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Proteasome inhibitors (PIs) are the backbone of combination treatments for patients with multiple myeloma and AL amyloidosis, while also indicated in Waldenström's macroglobulinemia and other malignancies. PIs act on proteasome peptidases, causing proteome instability due to accumulating aggregated, unfolded, and/or damaged polypeptides; sustained proteome instability then induces cell cycle arrest and/or apoptosis. Carfilzomib, an intravenous irreversible PI, exhibits a more severe cardiovascular toxicity profile as compared with the orally administered ixazomib or intravenous reversible PI such as bortezomib. Cardiovascular toxicity includes heart failure, hypertension, arrhythmias, and acute coronary syndromes. Because PIs are critical components of the treatment of hematological malignancies and amyloidosis, managing their cardiovascular toxicity involves identifying patients at risk, diagnosing toxicity early at the preclinical level, and offering cardioprotection if needed. Future research is required to elucidate underlying mechanisms, improve risk stratification, define the optimal management strategy, and develop new PIs with safe cardiovascular profiles., Competing Interests: Dr Janssen has been a consultant for Pfizer, Genesis Pharma, Amgen, and Takeda; has received research funding from Pfizer and Amgen; and has received honoraria and other paid expenses from Pfizer, Genesis Pharma, Amgen, and Takeda. Dr Dimopoulos has been a consultant, served on advisory boards, and has received personal fees/honoraria from BMS, Celgene, Takeda, Janssen, and Amgen; has received research funding from Takeda, Janssen, and Amgen; and has served on speakers bureaus for Celgene, Takeda, Janssen, and Amgen. Dr Stamatelopoulos has been a consultant for and received research funding and honoraria from Amgen. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

The bone resorbing osteoclasts are a complex type of cell essential for in vivo bone remodeling. There is no consensus on medium composition and seeding density for in vitro osteoclastogenesis, despite the importance thereof on osteoclastic differentiation and activity. The aim of this study was to investigate the relative effect of monocyte or peripheral blood mononuclear cell (PBMC) seeding density, osteoclastic supplement concentration and priming on the in vitro generation of functional osteoclasts, and to explore and evaluate the usefulness of commonly used markers for osteoclast cultures. Morphology and osteoclast formation were analyzed with fluorescence imaging for tartrate resistant acid phosphatase (TRAP) and integrin β3 (Iβ3). TRAP release was analyzed from supernatant samples, and resorption was analyzed from culture on Corning® Osteo Assay plates. In this study, we have shown that common non-standardized culturing conditions of monocyte or PBMCs had a significant effect on the in vitro generation of functional osteoclasts. We showed how increased osteoclastic supplement concentrations supported osteoclastic differentiation and resorption but not TRAP release, while priming resulted in increased TRAP release as well. Increased monocyte seeding densities resulted in more and large TRAP positive bi-nuclear cells, but not directly in more multinucleated osteoclasts, resorption or TRAP release. Increasing PBMC seeding densities resulted in more and larger osteoclasts and more resorption, although resorption was disproportionally low compared to the monocyte seeding density experiment. Exploration of commonly used markers for osteoclast cultures demonstrated that Iβ3 staining was an excellent and specific osteoclast marker in addition to TRAP staining, while supernatant TRAP measurements could not accurately predict osteoclastic resorptive activity. With improved understanding of the effect of seeding density and osteoclastic supplement concentration on osteoclasts, experiments yielding higher numbers of functional osteoclasts can ultimately improve our knowledge of osteoclasts, osteoclastogenesis, bone remodeling and bone diseases., Competing Interests: All authors declare that they have no conflicts of interest., (© 2022 The Author(s).)

