hypertrophic scar-1 (PDHS1), with the sequence IATTTASAATAAAIGATPRAK, inhibits cell proliferation, promotes apoptosis, decreases the proportion of cells in S phase, and decreases collagen synthesis in hypertrophic scar fibroblasts. Additionally, treatment with PDHPS1 alleviates hypertrophic scarring in a rabbit ear model. PDHPS1 was found to bind to focal adhesion kinase (FAK) and to decrease its activity. PDHPS1 was also shown to bind to pyruvate kinase M2 (PKM2) and to decreased its expression. Smad2 phosphorylation is also inhibited by treatment with PDHPS1. Overexpression of FAK rescues the decreased expression of COL3A1 induced by PDHPS1 treatment. Targeted metabolomics revealed that PDHPS1 reprogramed metabolism that related to amino acid synthesis, leading to decreases of the key glycolysis intermediates glucose-6-phosphate and fructose-6-phosphate. These results demonstrated that the endogenous peptide PDHPS1 alleviates hypertrophic scar fibrosis in vitro and in vivo by targeting FAK and PKM2 and remodeling the metabolic landscape. Overall, treatment with PDHPS1 is a potential therapeutic strategy for hypertrophic scarring.

Pharmacokinetics of novel oral cyclic peptide

Protein and peptide drugs have been considered to be valuable for treating disease for many years, capturing more and more of the attention of researchers. Previously, we found a short peptide from the porcine intestine named COX52-69, which could simultaneously lower blood glucose and insulin response after intraperitoneal injection. And thus, it showed a potential to counter type II diabetes without leading to insulin resistance, mainly caused by high insulin levels in the blood. However, this molecule is not stable in the digestive system and cannot be used via oral administration. Here we employed the circularization technique to modify the peptide and tested its pharmacokinetics.

Preparation of DRV Liposomes

Dried reconstituted vesicle (DRV) liposomes are formulated under mild conditions. The method has the capability to entrap substantially higher amounts of hydrophilic solutes, compared to other passive-loading liposome preparation methods. These characteristics make this liposome type ideal for entrapment of labile substances, such as peptides, proteins, or DNA's (or other nucleotides or oligonucleotides), or in general biopharmaceuticals and sensitive drugs. In this chapter, all possible types of DRV liposomes (in respect to the encapsulated molecule characteristics and/or their applications in therapeutics) are introduced, and preparation methodologies (for each type) are described in detail.

Analyzing proteolytic stability and metabolic hotspots of therapeutic peptides in two rodent pulmonary fluids

Peptides and peptide drug conjugates are emerging modalities to treat pulmonary diseases. Peptides are susceptible to proteolytic cleavage. Expression levels of specific proteases in the lung can be significantly increased in disease state and may lead to exaggerated peptide proteolysis. To support optimization of peptides for inhaled administration, we have recently reported a streamlined high-throughput LC-HRMS protocol to determine enzymatic protease stability of peptides. This method has now been complemented with profiling of peptide metabolic stability in two respiratory fluids, a lung supernatant (lung S9) and a bronchioalveolar lavage fluid (BALF) taken from rats. We have tested a set of 28 peptides with high structural diversity, analyzed the whole data set for formed metabolites, and identified the differences of cleavage pattern in the two test fluids. Comparison of our experimental results and literature-derived cleavage site estimates based on e.g. MEROPS show significant differences for a number of peptides. This indicates the need for an experimental workflow using both protease panels and testing of metabolic stability in lung fluid (BALF) to guide peptide optimization and selection of peptides for inhaled in vivo PK/PD studies in our drug discovery projects.

New N- and C-modified RGD-hemorphins as potential biomedical application on Ti-surface materials: synthesis, characterization and antinociceptive activity

This manuscript presented the synthesis and characterization of two new N- and C-modified analogues of VV-hemorphin-7 containing RGD (Arg-Gly-Asp) residues as potential nociceptive agents and bioactive materials. It has been shown that the addition of one or two RGD sequences to natural VV-hemorphin-7 increases its effect on acute nociception, but the reduction of the inflammatory phase depends on the concentration of the peptide. The structure-property relationship of the new peptide derivatives was highlighted by electrochemical and FT-IR methods of analysis. Because of the proven bone-structural bonds of hydroxyapatite, the simultaneous deposition of peptide/hydroxyapatite on the surface of a titanium surface was investigated. The deposition was performed in a medium of gelatin solution containing dissolved amounts of peptide and hydroxyapatite using ultrasound. SEM-EDS analyzes confirmed the presence of a layer of the studied system.

Coupled folding-upon-binding of human tumor suppressor MIG6 to lung cancer EGFR kinase domain and molecular trimming/stapling of MIG6-derived β-hairpins to target the coupling event

Human epidermal growth factor receptor (EGFR) is involved in strong association with malignant proliferation, which has been shown to play a central role in the development and progression of non-small cell lung cancer and other solid tumors. The tumor-suppressor protein MIG6 is a negative regulator of EGFR kinase activity by binding at the activation interface of asymmetric dimer of EGFR kinase domain to disrupt EGFR dimerization and then inactivate the kinase. The protein adopts two discrete fragments 1 and 2 to directly interact with EGFR. It is revealed that the MIG6 fragment 2 is intrinsically disordered in free unbound state, but would fold into a well-structured β-hairpin when binding to EGFR, thus characterized by a so-called coupled folding-upon-binding process, which can be regarded as a compromise between favorable direct readout and unfavorable indirect readout. Here, a 23-mer F2P peptide was derived from MIG6 fragment 2, trimmed into a 17-mer tF2P peptide that contains the binding hotspot region of the fragment 2, and then constrained with an ordered hairpin conformation in free unbound state by disulfide stapling, finally resulting in a rationally stapled/trimmed stF2P peptide that largely minimizes the unfavorable indirect readout effect upon its binding to EGFR kinase domain, with affinity improved considerably upon the trimming and stapling/trimming. These rationally designed β-hairpin peptides may be further exploited as potent anti-lung cancer agents to target the activation event of EGFR dimerization.

Sequence driven interaction of amino acids in de-novo designed peptides determines c-Myc G-quadruplex unfolding inducing apoptosis in cancer cells

c-MYC proto-oncogene harbors a putative G-quadruplex structure (Pu27) at the NHEIII₁ domain, which can shuffle between transcriptional inhibitor quadruplex and transcriptionally active duplex. In cancer cells this quadruplex destabilization is preferred and NHEIII₁ domain assume a duplex topology thereby inducing c-MYC overexpression and tumorigenesis. Hence, the c-MYC quadruplex acts as an excellent target for anti-cancer therapy. Though researcher have tried to develop G-quadruplex targeted small molecules, work with G-quadruplex targeting peptides is very limited. Here we present a peptide that can bind to c-MYC quadruplex, destabilize the tetrad core, and permit the formation of a substantially different structure from the quartet core seen in the canonical G-quadruplexes. Such conformation potentially acted as a roadblock for transcription factors thereby reducing cMYC expression. This event sensitizes the cancer cell to activate apoptotic cascade via the c-MYC-VEGF-A-BCL2 axis. This study provides a detailed insight into the peptide-quadruplex interface that encourages better pharmacophore design to target dynamic quadruplex structure. We believe that our results will contribute to the development, characterization, and optimization of G-quadruplex binding peptides for potential clinical application.

A comparison of electrosprayed vs vortexed glycosaminoglycan-peptide nanoparticle platform for protection and improved delivery of therapeutic peptides

Therapeutic peptides capable of reducing inflammation via inhibition of the MAP kinase 2 pathway have the potential to reduce inflammation in atopic dermatitis by suppressing secretion of inflammatory cytokines by resident keratinocytes. One of the biggest hurdles to the use of therapeutic peptides, however, is their rapid degradation by intrinsic proteases and peptidases found in serum. Here we introduce a new nanoparticle technology that enhances and extends the bioactivity of a MAP KAP kinase 2 inhibitor peptide (MK2i) via electrostatic complexation with Dermatan sulfate (DS), a glycosaminoglycan, and explore their properties under various conditions. DS-MK2i nanoparticles can be made using electrospray ionization or sonication and vortexing with no stabilizing polymers or crosslinking. Average particle diameter, polydispersity index, and zeta potential were measured over a pH range of 2.5-11.5, in increments of 0.5, in water and at physiological ionic strength. Both particle types were shown to be shelf stable, robust, and behave differently in response to pH. They are also significantly more effective at suppressing cytokine secretion in inflamed, human keratinocytes than peptide alone in the presence of serum, providing a facile method of protecting peptides for therapeutic delivery in conditions such as atopic dermatitis, and abrogating the need for serum-starvation in in vitro testing.

