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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