Peptide S2 Research Articles

Unveiling potent bioactive compounds and anti-angiogenic pathways in Gekko swinhonis Guenther for gastric cancer therapy

Ethnopharmacological relevanceGekko swinhonis Guenther, commonly referred to as Gecko in the following text, belongs to the genus Gekko within the family Gekko. Its dried whole body is a widely utilized traditional Chinese medicine, demonstrating significant efficacy in the treatment of gastrointestinal malignancies, particularly gastric cancer (GC). Nevertheless, the composition of the gecko is complex, necessitating further research into its active ingredients for the treatment of GC. Aim of the studyIsolation and characterization of the most active components in Gecko based on their anti-GC mechanisms of vascular endothelial cell inhibition and anti-neovascularization. Materials and methodsWe utilized the enzymatic hydrolysate of Geckos to investigate its effectiveness and underlying mechanisms. Initially, we assessed its efficacy in ectopic and in-situ GC tumor-bearing mouse models. Subsequently, we evaluated the effectiveness of peptides, aliphatics, and small molecules derived from Gecko using CCK-8 and 3D tumor spheroid assays. The activities of peptides S1-S4 were further examined through these experiments. Finally, we screened, synthesized, and investigated five potential peptides for their pharmacodynamics in the CCK-8 assay and in the in-situ GC model mice. ResultsThe Gecko can inhibit the formation of blood vessels in the tumor microenvironment, providing a localized treatment for GC. The peptide components significantly inhibit vascular endothelial cells and impede the formation of new blood vessels, with the S2 peptide sections (0.3 KD - 3 KD) demonstrating the most potent inhibitory activity against angiogenesis. One of the active peptides effectively suppresses the growth of in-situ GC in nude mice through angiogenesis inhibition and also modulates immunity, all while exhibiting excellent biosafety. ConclusionsWe have achieved a significant breakthrough in the local treatment of GC using Gecko. Through pharmacodynamic experiments and a systematic process of isolation and identification, we identified the most effective anti-GC ingredients of Gecko, based on their mechanisms of inhibiting vascular endothelial cells and promoting anti-angiogenesis. Furthermore, we synthesized a lead peptide that demonstrates promising therapeutic efficacy and safety.

S2 Peptide-Conjugated SARS-CoV-2 Virus-like Particles Provide Broad Protection against SARS-CoV-2 Variants of Concern.

Approved COVID-19 vaccines primarily induce neutralizing antibodies targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) protein. However, the emergence of variants of concern with RBD mutations poses challenges to vaccine efficacy. This study aimed to design a next-generation vaccine that provides broader protection against diverse coronaviruses, focusing on glycan-free S2 peptides as vaccine candidates to overcome the low immunogenicity of the S2 domain due to the N-linked glycans on the S antigen stalk, which can mask S2 antibody responses. Glycan-free S2 peptides were synthesized and attached to SARS-CoV-2 virus-like particles (VLPs) lacking the S antigen. Humoral and cellular immune responses were analyzed after the second booster immunization in BALB/c mice. Enzyme-linked immunosorbent assay revealed the reactivity of sera against SARS-CoV-2 variants, and pseudovirus neutralization assay confirmed neutralizing activities. Among the S2 peptide-conjugated VLPs, the S2.3 (N1135-K1157) and S2.5 (A1174-L1193) peptide-VLP conjugates effectively induced S2-specific serum immunoglobulins. These antisera showed high reactivity against SARS-CoV-2 variant S proteins and effectively inhibited pseudoviral infections. S2 peptide-conjugated VLPs activated SARS-CoV-2 VLP-specific T-cells. The SARS-CoV-2 vaccine incorporating conserved S2 peptides and CoV-2 VLPs shows promise as a universal vaccine capable of generating neutralizing antibodies and T-cell responses against SARS-CoV-2 variants.

