Stimulation of Vibratory Urticaria-Associated Adhesion-GPCR, EMR2/ADGRE2, Triggers the NLRP3 Inflammasome Activation Signal in Human Monocytes

Genome-wide association study of exercise-induced skeletal muscle hypertrophy and the construction of predictive model

The aim of the current study was to investigate interindividual differences in muscle thickness of the rectus femoris (MTRF) following 12 wk of resistance training (RT) or high-intensity interval training (HIIT) to explore the genetic architecture underlying skeletal muscle hypertrophy and to construct predictive models. We conducted musculoskeletal ultrasound assessments of the MTRF response in 440 physically inactive adults after the 12-wk exercise period. A genome-wide association study was used to identify variants associated with the MTRF response, separately for RT and HIIT. Using the polygenic predictor score (PPS), we estimated the genetic contribution to exercise-induced hypertrophy. Predictive models for the MTRF response were constructed using random forest (RF), support vector mac (SVM), and generalized linear model (GLM) in 10 cross-validated approaches. MTRF increased significantly after both RT (8.8%, P < 0.05) and HIIT (5.3%, P < 0.05), but with considerable interindividual differences (RT: -13.5 to 38.4%, HIIT: -14.2 to 30.7%). Eleven lead single-nucleotide polymorphisms in RT and eight lead single-nucleotide polymorphisms in HIIT were identified at a significance level of P < 1 × 10-5. The PPS was associated with the MTRF response, explaining 47.2% of the variation in response to RT and 38.3% of the variation in response to HIIT. Notably, the GLM and SVM predictive models exhibited superior performance compared with RF models (P < 0.05), and the GLM demonstrated optimal performance with an area under curve of 0.809 (95% confidence interval: 0.669-0.949). Factors such as PPS, baseline MTRF, and exercise protocol exerted influence on the MTRF response to exercise, with PPS being the primary contributor. The GLM and SVM predictive model, incorporating both genetic and phenotypic factors, emerged as promising tools for predicting exercise-induced skeletal muscle hypertrophy.NEW & NOTEWORTHY The interindividual variability induced muscle hypertrophy by resistance training (RT) or high-intensity interval training (HIIT) and the associated genetic architecture remain uncertain. We identified genetic variants that underlie RT- or HIIT-induced muscle hypertrophy and established them as pivotal factors influencing the response regardless of the training type. The genetic-phenotype predictive model developed has the potential to identify nonresponders or individuals with low responsiveness before engaging in exercise training.

Adhesion GPCR ADGRE2 Maintains Proteostasis to Promote Progression in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive and heterogeneous hematologic malignancy. In elderly patients, AML incidence is high and has a poor prognosis due to a lack of effective therapies. G protein-coupled receptors (GPCR) play integral roles in physiologic processes and human diseases. Particularly, one third of adhesion GPCRs, the second largest group of GPCRs, are highly expressed in hematopoietic stem and progenitor cells or lineage cells. Here, we investigate the role of adhesion GPCRs in AML and whether they could be harnessed as antileukemia targets. Systematic screening of the impact of adhesion GPCRs on AML functionality by bioinformatic and functional analyses revealed high expression of ADGRE2 in AML, particularly in leukemic stem cells, which is associated with poor patient outcomes. Silencing ADGRE2 not only exerts antileukemic effects in AML cell lines and cells derived from patients with AML in vitro, but also delays AML progression in xenograft models in vivo. Mechanistically, ADGRE2 activates phospholipase Cβ/protein kinase C/MEK/ERK signaling to enhance the expression of AP1 and transcriptionally drive the expression of DUSP1, a protein phosphatase. DUSP1 dephosphorylates Ser16 in the J-domain of the co-chaperone DNAJB1, which facilitates the DNAJB1-HSP70 interaction and maintenance of proteostasis in AML. Finally, combined inhibition of MEK, AP1, and DUSP1 exhibits robust therapeutic efficacy in AML xenograft mouse models. Collectively, this study deciphers the roles and mechanisms of ADGRE2 in AML and provides a promising therapeutic strategy for treating AML. Significance: Increased expression of the adhesion GPCR member ADGRE2 in AML supports leukemia stem cell self-renewal and leukemogenesis by modulating proteostasis via an MEK/AP1/DUSP1 axis, which can be targeted to suppress AML progression.

