Proteoglycan 4 regulates macrophage function without altering atherosclerotic lesion formation in a murine bone marrow-specific deletion model

Potential Role of mRNAs and LncRNAs in Chronic Intermittent Hypoxia Exposure-Aggravated Atherosclerosis

“…Both mRNA Prg4 and lncRNA NONMMUT003096were upregulated in CIH 8W group compared with Nor 8W ( Table 2). Previous research show the Prg4 expression was increased in murine initial atherosclerotic lesions, and deletion of Prg4 in macrophage had effect on both cellular cholesterol metabolism and inflammation in vitro (Nahon et al, 2018). Our results demonstrate that Prg4 and NONMMUT003096 had both co-localization and co-expression relationships.…”

Proteoglycan 4: From Mere Lubricant to Regulator of Tissue Homeostasis and Inflammation

“…Originally perceived solely as a lubricating molecule in these diverse tissues, we suggest that in addition to reducing friction between biological surfaces a growing body of literature suggests that PRG4 has the ability to interact with immune cells. This implies that PRG4 may play key roles in immunity and/or the regulation of the inflammatory response . In this manuscript, we introduce known lubrication functions of PRG4 and present a hypothesis supported by the literature that PRG4 acts a buffer in the inflammatory response.…”

“…PRG4 has been shown to regulate the inflammatory response, both systemically and at a cellular level, through interaction with cell surface receptors of neutrophils and macrophage . In the presence of pro‐inflammatory cytokines such as interleukin‐1β (IL‐β) and tumor necrosis factor α (TNFα), the expression of PRG4 in cartilage (ex vivo) is significantly decreased.…”

“…Prg4 −/− mice also present with changes to the articular cartilage, but also present with increased damage to the ocular surface staining, thus suggesting that PRG4 may play a key role in ocular surface boundary lubrication, and may prevent corneal damage under normal homeostatic conditions . Furthermore, in vivo pre‐clinical animal studies and ex vivo studies on human tissues have demonstrated that altered expression and/or function of PRG4 has been associated with acute and chronic diseases including osteoarthritis (OA), rheumatoid arthritis (RA), Sjogren syndrome, atherosclerosis, and pericarditis . In most of these previous studies, the function by which PRG4 promotes tissue homeostasis or its absence contributes to increased tissue damage has been through a reduction in friction.…”

Lubricin Contributes to Homeostasis of Articular Cartilage by Modulating Differentiation of Superficial Zone Cells

“…In recent years, it has been reported that Prg4‐KO mice exhibit more severe arteriosclerosis, reduced macrophage responsiveness to inflammation, and improved glucose tolerance compared with WT mice, suggesting that lubricin has various kinds of biological functions other than lubrication in articular joints. ( 35–37 ) Considering that lubricin is an extracellular protein, lubricin probably exerts its effects through binding to other extracellular proteins or cell surface proteins. Previous in vitro experiments have revealed that TLR2, 4, and 5, and CD44 are potent candidates for lubricin receptors.…”