Immunomodulatory IL-23 receptor antagonist peptide nanocoatings for implant soft tissue healing

OBJECTIVE

Peri-implantitis, caused by an inflammatory response to pathogens, is the leading cause of dental implant failure. Poor soft tissue healing surrounding implants - caused by inadequate surface properties - leads to infection, inflammation, and dysregulated keratinocyte and macrophage function. One activated inflammatory response, active around peri-implantitis compared to healthy sites, is the IL-23/IL-17A cytokine axis. Implant surfaces can be synthesized with peptide nanocoatings to present immunomodulatory motifs to target peri-implant keratinocytes to control macrophage polarization and regulate inflammatory axises toward enhancing soft tissue healing.

METHODS

We synthesized an IL-23 receptor (IL-23R) noncompetitive antagonist peptide nanocoating using silanization and evaluated keratinocyte secretome changes and macrophage polarization (M1-like "pro-inflammatory" vs. M2-like "pro-regenerative").

RESULTS

IL-23R antagonist peptide nanocoatings were successfully synthesized on titanium, to model dental implant surfaces, and compared to nonfunctional nanocoatings and non-coated titanium. IL-23R antagonist nanocoatings significantly decreased keratinocyte IL-23, and downstream IL-17A, expression compared to controls. This peptide noncompetitive antagonistic function was demonstrated under lipopolysaccharide stimulation. Large scale changes in keratinocyte secretome content, toward a pro-regenerative milieu, were observed from keratinocytes cultured on the IL-23R antagonist nanocoatings compared to controls. Conditioned medium collected from keratinocytes cultured on the IL-23R antagonist nanocoatings polarized macrophages toward a M2-like phenotype, based on increased CD163 and CD206 expression and reduced iNOS expression, compared to controls.

SIGNIFICANCE

Our results support development of IL-23R noncompetitive antagonist nanocoatings to reduce the pro-inflammatory IL-23/17A pathway and augment macrophage polarization toward a pro-regenerative phenotype. Immunomodulatory implant surface engineering may promote soft tissue healing and thereby reduce rates of peri-implantitis.

Molecular Imaging of HER2 Expression in Breast Cancer patients Using the [99mTc] Tc-Labeled Small Peptide

PURPOSE

The accurate determination of human epidermal growth factor receptor 2 (HER2) status can predict response to treatment with HER2-targeted therapy for HER2-positive breast cancer patients. [^99mTc]Tc-HYNIC-(Ser)₃-LTVPWY ([^99mTc]Tc-HYNIC-LY) is a small synthetic peptide molecule targeting of the HER2 receptor. This clinical study evaluated the pharmacokinetic, dosimetry, and efficacy of [^99mTc]Tc-HYNIC-LY for determining the HER2 status in primary breast cancer patients.

MATERIALS AND METHODS

In total, 24 women with suspected primary breast cancer received an intravenous injection of approximately 20 µg (∼740 MBq) of [^99mTc]Tc-HYNIC-LY. In the first 3 patients, blood levels of radioactivity were analyzed for pharmacokinetic evaluation and planar gamma camera imaging was conducted at 30 min and 1, 2, 4, and 24 hour after injection for dosimetry assessment. In the last 21 patients, planar imaging was performed at the baseline, as well as 1, 2, 3, and 4 hour, followed by single-photon emission computed tomography (SPECT) imaging after 4 hour to evaluate the tumor-targeting potential in primary lesions.

RESULTS

Injection of [^99mTc]Tc-HYNIC-LY was safe and well tolerated. Fast blood clearance provided high-contrast HER2 imaging within 1 to 4 hour. The highest absorbed radiation dose was found for kidneys (6.78E-03 ± 2.62E-04 mSv/MBq), followed by the heart (3.73E-03 ± 1.98E-04 mSv/MBq). The [^99mTc]Tc-HYNIC-LY peptide was able to detect HER2 status in primary tumors at an acceptable level.

CONCLUSION

The findings of this study indicated that [^99mTc]Tc-HYNIC-LY SPECT is safe and feasible for the identification of HER2-positive lesions in primary breast cancer patients, and may provide an accurate and non-invasive modality for guiding HER2 targeted therapy.

Peptide-drug conjugates (PDCs): a novel trend of research and development on targeted therapy, hype or hope?

Peptide-drug conjugates (PDCs) are the next generation of targeted therapeutics drug after antibody-drug conjugates (ADCs), with the core benefits of enhanced cellular permeability and improved drug selectivity. Two drugs are now approved for market by US Food and Drug Administration (FDA), and in the last two years, the pharmaceutical companies have been developing PDCs as targeted therapeutic candidates for cancer, coronavirus disease 2019 (COVID-19), metabolic diseases, and so on. The therapeutic benefits of PDCs are significant, but poor stability, low bioactivity, long research and development time, and slow clinical development process as therapeutic agents of PDC, how can we design PDCs more effectively and what is the future direction of PDCs? This review summarises the components and functions of PDCs for therapeutic, from drug target screening and PDC design improvement strategies to clinical applications to improve the permeability, targeting, and stability of the various components of PDCs. This holds great promise for the future of PDCs, such as bicyclic peptide‒toxin coupling or supramolecular nanostructures for peptide-conjugated drugs. The mode of drug delivery is determined according to the PDC design and current clinical trials are summarised. The way is shown for future PDC development.

A novel and low-toxic peptide DR3penA alleviates pulmonary fibrosis by regulating the MAPK/miR-23b-5p/AQP5 signaling axis

Pulmonary fibrosis (PF) is a pathological change caused by repeated injuries and repair dysfunction of the alveolar epithelium. Our previous study revealed that the residues Asn3 and Asn4 of peptide DR8 (DHNNPQIR-NH₂) could be modified to improve stability and antifibrotic activity, and the unnatural hydrophobic amino acids α-(4-pentenyl)-Ala and d-Ala were considered in this study. DR3penA (DHα-(4-pentenyl)-ANPQIR-NH₂) was verified to have a longer half-life in serum and to significantly inhibit oxidative damage, epithelial-mesenchymal transition (EMT) and fibrogenesis in vitro and in vivo. Moreover, DR3penA has a dosage advantage over pirfenidone through the conversion of drug bioavailability under different routes of administration. A mechanistic study revealed that DR3penA increased the expression of aquaporin 5 (AQP5) by inhibiting the upregulation of miR-23b-5p and the mitogen-activated protein kinase (MAPK) pathway, indicating that DR3penA may alleviate PF by regulating MAPK/miR-23b-5p/AQP5. Safety evaluation showed that DR3penA is a peptide drug without obvious toxicity or acute side effects and has significantly improved safety compared to DR8. Thus, our findings suggest that DR3penA, as a novel and low-toxic peptide, has the potential to be a leading compound for PF therapy, which provides a foundation for the development of peptide drugs for fibrosis-related diseases.

Peptide-modified carbon dot aggregates for ultrasensitive detection of lipopolysaccharide through aggregation-induced emission enhancement

This study fabricated yellow-emitting CDs (Y-CDs) by hydrothermal treatment of citric acid and urea and applied them as a fluorescence turn-on platform for sensitive and selective detection of lipopolysaccharide (LPS) based on the non-shifted AIEE of peptide-stabilized CD aggregates. The designed peptide (named K3) consisting of aggregation-active and LPS-recognition units triggered the aggregation of Y-CDs, switching on their fluorescence through the blue-shifted AIEE process. The formed K3-stabilized Y-CD aggregates (K3-YCDAs) specifically interacted with LPS at neutral pH, demonstrating that the sequence of the decorated peptide was highly connected with their selectivity and sensitivity. The K3-YCDAs provided a fast response time (within 5 min) to detect LPS with a quantification range of 0.5-100.0 nM and a limit of detection (LOD, signal-to-noise ratio of 3) of 300.0 pM. By integrating ultrafiltration membranes as a concentration device with K3-YCDAs as a sensing probe, the LOD for LPS was further reduced to 3.0 pM. The determination of picomolar levels of plasma LPS by the K3-YCDAs coupled to the centrifugation ultrafiltration was demonstrated to fall within the specificity range of clinical interest for sepsis patients. Also, the K3-YCDAs served as a fluorescent probe to selectively image and quantify E. coli cells. The distinct advantages of the K3-YCDAs for LPS include fast response time, wide linear range, low detection limit, and excellent selectivity compared to previously reported sensors.

Dental plaque-inspired versatile nanosystem for caries prevention and tooth restoration

Dental caries is one of the most prevalent human diseases resulting from tooth demineralization caused by acid production of bacteria plaque. It remains challenges for current practice to specifically identify, intervene and interrupt the development of caries while restoring defects. In this study, inspired by natural dental plaque, a stimuli-responsive multidrug delivery system (PMs@NaF-SAP) has been developed to prevent tooth decay and promote enamel restoration. Classic spherical core-shell structures of micelles dual-loaded with antibacterial and restorative agents are self-assembled into bacteria-responsive multidrug delivery system based on the pH-cleavable boronate ester bond, followed by conjugation with salivary-acquired peptide (SAP) to endow the nanoparticle with strong adhesion to tooth enamel. The constructed PMs@NaF-SAP specifically adheres to tooth, identifies cariogenic conditions and intelligently releases drugs at acidic pH, thereby providing antibacterial adhesion and cariogenic biofilm resistance, and restoring the microarchitecture and mechanical properties of demineralized teeth. Topical treatment with PMs@NaF-SAP effectively diminishes the onset and severity of caries without impacting oral microbiota diversity or surrounding mucosal tissues. These findings demonstrate this novel nanotherapy has potential as a promising biomedical application for caries prevention and tooth defect restoration while resisting biofilm-associated diseases in a controlled manner activated by pathological bacteria.

