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Background and Aims: Deficiency in the thiol transferase glutaredoxin 1 (Grx1) in aging mice promotes, in a sexually dimorphic manner, dysregulation of macrophages and atherogenesis. However, the underlying mechanisms are not known. Here we tested the hypothesis that macrophage-restricted overexpression of Grx1 protects atherosclerosis-prone mice against macrophage reprogramming and dysfunction induced by a high-calorie diet (HCD) and thereby reduces the severity of atherosclerosis., Methods: We generated lentiviral vectors carrying cluster of differentiation 68 (CD68) promoter-driven enhanced green fluorescent protein (EGFP) or Grx1 constructs and conducted bone marrow (BM) transplantation studies to overexpress Grx1 in a macrophage-specific manner in male and female atherosclerosis-prone LDLR -/- mice, and fed these mice a HCD to induce atherogenesis. Atherosclerotic lesion size was determined in both the aortic root and the aorta. We isolated BM-derived macrophages (BMDM) to assess protein S-glutathionylation levels and loss of mitogen-activated protein kinase phosphatase 1 (MKP-1) activity as measures of HCD-induced thiol oxidative stress. We also conducted gene profiling on these BMDM to determine the impact of Grx1 activity on HCD-induced macrophage reprogramming., Results: Overexpression of Grx1 protected macrophages against HCD-induced protein S-glutathionylation, reduced monocyte chemotaxis in vivo, limited macrophage recruitment into atherosclerotic lesions, and was sufficient to reduce the severity of atherogenesis in both male and female mice. Gene profiling revealed major sex differences in the transcriptional reprogramming of macrophages induced by HCD feeding, but Grx1 overexpression only partially reversed HCD-induced transcriptional reprogramming of macrophages., Conclusions: Macrophage Grx1 plays a major role in protecting mice atherosclerosis mainly by maintaining the thiol redox state of the macrophage proteome and preventing macrophage dysfunction., Competing Interests: Declaration of competing interest 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., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Cancer-induced bone pain (CIBP) is the most common and devastating symptom of bone metastatic cancer that substantially disrupts patients' quality of life. Currently, there are few effective analgesic treatments for CIBP other than opioids which come with severe side effects. In order to better understand the factors and mechanisms responsible for CIBP it is essential to have clinically relevant animal models that mirror pain-related symptoms and disease progression observed in patients with bone metastatic cancer. In the current study, we characterize a syngeneic mouse model of prostate cancer induced bone pain. We transfected a prostate cancer cell line (RM1) with green fluorescent protein (GFP) and luciferase reporters in order to visualize tumor growth longitudinally in vivo and to assess the relationship between sensory neurons and tumor cells within the bone microenvironment. Following intra-femoral injection of the RM1 prostate cancer cell line into male C57BL/6 mice, we observed a progressive increase in spontaneous guarding of the inoculated limb between 12 and 21 days post inoculation in tumor bearing compared to sham operated mice. Daily running wheel performance was evaluated as a measure of functional impairment and potentially movement evoked pain. We observed a progressive reduction in the distance traveled and percentage of time at optimal velocity between 12 and 21 days post inoculation in tumor bearing compared to sham operated mice. We utilized histological, radiographic and μCT analysis to examine tumor induced bone remodeling and observed osteolytic lesions as well as extra-periosteal aberrant bone formation in the tumor bearing femur, similar to clinical findings in patients with bone metastatic prostate cancer. Within the tumor bearing femur, we observed reorganization of blood vessels, macrophage and nerve fibers within the intramedullary space and periosteum adjacent to tumor cells. Tumor bearing mice displayed significant increases in the injury marker ATF3 and upregulation of the neuropeptides SP and CGRP in the ipsilateral DRG as well as increased measures of central sensitization and glial activation in the ipsilateral spinal cord. This immunocompetent mouse model will be useful when combined with cell type selective transgenic mice to examine tumor, immune cell and sensory neuron interactions in the bone microenvironment and their role in pain and disease progression associated with bone metastatic prostate cancer., 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., (© 2023 The Authors.)

Prostate cancer (PCa) metastasizes to bone, where the bone marrow microenvironment controls disease progression. However, the cellular interactions that result in active bone marrow metastases are poorly understood. A better understanding of these interactions is critical to success in the pursuit of effective treatments for this life ending disease. Anecdotally, we observe that after intracardiac injection of PCa cells, one of the greatest tools to investigate the mechanisms of bone-metastatic disease, animals frequently present with mandible metastasis before hind limb metastasis. Therefore, in this study, we investigated whether the bone cells derived from the mouse mandible influence PCa progression differently than those from the hind limb. Interestingly, we found that osteoblasts harvested from mouse mandibles grew faster, expressed more vascular endothelial growth factor (VEGF), increased vascularity and formed more bone, and stimulated faster growth of PCa cells when cultured together than osteoblasts harvested from mouse hind limbs. Additionally, these findings were confirmed in vivo when mouse mandible osteoblasts were co-implanted into mice with PCa cells. Importantly, the enhancement of PCa growth mediated by mandible osteoblasts was not shown to be due to their differentiation or proliferation activities, but may be partly due to increased vascularization and expression of VEGF., Competing Interests: Yusuke Shiozawa has received research funding from TEVA Pharmaceuticals, but not relevant to this study. The remaining 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., (© 2020 The Author(s).)

Proteoglycan 4 (PRG4), a critical protective factor in articular joints, is implicated in hematopoietic progenitor cell expansion and megakaryopoiesis. PRG4 loss-of-function mutations result in camptodactyly-arthropathy-coxa vara-pericarditis (CACP) syndrome, which is characterized primarily by precocious joint failure. PRG4 was identified as a novel parathyroid hormone (PTH) responsiveness gene in osteoblastic cells in bone, and was investigated as a potential mediator of PTH actions on hematopoiesis. Sixteen-week-old Prg4(-/-) mutant and Prg4(+/+) wild-type mice were treated daily with intermittent PTH (residues 1-34) or vehicle for 6 weeks. At 22 weeks of age, Prg4 mutant mice had increased peripheral blood neutrophils and decreased marrow B220(+) (B-lymphocytic) cells, which were normalized by PTH. The PTH-induced increase in marrow Lin(-)Sca-1(+)c-Kit(+) (hematopoietic progenitor) cells was blunted in mutant mice. Basal and PTH-stimulated stromal cell-derived factor-1 (SDF-1) was decreased in mutant mice, suggesting SDF-1 as a candidate regulator of proteoglycan 4 actions on hematopoiesis in vivo. PTH stimulation of IL-6 mRNA was greater in mutant than in wild-type calvaria and bone marrow, suggesting a compensatory mechanism in the PTH-induced increase in marrow hematopoietic progenitor cells. In summary, proteoglycan 4 is a novel PTH-responsive factor regulating immune cells and PTH actions on marrow hematopoietic progenitor cells., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)