revealing-electromechanical-control-tissue-homeostasis-using-two

Revealing Electromechanical Control of Tissue Homeostasis Using a Two-Layer Microfluidic Device

Cell behavior and cell fate are impacted by electric currents or fields that are endogenous or externally applied. Static electric signals can be applied ...

Westlake University

Intravascular transplantation of human-induced pluripotent stem cells (hiPSCs) demonstrated a significant therapeutic effect in the treatment of restenosis by the paracrine function of extracellular vesicles (EVs). However, the risk of tumorigenicity and poor cell survival limits its clinical applications. In this study, we for the first time applied a highly efficient and robust three-dimensional (3D) protocol for hiPSC differentiation into endothelial cells (ECs) with subsequent isolation of EVs from the derived hiPSC-EC (ECs differentiated from hiPSCs), and validated their therapeutic effect in intimal hyperplasia (IH) models. We found that intravenously (iv) injected EVs could accumulate on the carotid artery endothelium and significantly alleviate the intimal thickening induced by the carotid artery ligation. To elucidate the mechanism of this endothelial protection, we performed miRNA expression profiling and found out that among the most conserved endothelial miRNAs, miR-126 was the most abundant in hiPSC-EC-produced EVs (hiPSC-EC-EV). MiR-126 depletion from hiPSC-EC-EV can hinder its protective effect on human umbilical vein endothelial cells (HUVECs) in an inflammatory process. A variety of functional  studies revealed that miR-126 was able to prevent endothelial apoptosis after inflammatory stimulation, as well as promote EC migration and tube formation through autophagy upregulation. The latter was supported by  studies demonstrating that treatment with hiPSC-EC-EV can upregulate autophagy in mouse carotid artery ECs, thereby preventing IH and modulating vascular homeostasis via remodeling of the vascular intima. Our findings suggest a regulatory mechanism for the therapeutic effect on arterial restenosis by autophagy regulation, and provide a potential strategy for clinical treatment of the disease.

Extracellular vesicles produced by human-induced pluripotent stem cell-derived endothelial cells can prevent arterial stenosis in mice via autophagy regulation.

No drug options exist for skeletal muscle atrophy in clinical, which poses a huge socio-economic burden, making development on drug interventions a general wellbeing need. Patients with a variety of pathologic conditions associated with skeletal muscle atrophy have systemically elevated inflammatory factors. Morroniside, derived from medicinal herb , possesses anti-inflammatory effect. However, whether and how morroniside combat muscle atrophy remain unknown. Here, we identified crucial genetic associations between TNFα/NF-κB pathway and grip strength based on population using 377,807 European participants from the United Kingdom Biobank dataset. Denervation increased TNFα in atrophying skeletal muscles, which inhibited myotube formation . Notably, morroniside treatment rescued TNFα-induced myotube atrophy  and impeded skeletal muscle atrophy , resulting in increased body/muscles weights, No. of satellite cells, size of type IIA, IIX and IIB myofibers, and percentage of type IIA myofibers in denervated mice. Mechanistically,  and/or  studies demonstrated that morroniside could not only inhibit canonical and non-canonical NF-κB, inflammatory mediators (IL6, IL-1b, CRP, NIRP3, PTGS2, TNFα), but also down-regulate protein degradation signals (Follistatin, Myostatin, ALK4/5/7, Smad7/3), ubiquitin-proteasome molecules (FoxO3, Atrogin-1, MuRF1), autophagy-lysosomal molecules (Bnip3, LC3A, and LC3B), while promoting protein synthesis signals (IGF-1/IGF-1R/IRS-1/PI3K/Akt, and BMP14/BMPR2/ALK2/3/Smad5/9). Moreover, morroniside had no obvious liver and kidney toxicity. This human genetic, cells and mice pathological evidence indicates that morroniside is an efficacious and safe inflammatory muscle atrophy treatment and suggests its translational potential on muscle wasting.

Morroniside ameliorates inflammatory skeletal muscle atrophy  inhibiting canonical and non-canonical NF-κB and regulating protein synthesis/degradation.

With the development of coronary angiography, more and more attention has been paid to coronary slow flow phenomenon (CSFP). Recent studies have found that the correlation between homocysteine (Hcy) levels and CSFP was contradictory, so we conducted this meta-analysis to investigate the correlation.

Homocysteine levels in patients with coronary slow flow phenomenon: A meta-analysis.