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Nanomaterials can adhere to tooth and target acidic biofilms specifically.

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Application of caries prevention and tooth defect restoration.

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Guidance for the innovation of the existing post-defect restoration strategies.

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The multidrug delivery system exerts antibacterial and restorative abilities on demand.

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Bacteria-responsive system resists biofilm-associated diseases in a controlled manner.

Plasma metabolites-based design of long-acting peptides and their anticancer evaluation

Antimicrobial peptides (AMPs) are generally small cationic amphipathic peptides, which are thought to be ideal antineoplastic agents, owing to their favorable selectivity to cancer cells and the ability to overcome drug-resistance. In this study, an anticancer AMP (Mastoparan (INLKALAALAKKIL-NH2)) was selected as the lead compound and a series of Mastoparan derivatives were designed. Preliminary studies verified that an analogue of Mastoparan, KM8 (KLLKINLKALAALAKKIL-NH2), exhibited prominent selective antitumor effects. Instead, it presents a significant defect of metabolic instability, with a half-life in plasma of only about 0.5 h. Metabolite profiling of KM8 was performed and indicated the structure ₉AL₁₀ in peptide sequence could be the fragile site for KM8. Thus, the Aib (unnatural amnio acid) was employed to substitute the ₉Ala residue in KM8, and generating a long-acting KM8 derivative, namely KM8-Aib. Further investigations revealed KM8-Aib possessed higher metabolic stability, more potent anticancer activity in vitro & in vivo, and lower toxicity. Therefore, KM8-Aib is suggested be a potential antimalignant agent that worthy of more in-depth study.

Neuroprotective effect of a novel brain-derived peptide, HIBDAP, against oxygen-glucose deprivation through inhibition of apoptosis in PC12 cells

BACKGROUND

The effect of a novel brain-derived peptide, hypoxic-ischemic brain damage associated peptide (HIBDAP), on apoptosis after oxygen-glucose deprivation (OGD) in PC12 cells was investigated.

METHODS

The HIBDAP sequence (HSQFIGYPITLFVEKER) was coupled with the carrier peptide of the transactivator of transcription (TAT) sequence (YGRKKRRQRRR). FITC-labelled TAT-HIBDAP was observed by fluorescence microscopy. After TAT-HIBDAP treatment and OGD treatment, the PC12 cell apoptosis rate was analysed using lactate dehydrogenase (LDH) leakage and Annexin V-fluorescein isothiocyanate (FITC) assays. Mitochondrial membrane potential (ΔΨm) was examined by fluorescence microscopy. Protein expression of apoptotic factors was examined by Western blotting.

RESULTS

FITC-labelled TAT-HIBDAP entered the PC12 cell nucleus. Compared with the OGD group, TAT-HIBDAP at low concentrations (1 µM, 5 µM, 10 µM) significantly reduced the apoptosis rate of PC12 cells (except at 20 µM); 5 µM TAT-HIBDAP had the most obvious effect. There were remarkable increases in ΔΨm at different concentrations (1 µM, 5 µM, 10 µM, 20 µM) of TAT-HIBDAP pretreatment, and 5 µM TAT-HIBDAP also had the most obvious effect. TAT-HIBDAP reversed the increased ratio of Bax/Bcl-2 and activation of Caspase-3 induced by OGD.

CONCLUSION

TAT-HIBDAP is resistant to OGD-induced PC12 cell apoptosis by regulating the Bax/Bcl-2/Caspase-3 pathway, which may provide a novel therapeutic strategy for neonatal HIBD.

Distributed functional-group polarizabilities in polypeptides and peptide clusters toward accurate prediction of electro-optical properties of biomacromolecules

CONTEXT

Aiming at accurately predicting electro-optical properties of biomolecules, this work presents distributed atomic and functional-group polarizability tensors for a series of polypeptides and peptide clusters constructed from glycine and its residuals. By partitioning the electron density using the quantum theory of atoms in molecules, we demonstrated a very good transferability of the group polarizabilities. We were able to identify and extract the most efficient functional groups capable of generating the largest electrical susceptibility in condensed phases. Both the isotropic polarizability and its anisotropy were used to understand the way functional groups act as sources of linear optical responses, how they interact with each other reinforcing the macroscopic optical behavior within the material, and how covalent bonds and non-covalent interactions, such as hydrogen bonds, determine refractive indices and birefringence. Particular attention is devoted to the peptide bonds as they provide links to build biomacromolecules or polymers. An adequate quantum-mechanical treatment of at least the first interaction sphere of a given functional group is required to properly describe the effects of mutual polarization, but we identified optimum cluster size and shape to better estimate polarizabilities and dipole moments of larger molecules or molecular aggregates from the knowledge of the electron density of a central molecule or amino acid residual that is representative of the bulk. The strategy outlined here is a fast yet effective tool for estimating the optical properties of proteins but could eventually find application in the rational design of optical organic materials as well.

METHODS

Electronic-structure calculations were performed on the Gaussin16 program at the DFT level using the CAMB3LYP functional and the double-ζ quality Dunning basis set aug-cc-pVDZ. Electron density partitioning followed the concepts of the Quantum Theory of Atoms and Molecules (QTAIM) and was performed using the AIMAll program. The locally developed Polaber routine was applied to calculate dipole moment vectors and polarizability tensors. It was amended to include the effects of the local field on a given central molecule by means of a modified Atom-Dipole Interaction Model (ADIM).

Pulmonary inflammation, oxidative stress, and fibrosis in a mouse model of cholestasis: the potential protective properties of the dipeptide carnosine

Cholestasis is a clinical complication that primarily influences the liver. However, it is well known that many other organs could be affected by cholestasis. Lung tissue is a major organ influenced during cholestasis. Cholestasis-induced lung injury could induce severe complications such as respiratory distress, serious pulmonary infections, and tissue fibrosis. Unfortunately, there is no specific pharmacological intervention against this complication. Several studies revealed that oxidative stress and inflammatory response play a role in cholestasis-induced lung injury. Carnosine (CARN) is a dipeptide found at high concentrations in different tissues of humans. CARN's antioxidant and antiinflammatory properties are repeatedly mentioned in various experimental models. This study aimed to assess the role of CARN on cholestasis-induced lung injury. Rats underwent bile duct ligation (BDL) to induce cholestasis. Broncho-alveolar lavage fluid (BALF) levels of inflammatory cells, pro-inflammatory cytokines, and immunoglobulin were monitored at scheduled intervals (7, 14, and 28 days after BDL). Moreover, lung tissue histopathological alterations and biomarkers of oxidative stress were evaluated. A significant increase in BALF inflammatory cells, TNF-α, IL-1β, IL-6, and immunoglobulin-G (IgG) was detected in the BALF of BDL rats. Moreover, lung tissue histopathological changes, collagen deposition, increased TGF-β, and elevated levels of oxidative stress biomarkers were evident in cholestatic animals. It was found that CARN (100 and 500 mg/kg, i.p.) significantly alleviated lung oxidative stress biomarkers, inflammatory response, tissue fibrosis, and histopathological alterations. These data indicate the potential protective properties of CARN in the management of cholestasis-induced pulmonary damage. The effects of CARN on inflammatory response and oxidative stress biomarkers seems to play a crucial role in its protective properties in the lung of cholestatic animals.

The impact of maceration on the 'Osteo-ome'; a pilot investigation

The bone proteome, i.e., the 'osteo-ome', is a rich source of information for forensic studies. There have been advances in the study of biomolecule biomarkers for age-at-death (AAD) and post-mortem interval (PMI) estimations, by looking at changes in protein abundance and post-translational modifications (PTMs) at the peptide level. However, the extent to which other post-mortem factors alter the proteome, including 'maceration' procedures adopted in human taphonomy facilities (HTFs) to clean bones for osteological collections, is poorly understood. This pilot study aimed to characterise the impact of these 'cleaning' methods for de-fleshing skeletons on bone biomolecules, and therefore, what further impact this may have on putative biomarkers in future investigations. Three specific maceration procedures, varying in submersion time (one week or two days) and water temperature (55 °C or 87 °C) were conducted on six bovid tibiae from three individual bovines; the proteome of fresh and macerated bones of each individual was compared. The maceration at 87 °C for two days had the greatest proteomic impact, decreasing protein relative abundances and inducing specific PTMs. Overall, these results suggest that routinely-employed maceration procedures are harsh, variable and potentially threaten the viability of discovering new forensic biomarkers in macerated skeletal remains. SIGNIFICANCE: For the first time, the application of bone proteomics in understanding maceration procedures was conducted to help address the risks for experimental confounding associated with this post-mortem cleaning technique. This pilot study demonstrates that recent advances in biomarker discovery for post-mortem interval and age-at-death estimation using bone proteomics has potential for confounding by differing and destructive bone-cleaning methods.