Background: Second- and third-generation BCR-ABL1 tyrosine kinase inhibitors (TKIs) are associated with cardiovascular adverse events (CVAEs) in patients with Philadelphia chromosome-positive (Ph+) leukemia., Objectives: We hypothesized that second- and third-generation BCR-ABL1 TKIs may cause CVAEs through the activation of Rho-associated coiled-coil containing kinase (ROCK)., Methods: Peripheral blood mononuclear cells from 53 Ph+ patients on TKIs and 15 control patients without Ph+ leukemia were assessed for ROCK activity through capillary electrophoresis (median follow-up = 26 months [Q1-Q3: 5-37 months]). We also investigated the effects of TKIs and ROCK on endothelial dysfunction in vitro, which could contribute to CVAEs., Results: Patients receiving second- and third-generation TKIs had 1.6-fold greater ROCK activity compared with patients receiving imatinib and control patients. Elevated ROCK activity was associated with an increased incidence of CVAEs in Ph+ leukemia patients. In endothelial cells in vitro, we found that dasatinib and ponatinib treatment led to changes in actin intensity and endothelial permeability, which can be reversed by pharmacologic inhibition of ROCK. Ponatinib led to decreased cell proliferation, but this was not accompanied by senescence. Dasatinib and ponatinib treatment led to phosphor-inhibition of endothelial nitric oxide synthase and decreased nitric oxide production. ROCK inhibition reversed endothelial permeability and endothelial nitric oxide synthase-related endothelial dysfunction. Imatinib and nilotinib induce phosphorylation of p190RhoGAP., Conclusions: Our findings suggest ROCK activity may be a prognostic indicator of CVAEs in patients receiving BCR-ABL1 TKIs. With further study, ROCK inhibition may be a promising approach to reduce the incidence of CVAEs associated with second- and third-generation BCR-ABL1 TKIs., Competing Interests: This work was supported by a Stanford Medical Scholars Fellowship and AHA Predoctoral Fellowship to Dr Yu; National Heart, Lung, and Blood Institute T32-HL007381 to Dr Sladojevic; grant support from Ariad to Dr Larson; and National Institutes of Health R01-HL136962 to Dr Liao. Dr Larson reports being a consultant or advisor to Amgen, Ariad/Takeda, Celgene/Bristol Myers Squibb, CVS/Caremark, Epizyme, MorphoSys, and Novartis; has received clinical research support to his institution from Astellas, Celgene, Cellectis, Daiichi Sankyo, Forty-Seven/Gilead, Novartis, and Rafael Pharmaceuticals; and has received royalties from UpToDate. Dr Liao reports being a consultant or advisor to Esperion. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2022 The Authors.)

The coronavirus disease (COVID-19) pandemic caused by SARS-CoV-2 is ongoing. Individuals with sarcoidosis tend to develop severe COVID-19; however, the underlying pathological mechanisms remain elusive. To determine common transcriptional signatures and pathways between sarcoidosis and COVID-19, we investigated the whole-genome transcriptome of peripheral blood mononuclear cells (PBMCs) from patients with COVID-19 and sarcoidosis and conducted bioinformatic analysis, including gene ontology and pathway enrichment, protein-protein interaction (PPI) network, and gene regulatory network (GRN) construction. We identified 33 abnormally expressed genes that were common between COVID-19 and sarcoidosis. Functional enrichment analysis showed that these differentially expressed genes were associated with cytokine production involved in the immune response and T cell cytokine production. We identified several hub genes from the PPI network encoded by the common genes. These hub genes have high diagnostic potential for COVID-19 and sarcoidosis and can be potential biomarkers. Moreover, GRN analysis identified important microRNAs and transcription factors that regulate the common genes. This study provides a novel characterization of the transcriptional signatures and biological processes commonly dysregulated in sarcoidosis and COVID-19 and identified several critical regulators and biomarkers. This study highlights a potential pathological association between COVID-19 and sarcoidosis, establishing a theoretical basis for future clinical trials., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 Published by Elsevier Inc.)

Osteoclasts are the only cells in an organism capable of resorbing bone. These cells differentiate from monocyte/macrophage lineage cells upon stimulation by receptor activator of NF-κB ligand (RANKL). On the other hand, osteoclastogenesis is reportedly suppressed by glucose via the downregulation of NF-κB activity through suppression of reactive oxygen species generation. To examine whether other sugars might also affect osteoclast development, we compared the effects of monomeric sugars (glucose, galactose, N -acetylglucosamine (GlcNAc), and N -acetylgalactosamine (GalNAc)) on the osteoclastogenesis of murine RAW264 cells. Our results demonstrated that, in addition to glucose, both GlcNAc and GalNAc, which each have little effect on the generation of reactive oxygen species, suppress osteoclastogenesis. We hypothesized that GlcNAc might affect osteoclastogenesis through the upregulation of O -GlcNAcylation and showed that GlcNAc increases global O -GlcNAcylation, thereby suppressing the RANKL-dependent phosphorylation of NF-κB p65. Furthermore, an inhibitor of N -acetyl-β- D -glucosaminidase, O -(2-acetamido-2-deoxy- D -glucopyranosylidene) amino N -phenylcarbamate (PUGNAc), which also increases O -GlcNAcylation, suppressed the osteoclastogenesis of RAW264 cells and that of human peripheral blood mononuclear cells. Together, these data suggest that GlcNAc suppresses osteoclast differentiation in part through the promotion of O-GlcNAcylation.