Biochemical characterization and molecular modification of a zearalenone hydrolyzing enzyme Zhd11D from Phialophora attinorum

ZEN lactone hydrolase (ZHD) can hydrolyze zearalenone (ZEN) to less or non-toxic product, providing an environment-friendly way for food or feeds-containing ZENs detoxification. Here, a newly identified ZHD from Phialophora attinorum, annotated as Zhd11D, was characterized to exhibit highest activity against ZEN at pH 8.0 and 35 ℃ with a specific activity of 304.7 U/mg, which was far higher than most of the reported ZHDs. A nonspecific protein engineering method was introduced through fusing a segment of amphiphilic short peptide S1 at the N-terminus of Zhd11D, resulting in both improved activity (1.5-fold) and thermostability (2-fold at 40 ℃). Biochemical analysis demonstrated that self-aggregation caused by intermolecular interactions between S1 contributed to the improvement of the enzymatic properties of Zhd11D. Additionally, S1-Zhd11D showed a higher hydrolysis rate of ZEN than Zhd11D in peanut oil.

Synthesis, characterization, and wound healing properties of α/γ hybrid peptides.

The present work describes the synthesis, characterization, and wound healing properties of α/γ hybrid peptides: Boc-Phe-γ4 -Phe-Val-OMe (S1), Boc-D Phe-γ4 -Phe-Val-OMe (S2), Boc-Ala-γ4 -Phe-Val-OMe (S3), Boc-D Ala-γ4 -Phe-Val-OMe (S4), Boc-Leu-γ4 -Phe-Val-OMe (S5), and Boc-D Leu-γ4 -Phe-Val-OMe (S6). Peptides S1-S6 were screened against human keratinocytes (HaCaT) and RAW 264.7 cells. Among all, S1- and S2-treated cells exhibited high cell viability; S1 and S2 induced keratinocyte migration and inhibited the production of the cytokines IL-6 and TNF-α. In vivo results demonstrated that the hybrid peptides S1 and S2 accelerate wound healing in Wistar rats with 83% and 88% at 50 μg/ml, and 74% and 76% at 25 μg/ml, respectively.

Humoral and Cellular Immune Responses against SARS-CoV-2 after Third Dose BNT162b2 following Double-Dose Vaccination with BNT162b2 versus ChAdOx1 in Patients with Cancer.

Patients with cancer display reduced humoral responses after double-dose COVID-19 vaccination, whereas their cellular response is more comparable with that in healthy individuals. Recent studies demonstrated that a third vaccination dose boosts these immune responses, both in healthy people and patients with cancer. Because of the availability of many different COVID-19 vaccines, many people have been boosted with a different vaccine from the one used for double-dose vaccination. Data on such alternative vaccination schedules are scarce. This prospective study compares a third dose of BNT162b2 after double-dose BNT162b2 (homologous) versus ChAdOx1 (heterologous) vaccination in patients with cancer. A total of 442 subjects (315 patients and 127 healthy) received a third dose of BNT162b2 (230 homologous vs. 212 heterologous). Vaccine-induced adverse events (AE) were captured up to 7 days after vaccination. Humoral immunity was assessed by SARS-CoV-2 anti-S1 IgG antibody levels and SARS-CoV-2 50% neutralization titers (NT50) against Wuhan and BA.1 Omicron strains. Cellular immunity was examined by analyzing CD4+ and CD8+ T-cell responses against SARS-CoV-2-specific S1 and S2 peptides. Local AEs were more common after heterologous boosting. SARS-CoV-2 anti-S1 IgG antibody levels did not differ significantly between homologous and heterologous boosted subjects [GMT 1,755.90 BAU/mL (95% CI, 1,276.95-2,414.48) vs. 1,495.82 BAU/mL (95% CI, 1,131.48-1,977.46)]. However, homologous-boosted subjects show significantly higher NT50 values against BA.1 Omicron. Subjects receiving heterologous boosting demonstrated increased spike-specific CD8+ T cells, including higher IFNγ and TNFα levels. In patients with cancer who received double-dose ChAdOx1, a third heterologous dose of BNT162b2 was able to close the gap in antibody response.

Booster Vaccination Against SARS-CoV-2 Induces Potent Immune Responses in People With Human Immunodeficiency Virus.