Bioinformatics evaluation of anticancer properties of GP63 protein-derived peptides on MMP2 protein of melanoma cancer

Background

GP63, also known as Leishmanolysin, is a multifunctional virulence factor abundant on the surface of Leishmania spp. small peptides with anticancer capabilities that are selective and toxic to cancer cells are known as anticancer peptides. We aimed to demonstrate the activity of GP63 and its anticancer properties on melanoma using a range of in silico tools and screening methods to identify predicted and designed anticancer peptides.

Methods

Various in silico modeling methodologies are used to establish the three-dimensional (3D) structure of GP63. Refinement and re-evaluation of the modeled structures and the built models' quality evaluated using the different docking used to find the interacting amino acids between MMP2 and GP63 and its anticancer peptides. AntiCP2.0 is used for screening anticancer peptides. 2D interaction plots of protein-ligand complexes evaluated by Protein-Ligand Interaction Profiler server. It is for the first time that used anticancer peptides of GP63 and the predicted and designed peptides.

Results

We used 3 peptides of GP63 based on the AntiCP 2.0 server with scores of 0.63, 0.53, and 0.49, and common peptides of GP63/MMP2 (continues peptide: mean the completely selected peptide after docking with non-anticancer effect, predicted with 0.58 score and designed peptides with 0.47 and 0.45 scores by AntiCP 2.0 server).

Conclusions

The antileishmanial and anticancer peptide research topics exemplify the multidisciplinary nature of peptide research. The advancement of therapeutics targeting cancer and/or Leishmania requires an interconnected research strategy shown in this work.

In silico peptide-based therapeutics against human colorectal cancer by the activation of TLR5 signaling pathways

OBJECTIVE

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in both men and women. Toll-like receptor 5 (TLR5), an autoimmune signaling receptor that plays a role in cancer, can be exploited for the suppression of human colon cancer. Salmonella flagellin protein, a novel agonist of TLR5 activating downstream signaling, could be a basis for designing anticancer peptides.

METHODS

The three-dimensional crystal structure of TLR5 (PDB ID: 3J0A, Resolution = 26.0 Å) was optimized using the AMBER force field in the YASARA suit. In silico enzymatic digestion tool, PeptideCutter, was used to identify peptides from Salmonella flagellin, an agonist against human TLR5. The 3D structure of the peptides was generated using PEP-FOLD3. These peptides were screened against human TLR5 using shape complementarity principles based on the binding affinity and interactions with the active residue of TLR5 monomer, and the selected peptides were further validated by molecular dynamic (MD) simulation.

RESULTS

In this study, we generated 42 peptides from Salmonella flagellin protein by in silico protein digestion. Then, based on a new hidden Markov model sub-optimal conformation sampling approach as well as the size of the fragments, we select 38 effective peptides from these 42 cleavages. These peptides were screened against the monomeric Xray structure of human TLR5 using shape complementarity principles. Based on the binding affinity and interactions with the active residue of TLR5 monomer (residues 294 and 366 of TLR5), nine top-scored peptides were selected for the initial molecular dynamic (MD) simulation. Among these peptides, Clv10, Clv17, and Clv28 showed high stability and less flexibility during MD simulation. A 1 μs MD simulation was performed on TLR5-Clv10, TLR-Clv17, and TLR5-Clv28 complexes to further analyze the stability, conformational changes, and binding mode (Clv10, Clv17, and Clv28). During this MD study, the peptides showed high salt bridges and ionic interactions with residue ASP294 and residue ASP366 throughout the simulation and remained in the concave of the human TLR5 monomer. The RMSD and Rg values showed that the peptide-protein complexes become stable after 200 ns of contraction and extraction.

CONCLUSION

These findings can facilitate the rational design of selected peptides as an agonist of TLR5, which have antitumor activity, suppress colorectal cancer tumors, and can be used as promising candidates and novel agonists of TLR5.

Intra-colony venom diversity contributes to maintaining eusociality in a cooperatively breeding ant

BACKGROUND

Eusociality is widely considered to evolve through kin selection, where the reproductive success of an individual's close relative is favored at the expense of its own. High genetic relatedness is thus considered a prerequisite for eusociality. While ants are textbook examples of eusocial animals, not all ants form colonies of closely related individuals. One such example is the ectatommine ant Rhytidoponera metallica, which predominantly forms queen-less colonies that have such a low intra-colony relatedness that they have been proposed to represent a transient, unstable form of eusociality. However, R. metallica is among the most abundant and widespread ants on the Australian continent. This apparent contradiction provides an example of how inclusive fitness may not by itself explain the maintenance of eusociality and raises the question of what other selective advantages maintain the eusocial lifestyle of this species.

RESULTS

We provide a comprehensive portrait of the venom of R. metallica and show that the colony-wide venom consists of an exceptionally high diversity of functionally distinct toxins for an ant. These toxins have evolved under strong positive selection, which is normally expected to reduce genetic variance. Yet, R. metallica exhibits remarkable intra-colony variation, with workers sharing only a relatively small proportion of toxins in their venoms. This variation is not due to the presence of chemical castes, but has a genetic foundation that is at least in part explained by toxin allelic diversity.

CONCLUSIONS

Taken together, our results suggest that the toxin diversity contained in R. metallica colonies may be maintained by a form of group selection that selects for colonies that can exploit more resources and defend against a wider range of predators. We propose that increased intra-colony genetic variance resulting from low kinship may itself provide a selective advantage in the form of an expanded pharmacological venom repertoire. These findings provide an example of how group selection on adaptive phenotypes may contribute to maintaining eusociality where a prerequisite for kin selection is diminished.

Mst1-mediated phosphorylation of Nur77 improves the endometrial receptivity in human and mice

BACKGROUND

Successful embryo implantation requires the attachment of a blastocyst to the receptive endometrial epithelium, which was disturbed in the women with recurrent implantation failure (RIF). Endometrial β3-integrin was the most important adhesion molecule contributing to endometrial receptivity in both humans and mice. Nur77 has been proven indispensable for fertility in mice, here we explore the role of Nur77 on embryo-epithelial adhesion and potential treatment to embryo implantation failure.

METHODS

The expression and location of Mst1 and Nur77 in endometrium from fertile women and RIF patients were examined by IHC, qRT-PCR and Western blotting. In vitro kinase assay following with LC-MS/MS were used to identify the phosphorylation site of Nur77 activated by Mst1. The phosphorylated Nur77 was detected by phos-tag SDS-PAGE assay and specific antibody against phospho-Nur77-Thr366. The effect of embryo-epithelium interaction was determined in the BeWo spheroid or mouse embryo adhesion assay, and delayed implantation mouse model. RNA-seq was used to explore the mechanism by which Nur77 derived peptide promotes endometrial receptivity.

FINDINGS

Endometrial Mammalian sterile 20 (STE20)-like kinase 1 (Mst1) expression level was decreased in the women with RIF than that in the fertile control group, while Mst1 activation in the epithelial cells promoted trophoblast-uterine epithelium adhesion. The effect of Nur77 mediated trophoblast-uterine epithelium adhesion was facilitated by active Mst1. Mechanistically, mst1 promotes the transcription activity of Nur77 by phosphorylating Nur77 at threonine 366 (T366), and consequently increased downstream target β3-integrin expression. Furthermore, a Nur77-derived peptide containing phosphorylated T366 markedly promoted mouse embryo attachment to Ishikawa cells ([4 (2-4)] vs [3 (2-4)]) and increased the embryo implantation rate (4 vs 1.4) in a delayed implantation mouse model by regulating integrin signalling. Finally, it is observed that the endometrial phospho-Nur77 (T366) level is decreased by 80% in the women with RIF.

INTERPRETATION

In addition to uncovering a potential regulatory mechanism of Mst1/Nur77/β3-integrin signal axis involved in the regulation of embryo-epithelium interaction, our finding provides a novel marker of endometrial receptivity and a potential therapeutic agent for embryo implantation failure.

FUNDING

National Key Research and Development Program of China (2018YFC1004400), the National Natural Science Foundation of China (82171653, 82271698, 82030040, 81971387 and 30900727), and National Institutes of Health grants (R01HL103869).

