S100 Calcium-Binding Protein P Secreted from Megakaryocytes Promotes Osteoclast Maturation

S100P binds to RAGE and activates ERK/NF-κB signaling to promote osteoclast differentiation and activity

S100 calcium-binding protein P (S100P) is a secretory protein that is expressed in various healthy tissues and tumors. Megakaryocyte-secreted S100P promotes osteoclast differentiation and function; however, its receptor and cellular signaling in osteoclasts remain unclear. Receptor for advanced glycation end products (RAGE), which is the receptor for S100P on cancer cells, was expressed in osteoclast precursors, and S100P-RAGE binding was confirmed through co-immunoprecipitation. Additionally, the phosphorylation of ERK and NF-κB was increased in S100P-stimulated osteoclast precursors but was inhibited by addition of the RAGE antagonistic peptide (RAP). S100P-induced osteoclast differentiation and excessive bone resorption activity were also reduced by the addition of RAP. This study demonstrates that S100P, upon binding with RAGE, activates the ERK and NF-κB signaling pathways in osteoclasts, leading to increased cell differentiation and bone resorption activity.

A comprehensive coding and microRNA transcriptome of vertebral bone in postlarvae and juveniles of Senegalese sole (Solea senegalensis)

Understanding vertebral bone development is essential to prevent skeletal malformations in farmed fish related to genetic and environmental factors. This is an important issue in Solea senegalensis, with special impact of spinal anomalies in postlarval and juvenile stages. Vertebral bone transcriptomics in farmed fish mainly comes from coding genes, and barely on miRNA expression. Here, we used RNA-seq of spinal samples to obtain the first comprehensive coding and miRNA transcriptomic repertoire for postlarval and juvenile vertebral bone, covering different vertebral phenotypes and egg-incubation temperatures related to skeleton health in S. senegalensis. Coding genes, miRNA and pathways regulating bone development and growth were identified. Differential transcriptomic profiles and suggestive mRNA-miRNA interactions were found between postlarvae and juveniles. Bone-related genes and functions were associated with the extracellular matrix, development and regulatory processes, calcium binding, retinol and lipid metabolism or response to stimulus, including those revealed by the miRNA targets related to signaling, cellular and metabolic processes, growth, cell proliferation and biological adhesion. Pathway enrichment associated with fish skeleton were identified when comparing postlarvae and juveniles: growth and bone development functions in postlarvae, while actin cytoskeleton, focal adhesion and proteasome related to bone remodeling in juveniles. The transcriptome data disclosed candidate coding and miRNA gene markers related to bone cell processes, references for functional studies of the anosteocytic bone of S. senegalensis. This study establishes a broad transcriptomic foundation to study healthy and anomalous spines under early thermal conditions across life-stages in S. senegalensis, and for comparative analysis of skeleton homeostasis and pathology in fish and vertebrates.

The RAGE signaling in osteoporosis

Osteoporosis (OP), characterized by an imbalance of bone remodeling between formation and resorption, has become a health issue worldwide. The receptor for advanced glycation end product (RAGE), a transmembrane protein in the immunoglobin family, has multiple ligands and has been involved in many chronic diseases, such as diabetes and OP. Increasing evidence shows that activation of the RAGE signaling negatively affects bone remodeling. Ligands, such as advanced glycation end products (AGEs), S100, β-amyloid (Aβ), and high mobility group box 1 (HMGB1), have been well documented that they may negatively regulate the proliferation and differentiation of osteoblasts and positively stimulate osteoclastogenesis by activating the expression of RAGE. In this review, we comprehensively discuss the structure of RAGE and its biological functions in the pathogenesis of OP. The research findings suggest that RAGE signaling has become a potential target for the therapeutic management of OP.

Secretome-based acellular therapy of bone marrow-derived mesenchymal stem cells in degenerative and immunological disorders: A narrative review

The bone marrow (BM) plays a pivotal role in homeostasis by supporting hematopoiesis and immune cells' activation, maturation, interaction, and deployment. "BMSC-derived secretome" refers to the complete repertoire of secreted molecules, including nucleic acids, chemokines, growth factors, cytokines, and lipids from BM-derived mesenchymal stem cells (BMSCs). BMSC-derived secretomes are the current molecular platform for acellular therapy. Secretomes are highly manipulable and can be synthesised in vast quantities using commercially accessible cell lines in the laboratory. Secretomes are less likely to elicit an immunological response because they contain fewer surface proteins. Moreover, the delivery of BMSC-derived secretomes has been shown in numerous studies to be an effective, cell-free therapy method for alleviating the symptoms of inflammatory and degenerative diseases. As a result, secretome delivery from BMSCs has the same therapeutic effects as BMSCs transplantation but may have fewer adverse effects. Additionally, BMSCs' secretome has therapeutic promise for organoids and parabiosis studies. This review focuses on recent advances in secretome-based cell-free therapy, including its manipulation, isolation, characterisation, and delivery systems. The diverse bioactive molecules of secretomes that successfully treat inflammatory and degenerative diseases of the musculoskeletal, cardiovascular, nervous, respiratory, reproductive, gastrointestinal, and anti-ageing systems were also examined in this review. However, secretome-based therapy has some unfavourable side effects that may restrict its uses. Some of the adverse effects of this modal therapy were briefly mentioned in this review.