People with human immunodeficiency virus (HIV) on antiretroviral therapy (ART) with good CD4 T-cell counts make effective immune responses following vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are few data on longer term responses and the impact of a booster dose. Adults with HIV were enrolled into a single arm open label study. Two doses of ChAdOx1 nCoV-19 were followed 12 months later by a third heterologous vaccine dose. Participants had undetectable viraemia on ART and CD4 counts >350 cells/µL. Immune responses to the ancestral strain and variants of concern were measured by anti-spike immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), MesoScale Discovery (MSD) anti-spike platform, ACE-2 inhibition, activation induced marker (AIM) assay, and T-cell proliferation. In total, 54 participants received 2 doses of ChAdOx1 nCoV-19. 43 received a third dose (42 with BNT162b2; 1 with mRNA-1273) 1 year after the first dose. After the third dose, total anti-SARS-CoV-2 spike IgG titers (MSD), ACE-2 inhibition, and IgG ELISA results were significantly higher compared to Day 182 titers (P < .0001 for all 3). SARS-CoV-2 specific CD4+ T-cell responses measured by AIM against SARS-CoV-2 S1 and S2 peptide pools were significantly increased after a third vaccine compared to 6 months after a first dose, with significant increases in proliferative CD4+ and CD8+ T-cell responses to SARS-CoV-2 S1 and S2 after boosting. Responses to Alpha, Beta, Gamma, and Delta variants were boosted, although to a lesser extent for Omicron. In PWH receiving a third vaccine dose, there were significant increases in B- and T-cell immunity, including to known variants of concern (VOCs).

1666P Lower virus neutralizing titers against SARS-CoV-2 Omicron strain after third dose BNT162b2 following primo-vaccination with ChAdOx1 versus BNT162b2 in cancer patients

Cancer patients display reduced humoral responses after initial COVID-19 vaccination. Although vaccination protects against severe COVID-19, T cell immunity is impaired in cancer patients. In recent studies, booster vaccines provide additional protection against SARS-CoV-2. However, more data is needed on different vaccination schedules. This prospective study compares BNT162b2 booster-vaccination after primo-vaccination with BNT162b2 (homologous) versus ChAdOx1 (heterologous) in cancer patients. 441 subjects (314 cancer patients and 127 healthy individuals) received a 3rd dose BNT162b2 (229 homologous vs 212 heterologous) 6-9 months after priming. Vaccine induced adverse events (AE) were captured up to 7 days after vaccination. Humoral immunity was assessed by SARS-CoV-2 anti-S1 IgG antibody levels and SARS-CoV-2 50% neutralization titers (NT50) for Wuhan and Omicron strains. Cellular immunity was examined by analyzing CD4 and CD8 T cell responses against SARS-CoV-2 specific S1 and S2 peptides. All assays were performed on blood samples collected 28 days after 3rd dose. Local AEs were more common after heterologous boosting, while no significant differences were seen for systemic AEs. SARS-CoV-2 anti-S1 IgG antibody levels did not differ significantly between homologous and heterologous boosted subjects (GMT 1755.90 BAU/ml [95% C) 1276.95-2414.48] vs 1495.82 BAU/ml (95% CI 1131.48-1977.46)). However, homologously boosted subjects show significantly higher NT50 values against Omicron. T cell responses were assessed by CD154 (CD40L) and CD137 expression on CD4 and CD8 T cells as general markers of antigen-specific stimulation. Here, no significant differences in T cell responses and cytokine levels of IFNγ, IL-2 and TNFα were observed between both boosting regimens. Homologous and heterologous boosted patients elicit similar SARS-CoV-2 anti-S1 IgG antibody levels. Yet, heterologous boosted subjects report more local AEs and homologous boosted subjects show significantly higher NT50 values against Omicron. No difference between T cell responses in heterologous and homologous boosted cohorts was observed.