The potential of proteomics in the study of processed meat products

Proteomics is a field that has grown rapidly since its emergence in the mid-1990s, reaching many disciplines such as food technology. The application of proteomic techniques in the study of complex biological samples such as foods, specifically meat products, allows scientists to decipher the underlying cellular mechanisms behind different quality traits. Lately, much emphasis has been placed on the discovery of biomarkers that facilitate the prediction of biochemical transformations of the product and provide key information on parameters associated with traceability and food safety. This review study focuses on the contribution of proteomics in the improvement of processed meat products. Different techniques and strategies have recently been successfully carried out in the study of the proteome of these products that can help the development of foods with a higher sensory quality, while ensuring consumer safety through early detection of microbiological contamination and fraud. SIGNIFICANCE: The food industry and the academic world work together with the aim of responding to market demands, always seeking excellence. In particular, the meat industry has to face a series of challenges such as, achieving sensory attributes in accordance with the standards required by the consumer and maintaining a high level of safety and transparency, avoiding deliver adulterated and/or contaminated products. This review work exposes how the aforementioned challenges are attempted to be solved through proteomic technology, discussing the latest and most outstanding research in this regard, which undoubtedly contribute to improving the quality, in all the extension of the word, of meat products, providing relevant knowledge in the field of proteomic research.

Localized Instillation Enables In Vivo Screening of Targeting Peptides Using One-Bead One-Compound Technology

The One-Bead One-Compound (OBOC) library screening is an efficient technique for identifying targeting peptides. However, due to the relatively large bead size, it is challenging for the OBOC method to be applied for in vivo screening. Herein, we report an in vivo Localized Instillation Beads library (LIB) screening method to discover targeting peptides with the OBOC technique. Inspired by localized instillation, we constructed a cavity inside of a transplanted tumor of a mouse. Then, the OBOC heptapeptide library was injected and incubated inside the tumor cavity. After an efficient elution process, the retained beads were gathered, from which three MDA-MB-231 tumor-targeting heptapeptides were discovered. It was verified that the best peptide had 1.9-fold higher tumor accumulation than the commonly used targeting peptide RGD in vivo. Finally, two targeting proteins were discovered as potential targets of our targeting peptide to the MDA-MB-231 tumor. The in vivo LIB screening method expands the scope of OBOC peptide screening applications to discover targeting peptides in vivo feasibly and reliably.

Antimicrobial peptides with anticancer activity: Today status, trends and their computational design

Some antimicrobial peptides have been shown to be able to inhibit the proliferation of cancer cell lines. Various strategies for treating cancers with active peptides have been pursued. According to the reports, anticancer peptides are important therapeutic peptides, which can act through two distinct pathways: they either just create pores in the cell membrane, or they have a vital intracellular target. In this review, publications up to Sep. 2021 had extracted form Scopus and PubMed using "antimicrobial peptide" and "anticancer peptide" as keywords. In second step, "computational design" related publications extracted. Among publications, those have similar scopes were classified and selected based on mechanisms of action and application. In this review, the most recent advances in the field of antimicrobial peptides with anti-cancer activities have been summarized. Freely available webservers such as AntiCP, ACPP, iACP, iACP-GAEnsC, ACPred are discussed here. In conclusion, despite some limitations of ACPs such as production cost and challenges, short half-life and toxicity on normal cells, the beneficial properties of AMPs make some of them good therapeutic agents for cancer therapy. Towards designing novel ACPs, the computational methods have substantial position and have been used progressively, today.

Peptide mediated targeted delivery of gold nanoparticles into the demyelination site ameliorates myelin impairment and gliosis

Drug development for multiple sclerosis (MS) clinical management focuses on both neuroprotection and repair strategies, and is challenging due to low permeability of the blood-brain barrier, off-target distribution, and the need for high doses of drugs. The changes in the extracellular matrix have been documented in MS patients. It has been shown that the expression of nidogen-1 increases in MS lesions. Laminin forms a stable complex with nidogen-1 through a heptapeptide which was selected to target the lesion area in this study. Here we showed that the peptide binding was specific to the injured area following lysophosphatidylcholine (LPC) induced demyelination. In vivo data showed enhanced delivery of the peptide-functionalized gold nanoparticles (Pep-GNPs) to the lesion area. In addition, Pep-GNPs administration significantly enhanced myelin content and reduced astrocyte/microglia activation. Results demonstrated the possibility of using this peptide to target and treat lesions in patients suffering from MS.

Peptide mediated therapy in fibrosis: Mechanisms, advances and prospects

Fibrosis, a disease characterized by an excess accumulation of extracellular matrix components, could lead to organ failure and death, and is to blame for up to 45 % of all fatalities in developed nations. These disorders all share the common trait of an unchecked and increasing accumulation of fibrotic tissue in the affected organs, which leads to their malfunction and eventual failure, even if their underlying causes are highly diverse and, in some cases, remain unclear. Numerous studies have identified activated myofibroblasts as the common cellular elements ultimately responsible for the replacement of normal tissues with nonfunctional fibrotic tissue. The transforming growth factor-β pathway, for instance, plays a significant role in practically all kinds of fibrosis. However, there is no specific drug for the treatment of fibrosis, several medications with anti-hepatic fibrosis properties are still in the research and development stages. Peptide, which refers to a substance consisting of 2-50 amino acids, is characterized by structural diversity, low toxicity, biological activities, easy absorption, specific targeting, few side effects, and has been proven to be effective in anti-fibrosis. Here, we summarized various anti-fibrosis peptides in fibrosis including the liver, lungs, kidneys, and other organs. This review will provide a new insight into peptide mediated anti-fibrosis and is helpful to creation of antifibrotic medications.

Fast Protocols for Characterizing Antibody-Peptide Binding

Microarray assay formats gained popularity in the 1990s, first implemented in DNA-based arrays but later adopted for use with proteins, namely antibodies, peptides, low molecular weight (LMW) molecules, such as lipids, and even tissues. In nucleic acid-based affinity assays and arrays, but not in protein or peptide arrays, the specificity and affinity of complementary strand interactions can be deduced from or adjusted through modifications to the nucleotide sequence. Arrays of LMW molecules are characterized by largely uniform but low binding affinities. Multiplexed protein-based affinity assays, such as microarrays, might present an additional challenge due to heterogeneity of antigen properties and of their binding affinities. The use of peptides instead of proteins reduces physical heterogeneity of these reagents through either the widened peptide selection options or rational sequence engineering. However, rational engineering of binding affinities remains an unmet need, and peptide-binding affinities to the respective antipeptide antibodies could vary by orders of magnitude. Hence, multiplexing of such assays by using a microarray format and data analysis and interpretation requires some knowledge of their binding affinities. Low-throughput binding assays to characterize such peptide-antipeptide antibodies interactions are widely available, but scaling-up of traditional protein- and peptide-binding assays might present practical challenges. Here, we describe fast label-free practical approach especially suitable for estimating peptide-binding affinities. The method in question relies on commercially available biolayer interferometry-based equipment with a protocol which can be easily scaled-up, subject to user needs and equipment availability.

Study on anti-inflammatory effect of peptides-conjugated alumina nanoparticle on allergic rhinitis mice model

Allergic rhinitis (AR) is a common atopic problem in which immune response to the environmental factors leads to clinical symptoms. Helicobacter pylori neutrophil-activating protein (HP-NAP) as a peptide attenuates Th2 response and stimulates Th1 activation and mucus adhesion promoting protein (MapA) as a cell-surface protein binds to mucus. This study evaluated the effect of HP-NAP and MapA conjugated with alumina nanoparticle on AR. HP-NAP and HP-NAP with MapA were conjugated to alumina nanoparticle and two separate nanoparticles were produced. The AR mice were treated with these and HP-NAP in peptide form. The AR symptoms, gene expression of mucus, levels of IL-33 and IL-4, and total and ovalbumin (OVA)-specific IgE levels were evaluated. Nasal rubbing, sneezing, gene expression of mucus, and IL-33 and IL-4 levels, and OVA-specific and total IgE were decreased in three treated groups compared to AR, and there was a significant decrease in the symptoms in AR-H-M-A group (P < 0.05) when compared to the other treated groups. HP-NAP has a controlling effect on AR, and in nanoparticle-conjugated form it can strongly attach to the airway's mucus via MapA. Therefore, cooperation of HP-NAP-alumina with MapA can produce an effective and applicable treatment for AR.