Histoplasma capsulatum modulates the immune response, affects proliferation and differentiation, and induces apoptosis of mesenchymal stromal cells

Mesenchymal stromal cells (MSC) have been widely used not only for tissue regeneration but also for the treatment of various diseases; however, it has been shown that infection of MSCs by different pathogens can attenuate their intrinsic immunomodulatory properties, affecting the proliferation and differentiation of these cells. Currently, the mechanisms by which MSCs respond to pathogen invasion are poorly understood. Therefore, the objective of the present study was to determine if the infection of bone marrow-derived MSCs, with yeasts of the pathogenic fungus Histoplasma capsulatum affects the activation, differentiation and/or proliferation of the MSCs. The results indicate that MSCs have the ability to phagocytose H. capsulatum yeasts but do not exert a notable antifungal effect. On the contrary, the infection of the MSCs with this fungal pathogen not only modulates the expression of inflammatory mediators by a mechanism dependent on TLR2, TLR4 and Dectin-1 but also affects the viability and differentiation capacity of the MSCs. These findings suggest that infection of MSCs by H. capsulatum could not only affect haematopoiesis but also modulate the immune response in the infected host and, furthermore, these MSCs could provide a niche for the fungus, allowing it to persist and evade the immune response of the host.

Calcium-binding protein S100P is a new target gene of MACC1, drives colorectal cancer metastasis and serves as a prognostic biomarker

Background

The metastasis inducing gene MACC1 is a prognostic and predictive biomarker for metastasis in several cancers. Its mechanism of inducing metastasis includes the transcriptional control of other cancer-related target genes. Here, we investigate the interplay with the metastasis driver S100P in CRC progression.

Methods

MACC1-dependent S100P expression was analysed by qRT-PCR. The binding of MACC1 to the S100P promoter was determined by ChIP. Alterations in cell proliferation and motility were determined by functional in vitro assays. In vivo metastasis after intrasplenic transplantation was assessed by bioluminescence imaging and evaluation of tumour growth and liver metastasis. The prognostic value of S100P was determined in CRC patients by ROC-based Kaplan–Meier analyses.

Results

Expression of S100P and MACC1 correlated positively in CRC cells and colorectal tumours. MACC1 was found binding to the S100P promoter and induces its expression. The overexpression of S100P increased proliferation, migration and invasion in vitro and significantly induced liver metastasis in vivo. S100P expression was significantly elevated in metachronously metastasising CRC and was associated with shorter metastasis-free survival.

Conclusions

We identified S100P as a transcriptional target gene of MACC1. Expression of S100P increases the metastatic potential of CRC cells in vitro and in vivo, and serves as a prognostic biomarker for metastasis-free survival of CRC patients, emphasising novel therapeutic interventions targeting S100P.

Bioinformatics of Differentially Expressed Genes in Phorbol 12-Myristate 13-Acetate-Induced Megakaryocytic Differentiation of K562 Cells by Microarray Analysis

Megakaryocytes are large hematopoietic cells present in the bone marrow cavity, comprising less than 0.1% of all bone marrow cells. Despite their small number, megakaryocytes play important roles in blood coagulation, inflammatory responses, and platelet production. However, little is known about changes in gene expression during megakaryocyte maturation. Here we identified the genes whose expression was changed during K562 leukemia cell differentiation into megakaryocytes using an Affymetrix GeneChip microarray to determine the multifunctionality of megakaryocytes. K562 cells were differentiated into mature megakaryocytes by treatment for 7 days with phorbol 12-myristate 13-acetate, and a microarray was performed using RNA obtained from both types of cells. The expression of 44,629 genes was compared between K562 cells and mature megakaryocytes, and 954 differentially expressed genes (DEGs) were selected based on a p-value < 0.05 and a fold change >2. The DEGs was further functionally classified using five major megakaryocyte function-associated clusters—inflammatory response, angiogenesis, cell migration, extracellular matrix, and secretion. Furthermore, interaction analysis based on the STRING database was used to generate interactions between the proteins translated from the DEGs. This study provides information on the bioinformatics of the DEGs in mature megakaryocytes after K562 cell differentiation.