Self-derived peptides from the SARS-CoV-2 spike glycoprotein disrupting shaping and stability of the homotrimer unit

The structural spike (S) protein from the SARS-CoV-2 β-coronavirus is shown to make different pre- and post-fusion conformations within its homotrimer unit. To support the ongoing novel vaccine design and development strategies, we report the structure-based design approach to develop self-derived S peptides. A dataset of crucial regions from the S protein were transformed into linear motifs that could act as the blockers or stabilizers for the S protein homotrimer unit. Among these distinct S peptides, the pep02 (537-QQFGRDIAD-545) and pep07 (821-RDLICAQKFNGLTVLPPLLTDE-842) were found making stable folded binding with the S protein (550–750 and 950–1050 regions). Upon inserting SARS-CoV-2 S variants in the peptide destabilized the complexed S protein structure, resulting an allosteric effect in different functional regions of the protein. Particularly, the molecular dynamics revealed that A544D mutation in the pep02 peptide induced instability for the complexed S protein, whereas the N943K variant from pep09 exhibited an opposite behavior. An increased protein-peptide binding affinity and the stable structural folding were observed in mutated systems, compared to that of the wild type systems. The presence of mutation has induced an “up” active conformation of the spike (RBD) domain, responsible for interacting the host cell receptor. Among the lower affinity peptide datasets (e.g., pep01), the S1 and S2 subunit in the protein formed an “open” conformation, whereas with higher affinity peptides (e.g., pep07) these domains gained a “closed” conformation. These findings propose that our designed self-derived S peptides could replace a single S protein monomer, blocking the homotrimer formation or inducing stability.

Immunodominant T-cell epitopes from the SARS-CoV-2 spike antigen reveal robust pre-existing T-cell immunity in unexposed individuals

The COVID-19 pandemic has revealed a range of disease phenotypes in infected patients with asymptomatic, mild, or severe clinical outcomes, but the mechanisms that determine such variable outcomes remain unresolved. In this study, we identified immunodominant CD8 T-cell epitopes in the spike antigen using a novel TCR-binding algorithm. The predicted epitopes induced robust T-cell activation in unexposed donors demonstrating pre-existing CD4 and CD8 T-cell immunity to SARS-CoV-2 antigen. The T-cell reactivity to the predicted epitopes was higher than the Spike-S1 and S2 peptide pools in the unexposed donors. A key finding of our study is that pre-existing T-cell immunity to SARS-CoV-2 is contributed by TCRs that recognize common viral antigens such as Influenza and CMV, even though the viral epitopes lack sequence identity to the SARS-CoV-2 epitopes. This finding is in contrast to multiple published studies in which pre-existing T-cell immunity is suggested to arise from shared epitopes between SARS-CoV-2 and other common cold-causing coronaviruses. However, our findings suggest that SARS-CoV-2 reactive T-cells are likely to be present in many individuals because of prior exposure to flu and CMV viruses.

A longitudinal study of antibody responses to selected host antigens in rheumatic fever and rheumatic heart disease.

Introduction. Group A streptococci can trigger autoimmune responses that lead to acute rheumatic fever (ARF) and rheumatic heart disease (RHD).Gap Statement. Some autoantibodies generated in ARF/RHD target antigens in the S2 subfragment region of cardiac myosin. However, little is known about the kinetics of these antibodies during the disease process.Aim. To determine the antibody responses over time in patients and healthy controls against host tissue proteins - cardiac myosin and peptides from its S2 subfragment, tropomyosin, laminin and keratin.Methodology. We used enzyme-linked immunosorbent assays (ELISA) to determine antibody responses in: (1) healthy controls; (2) patients with streptococcal pharyngitis; (3) patients with ARF with carditis and (4) patients with RHD on penicillin prophylaxis.Results. We observed significantly higher antibody responses against extracellular proteins - laminin and keratin in pharyngitis group, patients with ARF and patients with RHD when compared to healthy controls. The antibody responses against intracellular proteins - cardiac myosin and tropomyosin were elevated only in the group of patients with ARF with active carditis. While the reactivity to S2 peptides S2-1-3, 8-11, 14, 16-18, 21-22 and 32 was higher in patients with ARF, the reactivity in the RHD group was high only against S2-1, 9, 11, 12 when compared to healthy controls. The reactivity against S2 peptides reduced as the disease condition stabilized in the ARF group whereas the reactivity remained unaltered in the RHD group. By contrast antibodies against laminin and keratin persisted in patients with RHD.Conclusion. Our findings of antibody responses against host proteins support the multistep hypothesis in the development of rheumatic carditis. The differential kinetics of serum antibody responses against S2 peptides may have potential use as markers of ongoing cardiac damage that can be used to monitor patients with ARF/RHD.