Delivery of a peptide/microRNA blend via electrospun antimicrobial nanofibres for wound repair

Downregulation of microRNA-31 (miR-31) and microRNA-132 (miR-132) has been associated with delayed wound healing. Therefore, it was hypothesised that intracellular delivery of miR-31 and miR-132, both as individual and blend formulations, could promote tissue repair. The use of a blend could minimise potential toxicity and achieve synergistic effects, thus maximising the therapeutic effect. miR-31 and miR-132 were condensed with a 30-mer positively charged amphipathic peptide, RALA, to form nanocomplexes with an average size <200 nm and zeta-potential ≥10 designed to facilitate cellular internalisation. This enabled a fold increase in miR-31 and miR-132 expression of ≥100,000 in a murine fibroblast cell line (NCTC-929) and a skin human keratinocyte cell line (HaCaT), with intracellular delivery >70% for individual and blend formulations. Moreover, incubation with the nanocomplexes increased the migration of HaCaT cells ≥25% at 4 and 8 h post-incubation, as well as downregulation of EMP-1 and RASA1 and HB-EGF and RASA1, target genes for miR-31 and miR-132, respectively. Electrospinning was then employed to produce an alginate/polyvinyl alcohol/ciprofloxacin nanofibrous wound patch to facilitate the controlled delivery of the nanocomplexes. Nanofibres were crosslinked with glutaraldehyde to improve stability in aqueous solvents, and they were proven to be biocompatible with antimicrobial activity without cellular attachment to avoid injury upon removal. RALA/miR nanoparticles were incorporated to the nanofibrous wound dressing and in vivo wound healing studies using C57BL/6J mice demonstrated a >60% acceleration in the wound closure rate at Day 7 post-wounding, a ≥1.5 increase in epidermal thickness, and a ≥2 increase in blood vessel count with respect to commercial and untreated controls. Taken together, this data proves that delivery of RALA/miR-31 and RALA/miR-132 from an alginate/polyvinyl alcohol/ciprofloxacin nanofibrous wound dressing constitutes an advanced therapy for wound healing, by accelerating wound closure and improving healed tissue quality. STATEMENT OF SIGNIFICANCE: In this study, we report for the first time the use of the RALA peptide to deliver two miRNA 31 & 132 simultaneously from an electrospun patch. Both miRs have been shown to be downregulated in wounds and this study endeavoured to deliver a blend of the miRs from a nanofibre patch. Electrospinning was used to produce an alginate/polyvinyl alcohol/ciprofloxacin wound patch to enable controlled delivery of the miRs without cellular attachment to the wound with the added benefit of anti-microbial activity. Application of the nanofibre patch loaded with the blended RALA/miR nanoparticles demonstrated a synergistic effect with acceleration of wound closure rate, a significant increase in epidermal thickness and blood vessel count with respect to commercial and untreated controls.

Nanofibrillar peptide hydrogels for self-delivery of lonidamine and synergistic photodynamic therapy

The use of lonidamine (LND) in photodynamic therapy (PDT) provides a viable approach to develop low-dose PDT modules with high efficacy, for LND potentiates cytotoxicity of photosensitizers through dysregulation of mitochondrial function. Yet, the efficacy of LND is restricted by its low accumulation in cancer cells, especially in the mitochondrial compartments. To address the problem, we design an LND-derived self-assembling peptide molecule (LND-K) that dually targets integrin receptors and mitochondria of cancer cells. The targeted cellular delivery of LND-K gives higher efficacy in ablation of mitochondrial function in melanoma cells A375, as compared to free LND or the control molecule that lacks mitochondria-targeting moieties. To integrate LND-K in a typical PDT module, we develop a nanofibrillar hydrogel system through co-assembly of LND-K and TPPS₄, an anionic photosensitizer that forms tight electrostatic interactions with cationic residues of LND-K. Notably, hydrogel formulation of LND-K/TPPS₄ facilitates slow release of TPPS₄ over 14 days in vitro, and displays a longer retention time than aqueous solution of TPPS₄in vivo. By integrating a mitochondria-targeted molecule (LND-K) in a typical PDT module, we achieve synergistic killing of A375 cells with dual drugs, where LND-K not only serves as a chemotherapeutic drug, but also potentiates the cytotoxicities of TPPS₄ toward A375 cells in vitro and in vivo. The peptide-based drug self-delivery system promises the development of efficacious combination treatments against cancer, that integrate cell sensitization with existing anticancer modules (e.g., chemotherapy and PDT) for enhanced therapeutic efficacy. STATEMENT OF SIGNIFICANCE: This study reports the design and synthesis of a lonidamine (LND)-derived self-assembling peptide (LND-K) that dually targets integrin receptors and mitochondria of cancer cells. Under the precision guidance of a mitochondria-targeting sequence, LND-K-containing nanofibers target mitochondria and ablate mitochondrial functions. On one hand, the targeted delivery of LND-K reduces cell viabilities through a chemotherapy route; on the other hand, LND-K sensitizes cancer cells for subsequent PDT treatment with enhanced efficacy, which is mediated by induction of ROS, loss of mitochondrial membrane potential, and decrease of cellular ATP level. We believe that the design of mitochondria-targeted drug delivery systems with a self-assembling molecule provides a new approach to potentiate cytotoxicity of photosensitizers in a low-dose PDT module.

A peptide derived from the N-terminal of NS2A for the preparation of ZIKV NS2A recognition polyclonal antibody

Zika virus non-structural protein NS2A participates in viral replication, organization, and budding, as well as escaping host immunity. NS2A also involved in the induction of microcephaly by ZIKV. However, the above studies were mainly performed through NS2A with a tag due to the lack of available antibodies against NS2A. ZIKV NS2A is a multiplex transmembrane protein, which leads to difficulties in the preparation of its recognition antibodies, thus seriously affecting the study of ZIKV NS2A. In this study, we found that a peptide (GSTDHMDHFSLGVLC) derived from the N-terminal of ZIKV NS2A coupled to KLH induced antibodies recognizing ZIKV NS2A in rabbits. The purified polyclonal antibody recognized ZIKV NS2A in ZIKV-infected cells with high efficiency and specificity, as detected by western blot and immunofluorescence assay. Our study has important implications for the preparation of ZIKV NS2A antibodies and the in-depth study of ZIKV NS2A.

Modified CFBP-bFGF targeting to ischemic brain promoted the functional recovery of cerebral ischemia

The cerebral ischemia was one of the most common causes of disability and death worldwide. Basic fibroblast growth factor (bFGF) was reported to have neuroprotective function as well as promoting angiogenesis in the ischemic brain, but the targeting delivery of bFGF to ischemic brain was still difficult. In present study, a specific peptide was used to modify bFGF to construct recombinant CFBP-bFGF, and CFBP-bFGF could specifically deliver to ischemic brain through binding with the upregulated protein-connective tissue growth factor (CTGF). When CFBP-bFGF was used in rats with cerebral ischemia by intravenous injection, local concentration of the bFGF in ischemic brain was significantly increased. In addition, enhanced neurons survival, increased angiogenesis, decreased neuroinflammation were observed, that improved the motor functional recovery of cerebral ischemic injury. These results demonstrated that the targeting delivery of CFBP-bFGF would be a potential therapeutic approach for cerebral ischemia.

Drug conjugate-based anticancer therapy - Current status and perspectives

Drug conjugates are conjugates comprising a tumor-homing carrier tethered to a cytotoxic agent via a linker that are designed to deliver an ultra-toxic payload directly to the target cancer cells. This strategy has been successfully used to increase the therapeutic efficacy of cytotoxic agents and reduce their toxic side effects. Drug conjugates are being developed worldwide, with the potential to revolutionize current cancer treatment strategies. Antibody-drug conjugates (ADCs) have developed rapidly, and 14 of them have received market approval since the first approval event by the Food and Drug Administration in 2000. However, there are some limitations in the use of antibodies as carriers. Other classes of drug conjugates are emerging, such as targeted drugs conjugated with peptides (peptide-drug conjugates, PDCs) and polymers (polymer-drug conjugates, PolyDCs) with the remaining constructs similar to those of ADCs. These novel drug conjugates are gaining attention because they overcome the limitations of ADCs. This review summarizes the current state and advancements in knowledge regarding the design, constructs, and clinical efficacy of different drug conjugates.

Vascularized polypeptide hydrogel modulates macrophage polarization for wound healing

Wound repair involves a sophisticated process that includes angiogenesis, immunoregulation and collagen deposition. However, weak revascularization performance and the lack of biochemical cues to trigger immunomodulatory function currently limit biomaterial applications for skin regeneration and tissue engineering. Herein, we fabricate a new bioactive polypeptide hydrogel (QK-SF) constituted by silk fibroin (SF) and a vascular endothelial growth factor mimetic peptide KLTWQELYQLKYKGI (QK) for tissue regeneration by simultaneously promoting vascularization and macrophage polarization. Our results showed that this QK-SF hydrogel can be prepared via an easy manufacturing process, and exhibited good gel stability and low cytotoxicity to cultured human umbilical vein endothelial cells (HUVECs) via both live/dead and cell counting kit-8 assays. Importantly, this QK-SF hydrogel triggered macrophage polarization from M1 into M2, as exemplified by the enhanced expression of the M2 marker and decreased expression of the M1 marker in RAW264.7 cells. Furthermore, the QK-SF hydrogel showed high capacity for inducing endothelial growth, migration and angiogenesis, which were proved by increased expression of angiogenesis-related genes in HUVECs. Consistent with in vitro findings, in vivo data show that the QK-SF hydrogel promoted M2 polarization, keratinocyte differentiation, and collagen deposition in the mouse skin wound model in immunohistochemistry assay. Furthermore, this QK-SF hydrogel can reduce inflammation, induce angiogenesis and promote wound healing as exemplified by the increased vessel formation and decreased wound area in the mouse skin wound model. Altogether, these results indicate that the bioactive QK-SF hydrogel plays dual functional roles in promoting angiogenesis and immunoregulation for tissue regeneration. STATEMENT OF SIGNIFICANCE: The QK-SF hydrogel plays dual functional roles in promoting angiogenesis and immunoregulation for tissue repair and wound healing. The QK-SF hydrogel can be prepared via an easy manufacturing process, and exhibited good gel stability and low cytotoxicity to cultured HUVECs. The QK-SF hydrogel triggered macrophage polarization from M1 into M2. The QK-SF hydrogel showed high capacity for inducing endothelial growth, migration and angiogenesis. The QK-SF hydrogel promoted M2 polarization, keratinocyte differentiation, and collagen deposition.

