Synovial tissue infiltration by pro-inflammatory macrophages is a critical factor in the pathogenesis of rheumatoid arthritis (RA), correlating strongly with high disease activity scores in affected joints and often lead to progressive joint damage and disability. Methotrexate (MTX) is the frontline therapeutic drug for RA, but its efficacy is hampered by short plasma half-life, reduced bioavailability, and severe adverse effects. To address these limitations, we developed an injectable polymer-nanomedicine supramolecular hydrogel (PNSH) with dynamic mechanical properties and morphology tailored for intra-articular administration and sustained drug release with minimized off-target toxicity. The hydrogel was assembled from MTX-loaded polymeric nanoparticles chemically conjugated with partially oxidized glucomannan. In vitro and in vivo studies demonstrate that PNSH exhibits low cytotoxicity and superior biocompatibility. It supports the sustained release of MTX, which promotes M1 macrophage remodeling towards the M2 macrophage via switching IRF5 and IRF8 to IRF3 and IRF4 through the adenosine A2A receptor (A2AR) signaling pathway. In a rat arthritis model, PNSH effectively mitigated tissue-damaging inflammation and restored the articular immune homeostasis, thereby inhibiting arthritis progression. Notably, PNSH also upregulated CD73 and A2AR, key components of the extracellular purinergic signaling pathway, promoted the transcriptional expression of IRF3 and IRF4, and significantly decreased the transcriptional expression of IRF5 and IRF8, driving macrophage re-polarization towards M2 phenotype. These findings suggest that PNSH has the potential to serve as a novel drug delivery system for regulating inflammation and treating RA.
© 2025 The Authors.

This study aimed to evaluate the role of alpha- and delta-cell signals on beta-cells within pancreatic mouse islets. Specifically, we investigated how these signals regulate glucose sensitivity, gene expression and function in beta-cells.
We first implemented our previous protocol to FACS purify alpha-, beta-, and delta-cells by adding CD81 as a positive marker for alpha-cells. We next developed an approach to reaggregate these sorted cell populations, creating chimeric islets with different proportions of each endocrine cell type. We used these chimeric islets to study the effect of alpha- and delta-cells on glucose sensitivity, gene expression and function in beta-cells.
We generated chimeric islets containing either all three endocrine cell types, alpha- + beta-cells or only beta-cells. We demonstrate that beta-cell glucose sensitivity and identity are independent of signals from alpha- and delta-cells. We identified a subset of genes including Pro-dynorphin, Fumarate hydratase and Txnip whose expression in beta-cells depends on alpha-cells signals acting through the glucagon- and glucagon-like peptide receptors. Finally, we demonstrated that in mouse beta-cell, KCl-mediated insulin secretion relies on an activation of the glucagon-receptor, while glucose-stimulated insulin secretion depends on glucagon-like peptide receptor activation.
We developed an innovative and easy-to-use model to reconstruct chimeric islets containing different frequencies of alpha-, beta- and delta-cells. Through this approach, we provide new insights into the complex regulatory mechanisms governing the role of alpha and delta cells on beta-cell features within islets.
Copyright © 2025 The Author(s). Published by Elsevier GmbH.. All rights reserved.

The adhesion G protein-coupled receptor ADGRE5/CD97 is upregulated in many cancers, representing a potential drug target in oncology/immuno-oncology. Yet, ADGRE5's activation and signaling mechanisms remain poorly understood. Here, we used enhanced bystander bioluminescence resonance energy transfer (ebBRET)-based biosensors and three strategies to characterize human (h) ADGRE5 signaling. First, a synthetic tobacco etch virus (TEV) protease-cleavable receptor chimera enabling controlled tethered agonist (TA) exposure at the GPCR proteolysis site (GPS) revealed signaling through Gα12 and Gα13, along with the recruitment of β-Arrestins 1/2 (β-Arrs). Second, we investigated WT hADGRE5 signaling elicited by Gingipain K (Kgp), an endopeptidase that cleaves hADGRE5 upstream of the GAIN domain. Kgp mirrored TEV-induced signaling but also promoted Gαz and Gα11 activity. The abolition of hADGRE5's GPS did not block Kgp-induced receptor activation, revealing a GPS cleavage-independent mechanism of action. Finally, we developed an assay to study hADGRE5 mechanical stimulation (MS) using β-Arr2 as a readout. MS promoted β-Arr2 recruitment in hADGRE5-expressing cells, and this response was lost upon abolition of the GPS. A neutralizing antibody to the hADGRE5 ligand CD55 significantly dampened MS-induced β-Arr2 engagement. Overall, this study advances our understanding of hADGRE5's signaling and highlights the receptor's plasticity in activating pathways via both GPS cleavage-dependent and -independent mechanisms.

Adhesion G protein-coupled receptors (GPCRs) play crucial roles in numerous physiological and pathological conditions. However, the functions of adhesion GPCRs remain poorly understood because of the lack of effective modulators. Here, we used the adhesion GPCR D1 (ADGRD1/GPR133) as a model to unveil a strategy for finding exogenous agonists that target adhesion GPCRs while revealing previously unidentified functions of ADGRD1. We identified the small molecule GL64 as a selective agonist of ADGRD1. GL64 activates ADGRD1 by mimicking the stachel sequence. Using GL64 as a chemical tool, we demonstrated that ADGRD1 negatively regulates bone loss by inhibiting osteoclastogenesis. The cAMP-PKA-NFATC1 pathway was identified as the downstream signaling pathway of ADGRD1 in osteoclasts. Furthermore, administering GL64 prevented bone loss and suppressed osteoclast activity in the osteoporosis mouse model induced by ovariectomy. Our findings provide mechanistic insights into the activation of adhesion GPCRs by exogenous agonists and underscore the therapeutic potential of targeting ADGRD1 in osteoclast-related diseases.

β-adrenergic blockers (β-blockers) are extensively used to inhibit β-adrenoceptor activation and subsequent cAMP production in many cell types. In this study, we characterized the effects of β-blockers on mouse pancreatic β-cells. Unexpectedly, high concentrations (100 μM) of β-blockers (propranolol and bisoprolol) paradoxically increased cAMP levels 5-10 fold, enhanced Ca2+ influx, and stimulated a 2-4 fold increase in glucose- and glimepiride-induced insulin secretion in MIN6-K8 clonal β-cells and isolated mouse pancreatic islets. These effects were observed despite minimal expression of β-adrenoceptors in these cells. Mechanistically, the cAMP increase led to ryanodine receptor 2 (RYR2) phosphorylation via protein kinase A (PKA), triggering Ca2+-induced Ca2+ release (CICR). CICR then activates transient receptor potential cation channel subfamily M member 5 (TRPM5), resulting in increased Ca2+ influx via voltage-dependent Ca2+ channels. These effects contradict the conventional understanding of the pharmacology of β-blockers, highlighting the variability in β-blocker actions depending on the experimental context.
© 2025 The Author(s). Pharmacology Research & Perspectives published by British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics and John Wiley & Sons Ltd.