The Posttraumatic Increase of the Adhesion GPCR EMR2/ADGRE2 on Circulating Neutrophils Is Not Related to Injury Severity

Trauma triggers a rapid innate immune response to aid the clearance of damaged/necrotic cells and their released damage-associated molecular pattern (DAMP). Here, we monitored the expression of EMR2/ADGRE2, involved in the functional regulation of innate immune cells, on circulating neutrophils in very severely and moderately/severely injured patients up to 240 h after trauma. Notably, neutrophilic EMR2 showed a uniform, injury severity- and type of injury-independent posttraumatic course in all patients. The percentage of EMR2+ neutrophils and their EMR2 level increased and peaked 48 h after trauma. Afterwards, they declined and normalized in some, but not all, patients. Circulating EMR2+ compared to EMR2- neutrophils express less CD62L and more CD11c, a sign of activation. Neutrophilic EMR2 regulation was verified in vitro. Remarkably, it increased, depending on extracellular calcium, in controls as well. Cytokines, enhanced in patients immediately after trauma, and sera of patients did not further affect this neutrophilic EMR2 increase, whereas apoptosis induction disrupted it. Likely the damaged/necrotic cells/DAMPs, unavoidable during neutrophil culture, stimulate the neutrophilic EMR2 increase. In summary, the rapidly increased absolute number of neutrophils, especially present in very severely injured patients, together with upregulated neutrophilic EMR2, may expand our in vivo capacity to react to and finally clear damaged/necrotic cells/DAMPs after trauma.

Cooperative CAR targeting to selectively eliminate AML and minimize escape

Acute myeloid leukemia (AML) poses a singular challenge for chimeric antigen receptor (CAR) therapy owing to its phenotypic heterogeneity and similarity to normal hematopoietic stem/progenitor cells (HSPCs). Here we expound a CAR strategy intended to efficiently target AML while minimizing HSPC toxicity. Quantification of target expression in relapsed/refractory patient samples and normal HSPCs reveals a therapeutic window for gated co-targeting of ADGRE2 and CLEC12A: We combine an attenuated ADGRE2-CAR with a CLEC12A-chimeric costimulatory receptor (ADCLEC.syn1) to preferentially engage ADGRE2posCLEC12Apos leukemic stem cells over ADGRE2lowCLEC12Aneg normal HSPCs. ADCLEC.syn1 prevents antigen escape in AML xenograft models, outperforms the ADGRE2-CAR alone and eradicates AML despite proximate myelopoiesis in humanized mice. Off-target HSPC toxicity is similar to that of a CD19-CAR and can be mitigated by reducing CAR T cell-derived interferon-γ. Overall, we demonstrate the ability of target density-adapted cooperative CAR targeting to selectively eliminate AML and potentially obviate the need for hematopoietic rescue.

Adhesion G protein-coupled receptors: structure, signaling, physiology, and pathophysiology

Adhesion G protein-coupled receptors (AGPCRs) are a family of 33 receptors in humans exhibiting a conserved general structure but diverse expression patterns and physiological functions. The large NH2 termini characteristic of AGPCRs confer unique properties to each receptor and possess a variety of distinct domains that can bind to a diverse array of extracellular proteins and components of the extracellular matrix. The traditional view of AGPCRs, as implied by their name, is that their core function is the mediation of adhesion. In recent years, though, many surprising advances have been made regarding AGPCR signaling mechanisms, activation by mechanosensory forces, and stimulation by small-molecule ligands such as steroid hormones and bioactive lipids. Thus, a new view of AGPCRs has begun to emerge in which these receptors are seen as massive signaling platforms that are crucial for the integration of adhesive, mechanosensory, and chemical stimuli. This review article describes the recent advances that have led to this new understanding of AGPCR function and also discusses new insights into the physiological actions of these receptors as well as their roles in human disease.

Ligands and Beyond: Mechanosensitive Adhesion GPCRs

Cells respond to diverse types of mechanical stimuli using a wide range of plasma membrane-associated mechanosensitive receptors to convert extracellular mechanical cues into intracellular signaling. G protein-coupled receptors (GPCRs) represent the largest cell surface protein superfamily that function as versatile sensors for a broad spectrum of bio/chemical messages. In recent years, accumulating evidence has shown that GPCRs can also engage in mechano-transduction. According to the GRAFS classification system of GPCRs, adhesion GPCRs (aGPCRs) constitute the second largest GPCR subfamily with a unique modular protein architecture and post-translational modification that are well adapted for mechanosensory functions. Here, we present a critical review of current evidence on mechanosensitive aGPCRs.