Methicillin-resistant Staphylococcus pseudintermedius (MRSP), a zoonotic pathogen causing severe skin infection, has been shown to be combated by peptides with antimicrobial and anti-inflammatory properties. The phenol-soluble modulin beta (PSMβ) peptides that succeed where conventional drugs fall short are isolated from a unique strain (S. felis C4) found in feline skin.

Antimicrobial Peptides from Feline Skin

Once the PSMβ peptides were identified from the S. felis strain, LifeTein helped the scientists by synthesizing batches of the peptides to be tested against MRSP in mice. Results showed a significant reduction in necrotic skin injury from MRSP in mice treated with the S. felis extract. This was due to the antimicrobial peptides inhibiting translation and disrupting bacterial cell membranes, greatly reducing skin colonization of MRSP.

The group believes this study can re-establish the community of microbes on the skin that promote health. The results proved effective in vitro and in vivo when combatting MRSP. Overall, the discovery serves to represent a potential bacteriotherapeutic for both human and animal skin diseases like MRSP colonization and infection.

In a new study, Williams shows that the skin microbe Staphylococcus epidermidis can produce phenol-soluble modulins (PSMs) that will induce skin inflammation. These PSMs combine with cysteine proteases to promote skin disease.

1. SE PSMa:fMADVIAKIVEIVKGLIDQFTQK.
2. SE PSMd:fMSIVSTIIEVVKTIVDIVKKFKK.
3. SE PSMε:fMFIINLVKKVISFIKGLFGNNENE.
4. SE d-toxin:fMAADIISTIGDLVKWIIDTVNKFKK.
5. S.aureus PSMa3:fMEFVAKLFKFFKDLLGKFLGNN.
   f = N-terminal formylation

Williams metal., 2023, Cell Reports 42,113024 September 26, 2023 https://doi.org/10.1016/j.celrep.2023.113024

O’Neill AM, Worthing KA, Kulkarni N, et al. Antimicrobials from a feline commensal bacterium inhibit skin infection by drug-resistant S. pseudintermedius. Elife. 2021;10:e66793. Published 2021 Oct 19. doi:10.7554/eLife.66793

Nephrilin peptides have proven to have several beneficial systemic effects in rodent models of stress, burn, and sepsis by reducing present pro-inflammatory factors. Scientists in Sunnyvale, CA were keen on testing these nephrilin-class peptides on models of respiratory distress, applying their beneficial properties to rat scald-endotoxemia models. LifeTein synthesized specially designed peptides with Valproic acid covalently attached to the N-terminus to be tested on the scald-endotoxemia models.

Valporic Acid Enhances Nephrilin Peptides

Three peptides in total were synthesized for the group by LifeTein, Nmod3sN1v, Nmod3N1vA, and Nmod3N1vAS3, whose sequences can be seen in the figure. The latter two peptides differ from Nmod3sN1v in that they contain the tripeptide sequence d(AVD), since the tripeptide has shown to dramatically improve iron-binding in vitro. Nmod3N1vAS3 differs from Nmod3N1vA in that it contains a Y*LK motif (where Y* is phosphotyrosine). This motif was previously shown to inhibit STAT3 activation, a suspected role in lung inflammation pathology.

After treating the rat scald-endotoxemia models with the peptides, the group concluded that the Nmod3N1vA and Nmod3N1vAS3 peptides were superior than the Nmod3sN1v sequence in the following readings: protease-stability, biodistribution to lung tissue, amelioration of catabolism, early inflammation and insulin-resistance, activated lymph node dendritic / T-cells, breathing difficulty (by oximetry), lung edema, granulocyte count and IL1-beta in BAL fluid, systemic oxidative stress and kidney function. The group concluded that when compared to the original nephrilin peptide, these designs are at least ten times more potent by weight. The study showcases the potential these peptide designs hold for future drug development, especially in respiratory models and burn damage.

References: Desmond D. Mascarenhas, Puja Ravikumar, Edward P. Amento, N-modulin peptides attenuate respiratory distress in a scald-endotoxemia model, Burns Open, Volume 6, Issue 1, 2022, Pages 1-6, ISSN 2468-9122, https://doi.org/10.1016/j.burnso.2021.09.001.