Efficient Cloning of Inserts for Phage Display by Golden Gate Assembly

Phage display enables the discovery of high-affinity binders. In phage display, one commonly uses traditional cloning methods to insert DNA into the coding region of one of the five capsid proteins. Here we describe the use of a new vector with kanamycin resistance and BsaI sites for the utilization of Golden Gate cloning into the N-terminus of mature protein III. We also describe the successful pentavalent display of six different inserts: the AviD-tag, the Z-domain of protein A, the Myc-tag, the ALFA nanobody, the BC2 nanobody, and the Flag-tag.

The Assembly-Line Enzymology of Nonribosomal Peptide Biosynthesis

Peptide natural products constitute a major class of secondary metabolites produced by microorganisms (mostly bacteria and fungi). In the past several decades, researchers have gained extensive knowledge about nonribosomal peptides (NRPs) generated by ribosome-independent systems, namely, NRP synthetases (NRPSs). NRPSs are multifunctional enzymes consisting of semiautonomous domains that form a peptide backbone. Using a thiotemplate mechanism that employs assembly-line logic with multiple modules, NRPSs activate, tether, and modify amino acid building blocks, sequentially elongating the peptide chain before releasing the complete peptide. Adenylation, thiolation, condensation, and thioesterase domains play central roles in these reactions. This chapter focuses on the current understanding of these central domains in NRPS assembly-line enzymology.

Biomimetic chitosan-derived bifunctional lubricant with superior antibacterial and hydration lubrication performances

The lubrication deficiency in joints is a major cause of osteoarthritis. One of the most commonly used treatment means is to inject artificial lubricants, but there is a potential risk of infection during the injection process. Therefore, developing artificial lubricants with dual functions of friction-reduction and antibacterial is urgent. In this work, a novel polysaccharide-derived lubricant with simultaneous anti-bacteria and water-lubrication properties, called CS-MPC-N, is developed by grafting 2‑methacryloyloxylethyl phosphorylcholine (MPC) and nisin peptide onto backbone of chitosan (CS). Compared to the control CS, CS-MPC-N exhibits good lubrication and friction-reduction properties because of its excellent water solubility. Especially, CS-MPC-N shows low friction coefficient (0.03 ∼ 0.05) at the sliding interfaces of artificial joints materials or even natural articular cartilages. Moreover, CS-MPC-N can effectively inhibit the proliferation of Staphylococcus aureu, exhibiting excellent antibacterial effect. This kind of novel polysaccharide-derived lubricant is expected to be used in treating infectious arthritis.

Albumin-hitchhiking: Fostering the pharmacokinetics and anticancer therapeutics

Nanotherapeutics demonstrate poor accumulation in the tumor microenvironment due to poor extravasation and penetration into the tumor. Therapeutics such as oligonucleotides, peptides and other biologicals suffer from low systemic half-life and rapid degradation. Albumin-hitchhiking has emerged as an effective strategy to enhance tumor-specific accumulation of various therapeutics. Hitchhiking on serum albumin (SA) have shown to improve biological half-life of various therapeutics including nanocarriers (NCs), biologics, oligonucleotides, vaccines, etc. In addition, passive and active accumulation of SA-riding therapeutics in the tumor, site-specific drug release, and SA-mediated endosomal escape have improved the potential of various anticancer modalities such as chemo-, immune-, vaccine, and gene therapies. In this review, we have discussed the advantages of employing SA-hitchhiking in anticancer therapies. In addition, vaccine strategies employing inherent lymph-nodes accumulating property of albumin have been discussed. We have presented a clinical overview of SA-hitchhiked formulations along with possible bottlenecks for improved clinical outcomes. We have also discussed the role of physiologically based pharmacokinetics (PBPK) modelling for efficient characterization of anti-cancer nanotherapeutics.

Prediction of Peptide and TCR CDR3 Loops in Formation of Class I MHC-Peptide-TCR Complexes Using Molecular Models with Solvation

Formation of major histocompatibility (MHC)-peptide-T cell receptor (TCR) complexes is central to initiation of an adaptive immune response. These complexes form through initial stabilization of the MHC fold via binding of a short peptide, and subsequent interaction of the TCR to form a ternary complex, with contacts made predominantly through the complementarity-determining region (CDR) loops of the TCR. Stimulation of an immune response is central to cancer immunotherapy. This approach depends on identification of the appropriate combinations of MHC molecules, peptides, and TCRs to elicit an antitumor immune response. This prediction is a current challenge in computational biochemistry. In this chapter, we introduce a predictive method that involves generation of multiple peptides and TCR CDR 3 loop conformations, solvation of these conformers in the context of the MHC-peptide-TCR ternary complex, extraction of parameters from the generated complexes, and use of an AI model to evaluate the potential for the assembled ternary complex to support an immune response.

Structural modeling, energetic analysis and molecular design of a π-stacking system at the complex interface of pediatric respiratory syncytial virus nucleocapsid with the C-terminal peptide of phosphoprotein

Human respiratory syncytial virus (RSV) is a primary cause of lower respiratory tract infections and hospital visits during infancy and childhood. The RSV phosphoprotein (P) is a major polymerase cofactor that interacts with nucleoprotein (N) to promote the recognition of ribonucleoprotein complex (RNP) by viral RNA polymerase. The binding pocket of N protein is chemically diverse, in or around which a number of aromatic and charged amino acid residues are observed. Previously, a nonapeptide segment (P peptide, ²³³DNDLSLEDF²⁴¹) representing the C-terminal tail of P protein was identified to mediate the N-P interaction with a moderate affinity, in which the Phe241 at the end of P's C-terminus plays a critical role in the binding of P peptide to N protein. Here, we found that the side-chain aromatic phenyl moiety of P Phe241 residue can form short- and long-range cation-π interactions with N Arg132 and Arg150 residues, respectively, as well as T-shaped and parallel-displaced π-π stackings with N Tyr135 and His151 residues, respectively, which co-define a geometrically satisfactory π-stacking system at the complex interface of N protein with P peptide, thus largely stabilizing the complex architecture. The stacking effect was further optimized by systematically mutating the P Phe241 residue to other natural and non-natural aromatic amino acids with diverse chemical substitutions at the phenyl moiety to examine their structural and energetic effects on π-stacking system and on protein-peptide binding. The electron-donating mutations at the phenyl moiety of P Phe241 residue can effectively enhance the π-stacking system and then promote peptide binding, whereas the bulky and positively charged mutations would considerably impair the peptide potency by introducing steric hindrance and electrostatic repulsion. The [Tyr]P, [Thp]P and [Fph]P mutants were determined to have an increased affinity relative to wild-type P peptide, which could be used as self-inhibitory peptides to competitively disrupt the native interaction between N and P proteins.

Probing protein misfolding and dissociation with an infrared free-electron laser

Misfolding is observed in the mutant proteins that are causative for neurodegenerative disorders such as polyglutamine diseases. These proteins are prone to aggregate in the cytoplasm and nucleus of cells. To reproduce cells with the aggregated proteins, gene expression system is usually applied, in which the expression construct having the mutated DNA sequence of the interest is transfected into cells. The transfected DNA is finally converted into the mutant protein, which is gradually aggregated in the cells. In addition, a simple method to prepare the cells having aggregates inside has been recently applied. Peptides were first aggregated by incubating them in water. The aggregates are spontaneously taken up by cells because aggregated proteins generally transfer between cells. Peptides with different degrees of aggregation can be made by changing the incubation times and temperatures, which enables to examine contribution of aggregation to the toxicity to the recipient cells. Moreover, such cells can be used for therapeutic researches of diseases in which aggregates are involved. In this chapter, we show methods to induce aggregation of peptides. The functional analyses of the cells with aggregates are also described. Then, experimental dissociation of the aggregates produced using this method by mid infrared free electron laser irradiation and its theoretical support by molecular dynamics simulation are introduced as the therapeutic research for neurodegenerative disorders.

Scorpion venom peptide HsTx2 suppressed PTZ-induced seizures in mice via the circ_0001293/miR-8114/TGF-β2 axis

BACKGROUND

Due to the complexity of the mechanisms involved in epileptogenesis, the available antiseizure drugs (ASDs) do not meet clinical needs; hence, both the discovery of new ASDs and the elucidation of novel molecular mechanisms are very important.

METHODS

BALB/c mice were utilized to establish an epilepsy model induced by pentylenetetrazol (PTZ) administration. The peptide HsTx2 was administered for treatment. Primary astrocyte culture, immunofluorescence staining, RNA sequencing, identification and quantification of mouse circRNAs, cell transfection, bioinformatics and luciferase reporter analyses, enzyme-linked immunosorbent assay, RNA extraction and reverse transcription-quantitative PCR, Western blot and cell viability assays were used to explore the potential mechanism of HsTx2 via the circ_0001293/miR-8114/TGF-β2 axis.

