Monocyte Chemotactic Protein-1 (MCP1) Accumulation in Human Osteoclast Precursor Cultures

MCP-5 suppresses osteoclast differentiation through Ccr5 upregulation

Human monocyte chemoattractant protein-1 (MCP-1) in mice has two orthologs, MCP-1 and MCP-5. MCP-1, which is highly expressed in osteoclasts rather than in osteoclast precursor cells, is an important factor in osteoclast differentiation. However, the roles of MCP-5 in osteoclasts are completely unknown. In this study, contrary to MCP-1, MCP-5 was downregulated during receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation and was considered an inhibitory factor in osteoclast differentiation. The inhibitory role of MCP-5 in osteoclast differentiation was closely related to the increase in Ccr5 expression and the inhibition of IκB degradation by RANKL. Transgenic mice expressing MCP-5 controlled by Mx-1 promoter exhibited an increased bone mass because of a decrease in osteoclasts. This result strongly supported that MCP-5 negatively regulated osteoclast differentiation. MCP-5 also prevented severe bone loss caused by RANKL.

Salvia officinalis Improves Glycemia and Suppresses Pro-inflammatory Features in Obese Rats with Metabolic Syndrome

OBJECTIVES

Obesity is regarded as the main cause of metabolic diseases and a core factor for all-cause mortality in the general population, notably from cardiovascular disease. The majority of people with type 2 diabetes have obesity and insulin resistance. Some evidence indicates that an individual with obesity is approximately 10 times more likely to develop type 2 diabetes than someone with moderate body weight. One of the most significant therapeutic herbs, Salvia officinalis (Lamiaceae) (SAGE), possesses potent medicinal importance. The aim of this article was to evaluate the anti-diabetic and antiobesity activity of SAGEAE against HFD-induced obesity in rats.

METHODS

Thirty adult albino rats were randomly divided into five equal groups: control, High-fat Diet (HFD) administrated rats, HFD + Salvia officinalis Aqueous Extract (SAGEAE) (150 mg/kg.bw.), HFD + SAGEAE (300 mg/kg.bw.) and HFD + metformin (500 mg/kg.bw.). Body weight, plasma biochemical parameters, oxidative stress, inflammatory indicators, hepatic Phosphoenolpyruvate Carboxykinase 1 (PCK1), Glucokinase (GK), brain Leptin Receptor (LepRb), Glucose Transporter-4 (GLUT4), Sirtuin 1 (SIRT1) and mRNA33-5P gene signalling mRNA levels were all assessed after 8 weeks. A histological examination of the liver was also performed to check for lipid accumulation.

RESULTS

The administration of HFD resulted in increased body weight, glucose, insulin, leptin, Total Cholesterol (TC), Triglycerides (TG), Thiobarbaturic Acid Reactive Substances (TBARS), Monocyte Chemoattractant Protein-1 (MCP1), Interleukine-6 (IL-6) and tumor necrosis factor-α (TNF- α) as well as hepatic PCK1, brain LepRb and adipose tissue mRNA33-5P gene expression. However, our findings revealed a significant reduction in adiponectin, High-density Lipoproteincholesterol (HDL-C), reduced glutathione (GSH) and Superoxide Dismutase (SOD) levels as well as the expression of hepatic GK and adipose tissue SIRT1 and GLUT4 genes. Also, administration of SAGEAE significantly normalized body weight, glucose, insulin, leptin, adiponectin, TC, TG, HDL-C, TBARs, SOD, IL-6, MCP-1 and TNF-α in plasma and liver tissue of HFD-treated rats. On the other hand, PCK1, GK, LepRb, SIRT1, GLUT4 and mRNA33-5P gene expression was enhanced in obese rats when administrated with SAGEAE. Histological and US studies support the biochemical, PCR and electrophoretic results.

CONCLUSION

The findings imply that SAGEAE could be used as a new pharmaceutical formula in the treatment of obesity.

MCP-1-Loaded Poly(l-lactide-co-caprolactone) Fibrous Films Modulate Macrophage Polarization toward an Anti-inflammatory Phenotype and Improve Angiogenesis

Tissue engineering approaches such as the electrospinning technique can fabricate nanofibrous scaffolds which are widely used for small-diameter vascular grafting. However, foreign body reaction (FBR) and lack of endothelial coverage are still the main cause of graft failure after the implantation of nanofibrous scaffolds. Macrophage-targeting therapeutic strategies have the potential to address these issues. Here, we fabricate a monocyte chemotactic protein-1 (MCP-1)-loaded coaxial fibrous film with poly(l-lactide-co-ε-caprolactone) (PLCL/MCP-1). The PLCL/MCP-1 fibrous film can polarize macrophages toward anti-inflammatory M2 macrophages through the sustained release of MCP-1. Meanwhile, these specific functional polarization macrophages can mitigate FBR and promote angiogenesis during the remodeling of implanted fibrous films. These studies indicate that MCP-1-loaded PLCL fibers have a higher potential to modulate macrophage polarity, which provides a new strategy for small-diameter vascular graft designing.

Single-cell RNA analysis of chemokine expression in heterogeneous CD14+ monocytes with lipopolysaccharide-induced bone resorption

Lipopolysaccharide (LPS)-induced bone resorption has normally been found in inflammatory bone diseases, but the underlying mechanism is currently unclear. Since LPS binds to CD14 and activates Toll-like receptor 4 (TLR4) in monocytes, the present study focused on CD14⁺ monocytes and observed their responses after LPS treatment during the progression of local bone destruction. CD14⁺ monocytes were obtained from human peripheral blood mononuclear cells (PBMCs) by magnetic cell separation (MACS), and their classification was confirmed by fluorescence-activated cell sorting (FACS). Single-cell RNA sequencing (scRNA-seq) was further utilized to analyze their subpopulations, and the results showed that physiological CD14⁺ monocytes were heterogeneous and divided into 6 subsets, that could be easily agitated. After priming with a suitable concentration of LPS, heterogeneous CD14⁺ monocytes became pathological and expressed a large number of chemokines as a "cascade effect". Some of these chemokines have been validated in an animal model of mouse calvarial bone invasion. Taken together, our research has linked enhanced chemokine expression with stimulation of heterogeneous CD14⁺ monocytes, and indicated that inflammatory responses caused by microbiome infection are responsible for the recruitment and mobilization of CD14⁺ monocytes into bone resorption sites, which may explain the pathogenesis of LPS-associated bone diseases.