Neurodegeneration in postmortem patients of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) has been correlated to distribution of dipeptide repeat proteins in the form of poly-GR. Scientists at the Erasmus University Medical Center Rotterdam have assessed the toxicity of poly-GR and found a possible suppression with the help of zebrafish, Trolox, and LifeTein’s own GR peptides and antibodies.

Trolox Suppresses Poly-GR Toxicity Identified by Antibodies

Using zebrafish as a model for C9FTD/ALS cases, scientists injected the embryos with RNA encoding ATG mediated codon-optimized 100xGR. These peptides provided by LifeTein were able to simulate the apoptosis in the brain and caused aberrant motor neuron morphology in the zebrafish embryos. Using LifeTein’s monoclonal antibody against poly-GR, the group was able to detect the poly-GR specifically in the brain.

The researchers’ study suggested inhibition of oxidative stress held the potential to suppress the poly-GR toxicity in these models. To apply this knowledge, the embryos were treated with Trolox, a known inhibitor of oxidative stress. Not only did this rescue the poly-GR toxicity, but it did so in vivo. This holds a promising future in treatment of C9FTD/ALS patients, indicating the possible role of oxidative stress implies the possible treatment by inhibiting the said stress.

References: Riemslagh FW, Verhagen RFM, van der Toorn EC, Smits DJ, Quint WH, van der Linde HC, van Ham TJ, Willemsen R. Reduction of oxidative stress suppresses poly-GR mediated toxicity in zebrafish embryos. Dis Model Mech. 2021 Oct 25:dmm.049092. doi: 10.1242/dmm.049092. Epub ahead of print. PMID: 34693978.

LifeTein’s cysteine-containing peptides helped researchers better understand the effect peptide physicochemical properties have on the pharmacokinetic profiles of the nanoparticles they are attached to. Better understanding and control of these effects is invaluable for future engineering design of many types of therapeutic nanomaterials, including for treatment of traumatic brain injuries (TBI).

Nanoparticles’ Physicochemical Properties Influenced by Peptides

Scientists at the University of California were keen on finding out what exact physicochemical properties in peptides affect the pharmacokinetics of nanoparticles designed for treating TBI. Nanoparticles are a convenient means of therapeutic drug delivery, as they can exhibit different pharmacokinetic profiles from the drug cargo in their core. This experiment analyzed how functionalizing the nanoparticles with PEG and an array of peptides with varying physicochemical properties, provided by LifeTein, contribute to the biodistribution in vivo, using a mouse model of TBI.

Results showed that the biodistribution of the modified nanoparticles varied mainly as a result of the charge of the peptides attached; basic peptides resulted in restricted distributions in the brain via convection-enhanced delivery (CED), as well as elevated off-target organ accumulation resulting in a decrease in brain accumulation when using systemic administration. In comparison, nanoparticles modified with acidic, zwitterionic, or neutral peptides demonstrated less restricted distribution in the brain via CED, and increased accumulation in injured vs. uninjured brain tissue after systemic administration.

This study suggests that the charge of peptides should be greatly taken into account when designing nanoparticles with peptide-modified surfaces. Peptides offer a great way to influence the biological interactions of nanoparticles, and understanding what physicochemical properties contribute to said influence will further advance the use of therapeutic nanoparticles in treatments like TBI.

Reference: Waggoner, L.E., Madias, M.I., Hurtado, A.A. et al. Pharmacokinetic Analysis of Peptide-Modified Nanoparticles with Engineered Physicochemical Properties in a Mouse Model of Traumatic Brain Injury. AAPS J 23, 100 (2021). https://doi.org/10.1208/s12248-021-00626-5

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The use of mobile microrobots offers a promising solution for targeted medical theranostic applications at normally inaccessible regions of the human body. Namely, the circulatory system is an ideal region for said applications, but blood flow can complicate both navigation inside the body and preservation of the microrobots.

