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Computational protein design is becoming increasingly helpful in the development of new protein therapeutics with enhanced efficacy, specificity, and minimal side effects, for precise modulation of biological pathways. In vascular biology, the interaction between vascular endothelial growth factor A (VEGFA) and its receptors (VEGFR1-R3) is a pivotal process underlying blood vessel growth. Dysregulation of this pathway contributes to diseases such as cancer and diabetic retinopathy. Existing VEGFA inhibitors are effective but have limitations, driving interest in peptide-based therapeutics. Peptide inhibitors offer advantages, including reduced toxicity, improved formulation flexibility, and enhanced stability. This study leverages computational tools, particularly ProteinMPNN and Rosetta, to design optimized peptide-based VEGFA inhibitors. Building on the existing peptide templates mini-Z-1 and Z-1-2, new sequences were computationally predicted and experimentally validated. A novel peptide with improved affinity (KD = 6.2 µM) compared to mini-Z-1 (KD = 9.3 µM) was found, requiring only one round of design and testing. The integration of ProteinMPNN and Rosetta enabled a rapid and cost-effective pipeline for designing potent VEGFA inhibitors, underscoring the potential of computational peptide design in developing next-generation therapeutics targeting angiogenesis-dependent diseases.

Background: Schistosomes are highly efficient evaders of human immunity, as evident by their ability to survive in human blood for years. How they protect themselves against the constant attack by a key element of innate immunity, the complement system, has remained unclear. In this study, new light is shed on the interaction between distinct life-cycle stages of Schistosoma mansoni and the human complement system., Results: We demonstrate that schistosomula, the young stage assumed immediately after cercaria penetration of the skin, are extremely vulnerable towards complement-mediated killing as only 10-20% survive. The survival rate increases to 70% already within 30 minutes and reaches close to 100% within two hours. Pathway-specific complement inhibitors revealed the alternative pathway of complement activation as the main contributor to killing and damage of the schistosomula. Moreover, the complement regulator factor H is recruited by the schistosomula in this early stage to evade killing. Surviving parasites appear fully viable despite the ongoing complement attack, as demonstrated by the deposition of C3 fragments. However, when exposed to the widely used schistocidal drug praziquantel, the vulnerability of 24 h-old schistosomula towards complement-mediated killing is notably increased; no such effect was observed for mefloquine or oxamniquine. Similar to the younger life-cycle stages, adult worms remain under complement attack. C3 fragments were found all over the outer surface (tegument), deposited mostly on the ridges and not on the tubercles., Conclusion: The recruitment of factor H merits more detailed studies that pinpoint the molecules involved and elucidate the novel possibilities to intercept the uncovered immune evasion therapeutically. That praziquantel and complement work in synergy is surprising and may in the future result in enhanced understanding of the drug's mechanism of action., Competing Interests: CS is an inventor of patent applications that describes the use of engineered complement inhibitors for therapeutic applications. He has received honoraria for speaking at symposia as well as research funding from the pharmaceutical industry. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 van Beek, Jeanguenat, Häberli, Pouw, Lamers, Pál, Gál, Schmidt, Ricklin and Keiser.)

Coagulation factor XII (FXII) conveys various functions as an active protease that promotes thrombosis and inflammation, and as a zymogen via surface receptors like urokinase-type plasminogen activator receptor (uPAR). While plasma levels of FXII are increased in diabetes mellitus and diabetic kidney disease (DKD), a pathogenic role of FXII in DKD remains unknown. Here we show that FXII is locally expressed in kidney tubular cells and that urinary FXII correlates with kidney dysfunction in DKD patients. F12-deficient mice (F12 -/- ) are protected from hyperglycemia-induced kidney injury. Mechanistically, FXII interacts with uPAR on tubular cells promoting integrin β1-dependent signaling. This signaling axis induces oxidative stress, persistent DNA damage and senescence. Blocking uPAR or integrin β1 ameliorates FXII-induced tubular cell injury. Our findings demonstrate that FXII-uPAR-integrin β1 signaling on tubular cells drives senescence. These findings imply previously undescribed diagnostic and therapeutic approaches to detect or treat DKD and possibly other senescence-associated diseases., (© 2024. The Author(s).)

Glomerular-tubular crosstalk within the kidney has been proposed, but the paracrine signals enabling this remain largely unknown. The cold-shock protein Y-box binding protein 1 (YBX1) is known to regulate inflammation and kidney diseases but its role in podocytes remains undetermined. Therefore, we analyzed mice with podocyte specific Ybx1 deletion (Ybx1 ΔPod ). Albuminuria was increased in unchallenged Ybx1 ΔPod mice, which surprisingly was associated with reduced glomerular, but enhanced tubular damage. Tubular toll-like receptor 4 (TLR4) expression, node-like receptor protein 3 (NLRP3) inflammasome activation and kidney inflammatory cell infiltrates were all increased in Ybx1 ΔPod mice. In vitro, extracellular YBX1 inhibited NLRP3 inflammasome activation in tubular cells. Co-immunoprecipitation, immunohistochemical analyses, microscale cell-free thermophoresis assays, and blunting of the YBX1-mediated TLR4-inhibition by a unique YBX1-derived decapeptide suggests a direct interaction of YBX1 and TLR4. Since YBX1 can be secreted upon post-translational acetylation, we hypothesized that YBX1 secreted from podocytes can inhibit TLR4 signaling in tubular cells. Indeed, mice expressing a non-secreted YBX1 variant specifically in podocytes (Ybx1 PodK2A mice) phenocopied Ybx1 ΔPod mice, demonstrating a tubular-protective effect of YBX1 secreted from podocytes. Lipopolysaccharide-induced tubular injury was aggravated in Ybx1 ΔPod and Ybx1 PodK2A mice, indicating a pathophysiological relevance of this glomerular-tubular crosstalk. Thus, our data show that YBX1 is physiologically secreted from podocytes, thereby negatively modulating sterile inflammation in the tubular compartment, apparently by binding to and inhibiting tubular TLR4 signaling. Hence, we have uncovered an YBX1-dependent molecular mechanism of glomerular-tubular crosstalk., (Copyright © 2023 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)