Distinct antibody repertoires against endemic human coronaviruses in children and adults.

Four endemic human coronaviruses (HCoVs) are commonly associated with acute respiratory infection in humans. B cell responses to these “common cold” viruses remain incompletely understood. Here we report a comprehensive analysis of CoV-specific antibody repertoires in 231 children and 1168 adults using phage immunoprecipitation sequencing. Seroprevalence of antibodies against endemic HCoVs ranged between approximately 4% and 27% depending on the species and cohort. We identified at least 136 novel linear B cell epitopes. Antibody repertoires against endemic HCoVs were qualitatively different between children and adults in that anti-HCoV IgG specificities more frequently found among children targeted functionally important and structurally conserved regions of the spike, nucleocapsid, and matrix proteins. Moreover, antibody specificities targeting the highly conserved fusion peptide region and S2′ cleavage site of the spike protein were broadly cross-reactive with peptides of epidemic human and nonhuman coronaviruses. In contrast, an acidic tandem repeat in the N-terminal region of the Nsp3 subdomain of the HCoV-HKU1 polyprotein was the predominant target of antibody responses in adult donors. Our findings shed light on the dominant species-specific and pan-CoV target sites of human antibody responses to coronavirus infection, thereby providing important insights for the development of prophylactic or therapeutic monoclonal antibodies and vaccine design.

In-silico Study to elucidate corona Virus by plant phytoderivatives that hits as a fusion inhibitors targeting HR1 domain in spike protein which conformational Changes efficiently inhibit entry COVID-19

Introduction: COVID-19 could be a human beta corona virus that have potential source of severe widespread respiratory and asymptomatic multiple pathophysiological conditions and is belonging to the SARS and MERS β-corona viruses linage that have inflated mortality rates and acute potential of pandemic. The viral envelope surface spike glycoprotein (S) binding with host cell receptor angiotensin-converting enzyme 2 (ACE2) and conciliate fuse the virus particle inside the host cell membranes, promising spike protein substantially important to endocytosis and host species an involuntary orienting response. Methods: Within the present in-silico study, two plant bioactive compounds namely ALS-1 and ALS-2 (from Alangium salvifolium) were analyzed for his or her inhibitory role on fusion peptide region or S2 HR-1 domain and efficiently block virus entry into host cell by applying the molecular simulation, docking studies. Other parameters viz. determination of molecular interaction-based binding affinity values, protein-ligand interactions, Lipinski rule of 5, functional properties and biological activities for the above compounds were also calculated by employing the acceptable bioinformatics tools. Results: The results of docking analysis clearly showed that ALS-1 has highest binding affinity with trimeric Spike glycoprotein (-11.6 kcal/mole) and ALS-2 (-10.8 kcal/mole). Based on protein interaction analysis both phytoderivatives bind HR-1 (fusion peptide) domain. Other parametric results showed good absorption activity and not violated Lipinski score of drug-likeness. Conclusion: Therefore studied plant derivatives may have the potential to play a big role as 2019 n-CoV fusion peptide inhibitor, revealing influential inhibitory activity against S-participated endocytosis and 2019 n-CoV viral infection, suggesting further optimizations (3-DQASR) and pharmaceutical development of both derivatives, respectively, to stop and treat novel COVID-19 infection.

Peptide derivatives of dermaseptin S4 in fresh bovine semen for bacterial contamination control: Physicochemical and structural characterization, antibacterial potency, and effects on red blood and sperm cells.