Researchers have designed microrollers able to be controlled via magnetic propulsion and steering, able to maneuver against physiologically relevant blood flow effectively. The rollers are composed of a magnetically responsive half-side and a silica half-side for cargo loading and biochemical functionalities. Once navigated to cancerous cell monolayers, the rollers utilize surface-functionalized cell-specific antibodies as well as photocleavable linkers to release doxorubicin (DOX), and anticancer drug molecule, onto the target area.

Both the azide-DOX and o-nitrobenzyl photocleavable linker used by the team were provided by LifeTein, allowing the mircorollers to release the drug on demand via UV light exposure. This method of on demand delivery of the drug molecules combined with maneuverability of the microrollers designed by the researchers opens the door for development of next-generation microrobots for controlled navigation and cargo delivery in the circulatory system.

Reference: Alapan et al., Sci. Robot. 5, eaba5726 (2020) 20 May 2020

Phosphorylation plays a vital role in the regulation of cellular processes. Each phosphorylation pattern leads to different interactions and could result in distinct biological outcomes.

Single phosphorylated peptides are frequently used for research. However, multi-site phosphorylations play a more important role in protein-protein interaction, nuclear import and export, and many other functions.

The monophosphorylated peptides are much easier to synthesize than multiphosphorylated peptides using traditional methods. There are many reasons for the difficulties. First of all, the steric hindrance of the protected phosphorylated amino acids would decrease the coupling yield. In addition, the protecting group and cleavage conditions are very harsh for conventional methods.

LifeTein adapted the microwave-assisted heating technology for multiphosphorylated peptide synthesis. Our method increases the coupling efficiency with good yields. In our study, we utilized the optimized conditions for synthesizing peptides containing six phosphorylated amino acids.

LifeTein’s Innovative Synthetic Wasabi Receptor Toxin and Its Variants Propel Breakthrough in Chronic Pain Research

LifeTein’s groundbreaking work in synthetic peptides, including the Wasabi Receptor Toxin, its mutants, Biotinylated, and AlexaFluor-488 conjugated variants, has played a pivotal role in advancing our understanding of chronic pain mechanisms. This research supported the efforts of David Julius, who was awarded the Nobel Prize in Physiology or Medicine this year for his contributions.

Julius, along with his team at the University of California, San Francisco (UCSF), made a significant discovery involving a scorpion toxin that specifically targets the “wasabi receptor.” This receptor is an ion channel protein that triggers the intense sensations, such as the sinus-clearing effect of wasabi or the eye-watering pain from cutting onions.

The team’s research highlighted that the scorpion toxin, referred to as WaTx, activates the TRPA1 wasabi receptor, inducing a pain response to various irritants. Remarkably, WaTx is a novel type of cell-penetrating peptide that can enter cells directly across the plasma membrane without the need for channel proteins.

The implications of this discovery are vast, with potential applications in studying and treating chronic pain and inflammation. The unique properties of WaTx suggest it could be instrumental in developing new, non-opioid pain management therapies, as it induces pain and hypersensitivity without causing neurogenic inflammation.

David Julius’s research, particularly his exploration of receptors that detect temperature, has been recognized with the prestigious Nobel Prize in Physiology or Medicine 2021, underscoring the impact of his work on the medical and scientific community.

This research was documented in a study published by Lin King, J. V., Emrick, J. J., Kelly, M. J. S., Herzig, V., King, G. F., Medzihradszky, K. F., & Julius, D. (2019) in the journal Cell, where they discuss the mode-specific modulation of TRPA1 and its implications for pain management.

Histone H3K27M is a driving mutation in diffuse intrinsic pontine glioma (DIPG), a deadly pediatric brain tumor. The malignant and treatment-resistant brain tumor is a target for anti-cancer studies.

Through a global inhibition of PRC2 catalytic activity and displacement of H3K27me2/3, H3K27M reshapes the epigenome and promotes oncogenesis of DIPG. Consequentially, the histone modification H3K36me2, antagonistic to H3K27me2/3, is elevated. The relationship and role of H3K36me2 in H3K27M-DIPG was investigated by approaches to its upstream catalyzing enzymes, NSD1 and NSD2, the “writers”, and its downstream binding factors, LEDGF and HDGF2, the “readers”.

