Oxalate Alters Cellular Bioenergetics, Redox Homeostasis, Antibacterial Response, and Immune Response in Macrophages

Abstract

Individuals with calcium oxalate (CaOx) kidney stones can have secondarily infected calculi which may play a role in the development of recurrent urinary tract infection (UTI). Uropathogenic Escherichia coli (UPEC) is the most common causative pathogen of UTIs. Macrophages play a critical role in host immune defense against bacterial infections. Our previous study demonstrated that oxalate, an important component of the most common type of kidney stone, impairs monocyte cellular bioenergetics and redox homeostasis. The objective of this study was to investigate whether oxalate compromises macrophage metabolism, redox status, anti-bacterial response, and immune response. Monocytes (THP-1, a human monocytic cell line) were exposed to sodium oxalate (soluble oxalate; 50 µM) for 48 hours prior to being differentiated into macrophages. Macrophages were subsequently exposed to calcium oxalate crystals (50 µM) for 48 hours followed by UPEC (MOI 1:2 or 1:5) for 2 hours. Peritoneal macrophages and bone marrow-derived macrophages (BMDM) from C57BL/6 mice were also exposed to oxalate. THP-1 macrophages treated with oxalate had decreased cellular bioenergetics, mitochondrial complex I and IV activity, and ATP levels compared to control cells. In addition, these cells had a significant increase in mitochondrial and total reactive oxygen species levels, mitochondrial gene expression, and pro-inflammatory cytokine (i.e. Interleukin-1β, IL-1β and Interleukin-6, IL-6) mRNA levels and secretion. In contrast, oxalate significantly decreased the mRNA levels and secretion of the anti-inflammatory cytokine, Interleukin-10 (IL-10). Further, oxalate increased the bacterial burden of primary macrophages. Our findings demonstrate that oxalate compromises macrophage metabolism, redox homeostasis, and cytokine signaling leading to a reduction in anti-bacterial response and increased infection. These data highlight a novel role of oxalate on macrophage function.

Post-death Vesicles of Senescent Bone Marrow Mesenchymal Stromal Polyploids Promote Macrophage Aging and Breast Cancer

“…Such aging-BMSC induced messages may undergo specific enhancement during the terminal stage of chronic cell death in aging stromal tissues, different from the biological function induced by instant free mtDNA not protected by membraned vesicles (42) and released from acute cell death after stress-induced senescence and apoptosis (31, 32, 43). Thus, instead of acute proinflammatory response in the local tissue induced by SASP, cellular redox imbalance induced by the SPSB-targeted distant tissues may accelerate organ degenerative conditions, leading to immune cell senescence and cancer initiation and progression (44) which may be particularly critical in transforming stem cells in breast cancer progression (35). The concept of SPSB-distant signal delivery of mtDNA and redox-related OXPHOS elements concur with the report that circulating EVs of aged animals contain a higher level of ROS than the young animal (45).…”

Oxalate disrupts monocyte and macrophage cellular function via Interleukin-10 and mitochondrial reactive oxygen species (ROS) signaling

“…THP-1 monocytes (a human monocytic cell line) were cultured in RPMI 1640 medium (cat # A1049101, ThermoFisher Scientific, Waltham, MA) supplemented with 10% FBS (cat# A5256801, ThermoFisher Scientific) and 20 μM β-mercaptoethanol (cat# M7522, Sigma Aldrich, St. Louis, MO) at 37 °C in a CO 2 incubator before treatment and during experiments. Monocytes were treated with oxalate (50 μM) with or without IL-10 (40 μg/mL) or MitoQ (200 nM) for 24 h. For additional experiments with macrophages, THP-1 monocytes were treated with NaOx (50 μM) for 24 h and then differentiated into macrophages using 200 nM Phorbol 12-myristate 13-acetate (PMA, cat #P8139) for 48 h [ 29 ]. The macrophages were allowed to rest for 24 h in fresh RPMI complete media without PMA before being treated with CaOx crystals (50 μM) for 48 h with or without IL-10 (40 ng/mL) and MitoQ (100 nM).…”

“…In addition, we have demonstrated that a single moderate dietary oxalate load equivalent to consumption of a spinach salad induces nanocrystalluria and alters metabolism to varying degrees in circulating monocytes isolated from healthy subjects [ 27 , 28 ]. We have also shown that oxalate exposure impairs cellular bioenergetics, redox homeostasis, and immune response in macrophages [ 29 ]. Others have reported that CaOx crystals induce the differentiation of monocytes into M1 pro-inflammatory macrophages [ 30 ].…”

Amoxicillin modulates gut microbiota to improve short-term high-fat diet induced pathophysiology in mice

“…Mice peritoneal macrophages (PM) were isolated from the peritoneal cavity as mentioned in our previous studies [90,91]. RBCs were removed from macrophages by using the RBC lysis buffer followed by washing with 1X PBS.…”