The objectives of this study were to examine the physicochemical and structural properties of peptide derivatives of dermaseptin S4, investigate their detrimental effects on red blood and sperm cells and ascertain their antibacterial potency to control bacterial contaminants in fresh bovine semen. The dermaseptin S4 peptide derivatives used in this study were K4S4, S4(5-28), S4(5-28)a, K20S4(5-28), K4S4(1-16)a, K4S4(1-15)a and K4S4(1-15). Peptides K4S4, S4(5-28)a, K20S4(5-28), K4S4(1-15)a and K4S4(1-16)a, with a higher positive charge, were the most potent against the bacterial strains tested, with the lowest minimum inhibitory concentration (MIC), whereas S4(5-28) and K4S4(1-15), with a lower positive charge, showed the highest MIC (p<.01). Haemolysis percentage depended on peptide concentration (p<.01). The K4S4 was the most powerful haemolytic peptide, showing the highest haemolysis percentage at all peptide concentrations (p<.01). In contrast, S4(5-28), S4(5-28)a, K20S4(5-28) and K4S4(1-15) were not able to produce 50% cell lysis up to 100µM (p<.01). All peptides reduced sperm motility in a dose-dependent manner when used in concentrations from 16 to 64μM (p<.01). The highest reduction was seen due to K4S4 activity, and the lowest reductions of sperm motility were observed due to K4S4(1-16)a and K4S4(1-15)a activity (p<.01). Hence, we can conclude that K4S4(1-16)a and K4S4(1-15)a at a concentration of approximately 15µM are the most promising peptides as antibacterial agents in fresh bovine semen, because at this concentration, they showed the most potent antibacterial activity against evaluated strains without significant effects on haemolysis or a reduction in sperm motility.

Affinity Isolation of Defined Genomic Fragments Cleaved by Nuclease S1-based Artificial Restriction DNA Cutter.

The human genome is highly susceptible to various modifications, lesions, and damage. To analyze lesions and proteins bound to a defined region of the human genome, the genome should be fragmented at desired sites and the region of interest should be isolated. The few available methods for isolating a desired region of the human genome have serious drawbacks and can only be applied to specific sequences or require tedious experimental procedures. We have recently developed a novel method to isolate a desired fragment of the genome released by site-specific scission of DNA using a pair of pseudo-complementary peptide nucleic acids (pcPNAs) and S1 nuclease. When conjugated to biotin, one of the pcPNAs can be used to affinity purify the cleavage product. Here we report a detailed protocol to isolate defined kilobase-length DNA fragments that can be applied to plasmid or genomic DNA and is not limited by sequence. © 2019 by John Wiley & Sons, Inc.

Role of β-naphthylalanine end-tags in the enhancement of antiendotoxin activities: Solution structure of the antimicrobial peptide S1-Nal-Nal in complex with lipopolysaccharide

Lipopolysaccharide (LPS, endotoxin) is the major component of Gram-negative bacterial outer surface membrane. LPS released from bacteria into bloodstream during infection may cause serious unwanted stimulation of host's immune system and lead to septic shock of the patient. Recently, we have developed a strategy to increase salt resistance and LPS neutralization of short antimicrobial peptides by adding β-naphthylalanine end-tags to their termini. Herein, correlations between membrane immersion depth, orientation, and antiendotoxin activities of the antimicrobial peptides S1 and S1-Nal-Nal have been investigated via solution structure, paramagnetic resonance enhancement, and saturation transfer difference NMR studies. Unlike the parent peptide S1, S1-Nal-Nal rotated its two terminal β-naphthylalanine residues into the hydrophobic lipid A motif of LPS micelles. The LPS-induced inflammation may then be prohibited by the blocked lipid A motif.

Peptide functionalized targeting liposomes: for nanoscale drug delivery towards angiogenesis.

A novel affinity peptide S1 (LIDHEWKENYFPLSF) was screened out via a "one bead one compound" (OBOC) approach on a microarray device. It was identified that S1 could specifically recognize and bind to vascular endothelial growth factor receptor 2 (VEGFR2), which is an angiogenesis biomarker. Moreover, S1-functionalized liposomes (S1-LS) could achieve efficient nanoscale drug delivery under the conditions of VEGFR2-overexpression in vitro and in vivo. It was demonstrated that S1-LS would be a promising VEGFR2-targeting drug delivery system.

