Recombinant granulocyte colony-stimulating factor (G-CSF) is the most commonly used agent for treating neutropenia and mobilizing hematopoietic stem cells (HSCs) for transplantation. However, some patients do not respond effectively to the currently used mobilization protocols. To address this, new therapeutic approaches are needed. A potential strategy is pharmacological induction of endogenous mobilizing factors via cobalt protoporphyrin IX (CoPP). CoPP mobilizes HSCs and granulocytes by increasing endogenous G-CSF, though optimal dosing and potential side effects remain unclear. Our study aimed to optimize CoPP dosing and timing, and assess its safety in mobilizing cells from bone marrow to blood.
Mice were treated with different doses of CoPP, and blood cell counts, cytokine concentrations, and organ damage markers were evaluated at various time points after injection.
Our results show that CoPP exerts a dose-dependent mobilizing effect, with the highest G-CSF levels and number of mobilized leukocytes observed in mice treated with 10 mg/kg of CoPP. While there were no severe adverse effects, there were mild fluctuations in markers of organ function, including a reduction in blood urea nitrogen (BUN) and glucose levels during the five days of administration. Additionally, although most parameters normalized within 30 days, the decrease in BUN persisted. Mice experienced short-term weight loss following CoPP administration, but they regained their initial weight within two weeks.
This study demonstrates that CoPP mobilizes cells from the bone marrow to the blood in a dose-dependent manner, with mild side effects, including temporary changes in biochemical markers and a sustained reduction in BUN levels.
© 2025. The Author(s).

A generic level of chromatin organization generated by the interplay between cohesin and CTCF suffices to limit promiscuous interactions between regulatory elements, but a lineage-specific chromatin assembly that supersedes these constraints is required to configure the genome to guide gene expression changes that drive faithful lineage progression. Loss-of-function approaches in B cell precursors show that IKAROS assembles interactions across megabase distances in preparation for lymphoid development. Interactions emanating from IKAROS-bound enhancers override CTCF-imposed boundaries to assemble lineage-specific regulatory units built on a backbone of smaller invariant topological domains. Gain of function in epithelial cells confirms IKAROS' ability to reconfigure chromatin architecture at multiple scales. Although the compaction of the Igκ locus required for genome editing represents a function of IKAROS unique to lymphocytes, the more general function to preconfigure the genome to support lineage-specific gene expression and suppress activation of extra-lineage genes provides a paradigm for lineage restriction.
Published by Elsevier Inc.

Cub domain-containing protein 1 (CDCP1) is a protein that is highly expressed on the surface of many cancer cells. However, its distribution in normal tissues and its potential roles in nontumor cells are poorly understood. We found that CDCP1 is present on both human and mouse retinal pigment epithelial (RPE) cells. CDCP1-KO mice developed attenuated retinal inflammation in a passive model of autoimmune uveitis, with disrupted tight junctions and infiltrating T cells detected in RPE flat mounts from WT but not CDCP1-KO mice during EAU development. Mechanistically, we discovered that CDCP1 on RPE cells was upregulated by IFN-γ in vitro and after EAU induction in vivo. CD6 stimulation induced increased RPE barrier permeability of WT but not CDCP1-knockdown (CDCP1-KD) RPE cells, and activated T cells migrated through WT RPE monolayers more efficiently than the CDCP1-KD RPE monolayers. In addition, CD6 stimulation of WT but not the CDCP1-KD RPE cells induced massive stress fiber formation and focal adhesion disruption to reduce cell barrier tight junctions. These data suggest that CDCP1 on RPE cells interacts with CD6 on T cells to induce RPE cytoskeleton remodeling and focal adhesion disruption, which open up the tight junctions to facilitate T cell infiltration for the development of uveitis.

Effector CD8 + T cell interactions are critical in controlling viral infection by directly killing infected cells but overabundant or sustained activation also exacerbates tissue damage. Chemokines promote the trafficking of effector CD8 + T cells into infected tissues, but we know little about how chemokines regulate the function of CD8 + T cells within tissues. Using a murine model of influenza A virus infection, we found that expression of the chemokine receptor CXCR4 by lung-infiltrating cytotoxic T cells correlated with the expression of the degranulation marker CD107a. Inhibition of CXCR4 reduced activation, adhesion, and degranulation of cytotoxic T cells in vitro and in vivo . Moreover, in live influenza-infected lung tissue, T cells stopped moving in lung regions with high levels of influenza antigen, and CXCR4 was essential for CD8 + T cells to execute this arrest signal fully. In contrast, CXCR4 increased the motility of CD8 + T cells in low-influenza areas of the lung. We also found that CXCR4 stimulated the effector function of lung-infiltrating cytotoxic T cells even after clearance of influenza virus, and inhibition of CXCR4 expedited the recovery of influenza-infected mice, despite delayed clearance of the replication-competent virus. Our results suggest that CXCR4 promotes the interaction strength of cytotoxic T cells in lung tissue through combined effects on T cell movement and interaction with virally infected target cells in influenza infected-lungs.

Although microbe-associated molecular pattern (MAMP) molecules can promote cholesterol accumulation in macrophages, the existence of a host-derived MAMP inactivation mechanism that prevents foam cell formation has not been described. Here, we tested the ability of acyloxyacyl hydrolase (AOAH), the host lipase that inactivates gram-negative bacterial lipopolysaccharides (LPSs), to prevent foam cell formation in mice. Following exposure to small intraperitoneal dose(s) of LPSs, Aoah -/- macrophages produced more low-density lipoprotein receptor and less apolipoprotein E and accumulated more cholesterol than did Aoah +/+ macrophages. The Aoah -/- macrophages also maintained several pro-inflammatory features. Using a perivascular collar placement model, we found that Aoah -/- mice developed more carotid artery foam cells than did Aoah +/+ mice after they had been fed a high fat, high cholesterol diet, and received small doses of LPSs. This is the first demonstration that an enzyme that inactivates a stimulatory MAMP in vivo can reduce cholesterol accumulation and inflammation in arterial macrophages.
© 2021 The Authors.