RESULTS

The scorpion venom peptide HsTx2 showed an anti-epilepsy effect, reduced the inflammatory response, and improved the circular RNA circ_0001293 expression decrease caused by PTZ in the mouse brain. Mechanistically, in astrocytes, circ_0001293 acted as a sponge of endogenous microRNA-8114 (miR-8114), which targets transforming growth factor-beta 2 (TGF-β2). The knockdown of circ_0001293, overexpression of miR-8114, and downregulation of TGF-β2 all reversed the anti-inflammatory effects and the influence of HsTx2 on the MAPK and NF-κB signaling pathways in astrocytes. Moreover, both circ_0001293 knockdown and miR-8114 overexpression reversed the beneficial effects of HsTx2 on inflammation, epilepsy progression, and the MAPK and NF-κB signaling pathways in vivo.

CONCLUSIONS

HsTx2 suppressed PTZ-induced epilepsy by ameliorating inflammation in astrocytes via the circ_0001293/miR-8114/TGF-β2 axis. Our results emphasized that the use of exogenous peptide molecular probes as a novel type of ASD, as well as to explore the novel endogenous noncoding RNA-mediated mechanisms of epilepsy, might be a promising research area.

Nilabh Shastri - Towards understanding classical and non-classical MHC-I antigen processing and presentation

Major histocompatibility complex (MHC-I) peptide antigen processing and presentation has experienced a revived interest in the context of immuno oncology, immune surveillance escape by pathogen mutations and technical advances that accelerate vaccine design. This sheds new light on the discoveries made by Nilabh Shastri and colleagues that includes the characterisation of cryptic MHC-I peptide antigen epitopes derived from untranslated regions and the N-terminal trimming of peptide antigen precursors by the aminopeptidase ERAAP (ERAP1/2 / ARTS1/LRAP) in the endoplasmic reticulum (ER) prior to the complete assembly of MHC-I complexes and their subsequent exposure to the cell surface. These scientific findings have important implications for developing novel therapeutic approaches in immunotherapy and modern vaccine design.

Total synthesis of antiviral drug, nirmatrelvir (PF-07321332)

The emergence and rapid spread of coronavirus disease 2019 (COVID-19), a potentially fatal disease, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has swiftly led to public health crisis worldwide. Hence vaccines and antiviral therapeutics are an important part of the healthcare response to combat the ongoing threat by COVID-19. Here, we report an efficient synthesis of nirmatrelvir (PF-07321332), an orally active SARS-CoV-2 main protease inhibitor.

Rational design of stapled helical peptides as antidiabetic PPARγ antagonists to target coactivator site by decreasing unfavorable entropy penalty instead of increasing favorable enthalpy contribution

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor belonging to the nuclear hormone receptor and has been exploited as a well-established druggable target for the treatment of diabetes mellitus (DM). Traditionally, small-molecule compounds have been developed to attack at the ligand site and Ser273 phosphorylation site of PPARγ. In this study, we derived helical peptide segments from the LXXLL motif region of coactivator proteins as antidiabetic PPARγ antagonists, which were expected to competitively disrupt the native interaction between PPARγ and its cognate coactivators by rebinding at PPARγ coactivator site. Structural analysis, dynamics simulation and energetics dissection revealed that these peptides cannot be well folded into active helical structure when splitting from the protein context of their parent coactivators and exhibit a large flexibility and intrinsic disorder in the free state, which would, therefore, incur a considerable entropy penalty upon rebinding to PPARγ. Hydrocarbon stapling strategy was employed to constrain these free coactivator peptides into ordered helical conformation, thus largely minimizing unfavorable entropy penalty but having only a moderate effect on favorable enthalpy contribution. The computational findings were further substantiated by fluorescence-based assays; the binding affinity of three potent SRC1, NCoA6 and p300 coactivator peptides to PPARγ was observed to be improved by 7.2-fold, 4.2-fold and 5.7-fold upon the stapling, which were also measured to have an efficient competitive potency with their unstapled counterparts for PPARγ coactivator site, with CC₅₀ = 0.096, 0.12 and 0.18 μM, respectively.

BI 456906: Discovery and preclinical pharmacology of a novel GCGR/GLP-1R dual agonist with robust anti-obesity efficacy

OBJECTIVE

Obesity and its associated comorbidities represent a global health challenge with a need for well-tolerated, effective, and mechanistically diverse pharmaceutical interventions. Oxyntomodulin is a gut peptide that activates the glucagon receptor (GCGR) and glucagon-like peptide-1 receptor (GLP-1R) and reduces bodyweight by increasing energy expenditure and reducing energy intake in humans. Here we describe the pharmacological profile of the novel glucagon receptor (GCGR)/GLP-1 receptor (GLP-1R) dual agonist BI 456906.

METHODS

BI 456906 was characterized using cell-based in vitro assays to determine functional agonism. In vivo pharmacological studies were performed using acute and subchronic dosing regimens to demonstrate target engagement for the GCGR and GLP-1R, and weight lowering efficacy.

RESULTS

BI 456906 is a potent, acylated peptide containing a C18 fatty acid as a half-life extending principle to support once-weekly dosing in humans. Pharmacological doses of BI 456906 provided greater bodyweight reductions in mice compared with maximally effective doses of the GLP-1R agonist semaglutide. BI 456906's superior efficacy is the consequence of increased energy expenditure and reduced food intake. Engagement of both receptors in vivo was demonstrated via glucose tolerance, food intake, and gastric emptying tests for the GLP-1R, and liver nicotinamide N-methyltransferase mRNA expression and circulating biomarkers (amino acids, fibroblast growth factor-21) for the GCGR. The dual activity of BI 456906 at the GLP-1R and GCGR was supported using GLP-1R knockout and transgenic reporter mice, and an ex vivo bioactivity assay.

CONCLUSIONS

BI 456906 is a potent GCGR/GLP-1R dual agonist with robust anti-obesity efficacy achieved by increasing energy expenditure and decreasing food intake.

Late-Stage Modification of Oligopeptides by Nickel-Catalyzed Stereoselective Radical Addition to Dehydroalanine

Radical addition to dehydroalanine (Dha) represents an appealing, modular strategy to access non-canonical peptide analogues for drug discovery. Prior studies on radical addition to the Dha residue of peptides and proteins have demonstrated outstanding functional group compatibility, but the lack of stereoselectivity has limited the synthetic utility of this approach. Herein, we address this challenge by employing chiral nickel catalysts to control the stereoselectivity of radical addition to Dha on oligopeptides. The conditions accommodate a variety of primary and secondary electrophiles to introduce polyethylene glycol, biotin, halo-tag, and hydrophobic and hydrophilic side chains to the peptide. The reaction features catalyst control to largely override substrate-based control of stereochemical outcome for modification of short peptides. We anticipate that the discovery of chiral nickel complexes that confer catalyst control will allow rapid, late-stage modification of peptides featuring nonnatural sidechains.

Development of a cyclic-inverso AHSG/Fetuin A-based peptide for inhibition of calcification in osteoarthritis

OBJECTIVE

Ectopic calcification is an important contributor to chronic diseases, such as osteoarthritis. Currently, no effective therapies exist to counteract calcification. We developed peptides derived from the calcium binding domain of human Alpha-2-HS-Glycoprotein (AHSG/Fetuin A) to counteract calcification.

METHODS

A library of seven 30 amino acid (AA) long peptides, spanning the 118 AA Cystatin 1 domain of AHSG, were synthesized and evaluated in an in vitro calcium phosphate precipitation assay. The best performing peptide was modified (cyclic, retro-inverso and combinations thereof) and evaluated in cellular calcification models and the rat Medial Collateral Ligament Transection + Medial Meniscal Tear (MCLT + MMT) osteoarthritis model.

RESULTS

A cyclic peptide spanning AA 1-30 of mature AHSG showed clear inhibition of calcium phosphate precipitation in the nM-pM range that far exceeded the biological activity of the linear peptide variant or bovine Fetuin. Biochemical and electron microscopy analyses of calcium phosphate particles revealed a similar, but distinct, mode of action in comparison with bFetuin. A cyclic-inverso variant of the AHSG 1-30 peptide inhibited calcification of human articular chondrocytes, vascular smooth muscle cells and during osteogenic differentiation of bone marrow derived stromal cells. Lastly, we evaluated the effect of intra-articular injection of the cyclic-inverso AHSG 1-30 peptide in a rat osteoarthritis model. A significant improvement was found in histopathological osteoarthritis score and animal mobility. Serum levels of IFNγ were found to be lower in AHSG 1-30 peptide treated animals.

CONCLUSIONS

The cyclic-inverso AHSG 1-30 peptide directly inhibits the calcification process and holds the potential for future application in osteoarthritis.