The identification of readers, an important class of proteins that recognize modified residues at specific sites, is essential to uncover the biological roles of post-translational modifications. Photoreactive crosslinkers are powerful tools for investigating readers. However, existing methods usually employ synthetically challenging photoreactive warheads, and their high-energy intermediates generated upon irradiation, such as nitrene and carbene, may cause substantial non-specific crosslinking. Here we report dimethylsulfonium as a methyllysine mimic that binds to specific readers and subsequently crosslinks to a conserved tryptophan inside the binding pocket through single-electron transfer under ultraviolet irradiation. The crosslinking relies on a protein-templated σ-π electron donor-acceptor interaction between sulfonium and indole, ensuring excellent site selectivity for tryptophan in the active site and orthogonality to other methyllysine readers. This method could escalate the discovery of methyllysine readers from complex cell samples. Furthermore, this photo crosslinking strategy could be extended to develop other types of microenvironment-dependent conjugations to site-specific tryptophan.

Single-electron transfer between sulfonium and tryptophan enables site-selective photo crosslinking of methyllysine reader proteins.

Arginine methylation is an important posttranslational modification that regulates epigenetics and pre-mRNA splicing. Similar to lysine methylation, reader proteins that bind site-specific modified proteins are key mediators for arginine methylation functions. Some arginine methylation has been shown significant functions from phenotype, but the molecular mechanisms remain elusive, probably due to lack of identification of the readers. Current methods rely on methylarginine peptide tools for pull-down or binding assays, but affinities to readers are usually tens to hundreds micromolar. As a consequence, development of chemical probes that crosslink specific readers is much in demand. We recently reported a methyllysine reader-selective crosslinking strategy by sulfonium peptides. NleSme2 (norleucine-ε-dimethylsulfonium) imitate dimethyllysine and crosslink tryptophan or tyrosine inside binding pocket of readers. Arginine methylation readers contain aromatic cages for methylarginine binding, that is the similar binding mechanism for methyllysine. Therefore, we developed sulfonium probes that mimic methylarginine and crosslink tryptophan or tyrosine inside reader binding pockets. Because the single electron transfer from aromatic residue to sulfonium is binding-dependent, the conjugation showed high selectivity. Therefore, such sulfonium probes could be applied broadly for methylarginine readers investigations.

Selective photo crosslinking to methylarginine readers by sulfonium peptides.

Sulfonium is an electrophilic and biocompatible group that is widely applied in synthetic chemistry on small molecules. However, there have been few developments of peptide or protein-based sulfonium tools. We recently reported sulfonium-mediated tryptophan crosslinking and developed NleSme2 (norleucine-dimethylsulfonium) peptides as dimethyllysine mimics that crosslink site-specific methyllysine readers. Therefore, sulfonium probes show great potential for investigating methyllysine readers and other aromatic cage-containing proteins. However, the current synthesis is not very efficient and is limited to peptide probes that, in many cases, cannot mimic protein-protein interactions. In addition to peptidyl conjugates that are valuable for reader identification, there are unavoidable methyl conjugates as side products. As a result, a robust method to prepare peptide and protein sulfonium tools with great crosslinking reactivity and selectivity is highly desirable. Here, we report a cysteine alkylation method to introduce site-specific sulfonium at protein level with excellent yield. In addition to dimethylsulfonium, we also developed cyclic sulfonium warheads that enhanced peptidyl conjugate selectivity. The method thus made it possible to prepare nucleosome probes in which LEDGF and NSD2, as H3K36 methylation readers were readily crosslinked. We thus believe this method will accelerate the development of sulfonium peptide and protein tool sets for broad applications in chemical biology studies.

Article	Year
Extracellular vesicles produced by human-induced pluripotent stem cell-derived endothelial cells can prevent arterial stenosis in mice via autophagy regulation. Frontiers in cardiovascular medicine\| PubMed ID: 36324745	2022
Morroniside ameliorates inflammatory skeletal muscle atrophy inhibiting canonical and non-canonical NF-κB and regulating protein synthesis/degradation. Frontiers in pharmacology\| PubMed ID: 36618945	2022
Homocysteine levels in patients with coronary slow flow phenomenon: A meta-analysis. PloS one\| PubMed ID: 37418362	2023
Single-electron transfer between sulfonium and tryptophan enables site-selective photo crosslinking of methyllysine reader proteins. Nature chemistry\| PubMed ID: 39079947	2024
Selective photo crosslinking to methylarginine readers by sulfonium peptides. Bioorganic & medicinal chemistry\| PubMed ID: 39642578	2025
Facile preparation of sulfonium peptide and protein probes for selective crosslinking of methyllysine readers. Chemical science\| PubMed ID: 39720136	2025

Feng Feng

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