A novel stearic acid-modified hirudin peptidomimetic with improved pharmacokinetic properties and anticoagulant activity.

A novel hirudin isoform 3 mimetic peptide, named peptide S2, has been prepared by introduction of a stearic acid modification. Peptide S2 exhibited superior inhibitory activity to hirulog-1 (Bivariludin) and showed significantly higher anticoagulant potency in vivo. Peptide S2 elevated the thrombin time, prothrombin time and activated partial thromboplastin time of rat and human plasma more efficiently than hirulog-1 and the unmodified form of peptide S2 (peptide 1). Furthermore, peptide S2 inhibited arterial thrombosis and inferior vena cava in rat model 8 h after administration, and was 10-fold more potent than hirulog-1 300 min after administration of 0.1 μmol/kg peptide. The enhanced antithrombotic activity could be attributed to its long half-life (T1/2 = 212.2 ± 58.4 min), which was 13.1 and 14.7-fold longer than those of hirulog-1 (T1/2 = 15.1 ± 1.3 min) and peptide 1 (T1/2 = 13.5 ± 2.6 min), respectively. Further enzymatic degradation and binding assay with human serum albumin (HSA) demonstrated that the longer duration time should be originated from the slowing of trypsin or thrombin–mediated degradation, as well as its binding to HSA. The improved pharmacokinetic properties observed for peptide S2 has made it a promising therapeutic agent for the treatment of thrombi-related diseases.

Ultrashort Antimicrobial Peptides with Antiendotoxin Properties.

Release of lipopolysaccharide (LPS) (endotoxin) from bacteria into the bloodstream may cause serious unwanted stimulation of the host immune system. Some but not all antimicrobial peptides can neutralize LPS-stimulated proinflammatory responses. Salt resistance and serum stability of short antimicrobial peptides can be boosted by adding β-naphthylalanine to their termini. Herein, significant antiendotoxin effects were observed in vitro and in vivo with the β-naphthylalanine end-tagged variants of the short antimicrobial peptides S1 and KWWK.

Cell Cycle Regulation of Microtubule Interactomes: Multi-layered Regulation Is Critical for the Interphase/Mitosis Transition

Microtubules dramatically change their dynamics and organization at the entry into mitosis. Although this change is mediated by microtubule-associated proteins (MAPs), how MAPs themselves are regulated is not well understood. Here we used an integrated multi-level approach to establish the framework and biological significance of MAP regulation critical for the interphase/mitosis transition. Firstly, we applied quantitative proteomics to determine global cell cycle changes in the profiles of MAPs in human and Drosophila cells. This uncovered a wide range of cell cycle regulations of MAPs previously unidentified. Secondly, systematic studies of human kinesins highlighted an overlooked aspect of kinesins: most mitotic kinesins suppress their affinity to microtubules or reduce their protein levels in interphase in combination with nuclear localization. Thirdly, in-depth analysis of a novel Drosophila MAP (Mink) revealed that the suppression of the microtubule affinity of this mitotic MAP in combination with nuclear localization is essential for microtubule organization in interphase, and phosphorylation of Mink is needed for kinetochore-microtubule attachment in mitosis. Thus, this first comprehensive analysis of MAP regulation for the interphase/mitosis transition advances our understanding of kinesin biology and reveals the prevalence and importance of multi-layered MAP regulation.

Mitochondrial targeting functional peptides as potential devices for the mitochondrial delivery of a DF-MITO-Porter

To achieve mitochondrial therapy, we previously reported on the use of an octaarginine (R8) modified Dual Function (DF)-MITO-Porter for delivering molecules to mitochondria in living cells. In this study, using isolated mitochondria, homogenates and living cells, we evaluated the utility of mitochondrial targeting functional peptides as a ligand for delivering carriers. The S2 peptide modified carrier showed a high mitochondrial targeting activity in homogenates and living cells. In addition, the S2 peptide had a lower cell toxicity compared to R8 modified liposomes. The S2 peptide represents a potentially useful moiety for constructing an efficient and safe mitochondrial delivery system.