Tumor-promoting transcriptional programs in H3K27M-DIPG were found to be disrupted by loss of NSD1 and NSD2, thus impeding cellular proliferation and tumorigenesis.
Downstream, a chemically modified peptide mimicking endogenous H3K36me2 was found to dislodge LEDGF and HDGF2 from chromatin. As LEDGF and HDGF2 are the main readers mediating the protumorigenic effects downstream of NSD1/2-H3K36me2, dislodging them resulted in inhibition of H3K27M-DIPG proliferation.

In this study, the chemically modified peptides used were cell penetrating peptides purchased from LifeTein.

Reference: Sci. Adv. 2021 Jul 14; 7(29)

BRAF is the most frequently mutated kinase in human cancers and is one of the major effectors of oncogenic RAS. So BRAF is a target of interest for anti-cancer drug development.

Two FDA-approved inhibitors, dabrafenib and vemurafenib have been developed as inhibitors for BRAF. These ATP-competitive inhibitors potently inhibit the most common BRAF variant V600E. However, current BRAF inhibitors could induce drug resistance and paradoxical activation. New approaches and drug candidates are needed to disrupt the intact dimer interface of BRAF. The 10-mer peptide inhibitor braftide was designed using a computational approach to block RAF dimerization. It was found that the peptide inhibitor triggers selective protein degradation of BRAF and MEK through proteasome-mediated protein degradation in cells.

The combination of ATP competitive inhibitors and braftide eliminates paradoxical activation. This alternative strategy will improve the efficacy of current ATP-competitive inhibitors. The RAF dimer interface could be a promising therapeutic target.

Braftide is a 10-mer peptide TRHVNILLFM. Braftide disrupts BRAF dimers and inhibits BRAF kinase activity. Braftide causes degradation of BRAF leading to destabilized MAPK complexes. Braftide synergizes with ATP-competitive inhibitors like Dabrafenib to mitigate paradoxical MAPK activation and downregulate MAPK signaling.

In this study, the Braftide, Null-Braftide, TAT-PEGlinker-Braftide, and TAT peptides were purchased from LifeTein with TFA removal.

Reference: ACS Chem Biol. 2019 Jul 19; 14(7): 1471–1480.

LifeTein recently announced a significant accomplishment in peptide synthesis: the successful creation of the C subunit of the ATP synthase. This subunit is a highly hydrophobic peptide composed of 75 residues and plays a crucial role in cellular energy processes. Its structure is characterized by a transmembrane α-helical “hairpin” formation, typically assembled into oligomers of 8-16 units, varying with species, within the mitochondrial inner membrane.

The intriguing aspect of the C subunit is its spontaneous folding into a β-sheet conformation. The peptide’s far-UV circular dichroism (CD) spectrum analysis verified this unique structural formation. Intriguingly, the β-sheet conformation of the c subunit can lead to the formation of aggregates. The process of cross-β aggregate formation was carefully observed using the amyloid-binding dye Tiofavin T (TT). A pivotal discovery in this study was the identification of the essential role of Ca2+ in guiding the folding and self-assembly of the c subunits. This process influences the formation of oligomers, as opposed to fibrils.

Amyloidogenic peptides are known for their ability to form ion channels in lipid bilayers, and the human synthetic c subunit synthesized by LifeTein is no exception. This amyloidogenic peptide forms oligomers capable of creating ion-conducting pores in planar lipid bilayers. Interestingly, these oligomers present similarities in ion channel formation with other amyloids and synuclein, albeit with lower conductances compared to the canonical PTP. These misfolded forms of the c subunit, potentially toxic, could play a significant role in cellular pathophysiology, offering insights into various diseases.

This synthesis and study of the ATP synthase’s C subunit mark a notable advancement in peptide research, contributing valuable knowledge to the field of biochemistry and molecular biology.

For more detailed information, the original study can be accessed here: Nature Article on ATP Synthase C Subunit.

LifeTein’s work not only showcases the complexity of peptide synthesis but also opens avenues for further exploration in understanding protein structures and their implications in health and disease.

Reference: https://www.nature.com/articles/s41598-021-88157-z.pdf