Engineering D-Amino Acid Containing Collagen Like Peptide at the Cleavage Site of Clostridium histolyticum Collagenase for Its Inhibition

Expanding the chemical repertoire of protein-based polymers for drug-delivery applications

Expanding the chemical repertoire of natural and artificial protein-based polymers (PBPs) can enable the production of sequence-defined, yet chemically diverse, biopolymers with customized or new properties that cannot be accessed in PBPs composed of only natural amino acids. Various approaches can enable the expansion of the chemical repertoire of PBPs, including chemical and enzymatic treatments or the incorporation of unnatural amino acids. These techniques are employed to install a wide variety of chemical groups-such as bio-orthogonally reactive, cross-linkable, post-translation modifications, and environmentally responsive groups-which, in turn, can facilitate the design of customized PBP-based drug-delivery systems with modified, fine-tuned, or entirely new properties and functions. Here, we detail the existing and emerging technologies for expanding the chemical repertoire of PBPs and review several chemical groups that either demonstrate or are anticipated to show potential in the design of PBP-based drug delivery systems. Finally, we provide our perspective on the remaining challenges and future directions in this field.

A Novel Proteomics-Based Strategy for the Investigation of Peptide Sequences in Extraterrestrial Samples

Method development is one of the objectives of the astrophysical community for characterizing the organic matter in objects of the solar system. In this context, we report on the development of an enzyme-catalyzed stereoselective hydrolysis, inspired by the proteomics discipline, which has enabled the indirect detection of peptide sequences in extraterrestrial samples. A proof of concept has been performed on a Murchison extract. We show that our approach can successfully highlight l- and d-amino acids involved in peptide bonds. While we show that some d-amino acids must have been involved in peptide bonds, we cannot at this stage conclude on the indigenous or exogenous nature of these biopolymers. However, our strategy constitutes the first step toward direct UPLC-MS evidence of peptide sequences in extraterrestrial samples. It should thus contribute to deepening knowledge on the molecules available in the solar system, hence providing new clues about their chemical history, especially on Earth.

Anti-Double-Stranded DNA IgG Participates in Renal Fibrosis through Suppressing the Suppressor of Cytokine Signaling 1 Signals

Suppressor of cytokine signaling 1 (SOCS1) participates in renal fibrosis by downregulating Janus kinase 2 (JAK2)/signal transducer and activator of transcription 1 (STAT1)-mediated cytokine signaling. Recently, it was found that anti-double-stranded DNA (dsDNA) IgG induces the synthesis of profibrotic cytokines by renal cells. To explore the potential effect of anti-dsDNA IgG on SOCS1-mediated renal fibrosis, kidney tissues were collected from patients with lupus nephritis (LN) as well as MRL/lpr lupus-prone mice. The SOCS1 expression was evaluated in tissue samples. In addition, SCID mice were injected with anti-dsDNA IgG, followed by evaluation of SOCS1 levels. Renal resident cells were cultured in vitro, receiving the stimulation of anti-dsDNA IgG and then the measurement of SOCS1, JAK2, STAT1α, and profibrotic cytokines. Moreover, the binding of anti-dsDNA IgG to SOCS1 kinase inhibitory region (KIR) peptide was analyzed by surface plasmon resonance. We found that SOCS1 expression was inhibited, but JAK2/STAT1 activation was prominent in the kidney tissues of patients with LN, MRL/lpr mice, or anti-dsDNA IgG-injected SCID mice. The cultured renal cells also showed SOCS1 downregulation, JAK2/STAT1 activation, and profibrotic cytokine promotion upon anti-dsDNA IgG stimulation. Surprisingly, anti-dsDNA IgG showed high affinity to KIR peptide and competed with JAK2 loop for KIR. Additionally, a DNA-mimicking peptide (ALW) blocked the binding of anti-dsDNA IgG to KIR, and even partially abrogated the activation of JAK2/STAT1α signals and the expression of profibrotic cytokines in SCID mice. In conclusion, anti-dsDNA IgG downregulates SOCS1 expression, activates JAK2/STAT1 signals, and contributes to renal fibrosis; its peptide blockade may restore the SOCS1 inhibitory effect on the production of profibrotic cytokine, and finally ameliorate renal fibrosis in LN.

Hydrogels based on collagen and fibrin – frontiers and applications

Hydrogels are a versatile tool for a multitude of applications in biomedical research and clinical practice. Especially collagen and fibrin hydrogels are distinguished by their excellent biocompatibility, natural capacity for cell adhesion and low immunogenicity. In many ways, collagen and fibrin represent an ideal biomaterial, as they can serve as a scaffold for tissue regeneration and promote the migration of cells, as well as the ingrowth of tissues. On the other hand, pure collagen and fibrin materials are marked by poor mechanical properties and rapid degradation, which limits their use in practice. This paper will review methods of modification of natural collagen and fibrin materials to next-generation materials with enhanced stability. A special focus is placed on biomedical products from fibrin and collagen already on the market. In addition, recent research on the in vivo applications of collagen and fibrin-based materials will be showcased.

Does L to D-amino acid substitution trigger helix→sheet conformations in collagen like peptides adsorbed to surfaces?

The present work reports on the structural order, self assembling behaviour and the role in adsorption to hydrophilic or hydrophobic solid surfaces of modified sequence from the triple helical peptide model of the collagenase cleavage site in type I collagen (Uniprot accession number P02452 residues from 935 to 970) using (D)Ala and (D)Ile substitutions as given in the models below: Model-1: GSOGADGPAGAOGTOGPQGIAGQRGVV GLOGQRGER. Model-2: GSOGADGP(D)AGAOGTOGPQGIAGQRGVVGLOGQRGER. Model-3: GSOGADGPAGAOGTOGPQG(D)IAGQRGVVGLOGQRGER. Collagenase is an important enzyme that plays an important role in degrading collagen in wound healing, cancer metastasis and even in embryonic development. However, the mechanism by which this degradation occurs is not completely understood. Our results show that adsorption of the peptides to the solid surfaces, specifically hydrophobic triggers a helix to beta transition with order increasing in peptide models 2 and 3. This restricts the collagenolytic behaviour of collagenase and may find application in design of peptides and peptidomimetics for enzyme-substrate interaction, specifically with reference to collagen and other extra cellular matrix proteins.