miR-199b-5p is up-regulated significantly during the osteogenesis process in human bone marrow stromal cells (BMSCs). Inhibiting miR-199b-5p notably reduces while over-expressing miR-199b-5p promotes the BMSCs osteoblast differentiation, suggested by the alternations of osteogenic genes expression, ALP activity and the ARS-stained mineral nodules. miR-199b-5p exerts its role in BMSC osteogenesis most probably through the GSK-3β/β-catenin signaling pathway. In conclusion, the present study revealed for the first time that miR-199b-5p plays a positive role in osteoblast differentiation.

Beta-naphthoflavone (BNF, DB06732) is an agonist of aryl hydrocarbon receptor (AhR) and a putative chemotherapeutic agent that has antitumor activity against mammary carcinomas in vivo. However, the mechanism by which BNF exerts this antitumor effect remains unclear. Thus, we explored mechanisms of BNF's antitumor effects in human breast cancer cells. This study showed that BNF suppressed cell proliferation and induced cell cycle arrest in the G0/G1 phase with downregulation of cyclin D1/D3 and CDK4 and upregulation of p21(Cip1/Waf1), leading to a senescence-like phenotype in estrogen receptor (ER)-positive MCF-7 cells, but not in ER-negative MDA-MB-231 cells. In addition, BNF inhibited PI3K/AKT signaling, and the PI3K inhibitor, LY294,002, exhibited the same inhibitory effects on cyclinD1/D3, CDK4 and the cell cycle as BNF. Interestingly, BNF activated mitogen-activated protein kinase-extracellular signal-regulated kinase (MAPK-ERK) signaling, and more notably, MEK inhibitor PD98059 significantly blocked the BNF-induced cell cycle arrest and upregulation of p21(Cip1/Waf1). Furthermore, specific ERα and AhR siRNA studies indicate that ERα is required in BNF-induced p21(Cip1/Waf1) expression, and BNF-mediated cell cycle arrest and modulation of AKT and ERK signaling is AhR-dependent. Taken together, AhR-dependent inhibition of the PI3K/AKT pathway, activation of MAPK/ERK and modulation of ERα is a novel mechanism underlying BNF-mediated antitumor effects in breast cancer, which may represent a promising strategy to be exploited in future clinical trials.

Skeletal complications are common features of neonatal-onset multisystem inflammatory disease (NOMID), a disorder caused by NLRP3-activating mutations. NOMID mice in which NLRP3 is activated globally exhibit several characteristics of the human disease, including systemic inflammation and cartilage dysplasia, but the mechanisms of skeletal manifestations remain unknown. In this study, we find that activation of NLRP3 in myeloid cells, but not mesenchymal cells triggers chronic inflammation, which ultimately, causes growth plate and epiphyseal dysplasia in mice. These responses are IL-1 signaling-dependent, but independent of PARP1, which also functions downstream of NLRP3 and regulates skeletal homeostasis. Mechanistically, inflammation causes severe anemia and hypoxia in the bone environment, yet down-regulates the HIF-1α pathway in chondrocytes, thereby promoting the demise of these cells. Thus, activation of NLRP3 in hematopoietic cells initiates IL-1β-driven paracrine cascades, which promote abnormal growth plate development in NOMID mice.

PSP-regulated gene expression and cytokine secretion related to TLR signaling pathway in human PBMCs. Especially, TRAM-TRIF-TRAF6 subsignaling pathway of TLR may be one of the key associated signaling pathways in the immunomodulation of PSP.

The G protein-coupled estrogen receptor (GPER) has been implicated in the regulation of smooth muscle cell (SMC) proliferation. The GPER selective agonist G-1 has been a useful tool for exploring the biological roles of GPER in a variety of experimental settings, including SMC proliferation. The present study, originally designed to investigate cellular and signaling mechanisms underlying the regulatory role of GPER in vascular SMC proliferation using G-1, unexpectedly revealed off-target effects of G-1. G-1(1-10 μM) inhibited bromodeoxyuridine (BrdU) incorporation of human SMCs and caused G2/M cell accumulation. G-1 treatment also increased mitotic index concurrent with a decrease in phosphorylation of Cdk1 (Tyr 15) and an increase in phosphorylation of the mitotic checkpoint protein BuBR1. Furthermore, G-1 caused microtubule disruption, mitotic spindle damage, and tubulin depolymerization. G-1 induced cell apoptosis as indicated by the appearance of TUNEL-positive and annexin V-positive cells with enhanced cleavage of caspases 3 and 9. However, neither the GPER antagonist G-15 nor the MAPK kinase inhibitor PD98059 prevented these G-1 effects. Down-regulation of GPER or p44/42 MAPK with siRNA transfection also did not affect the G-1-induced apoptosis. We conclude that G-1 inhibits proliferation of SMCs through mechanisms involving mitotic arrest and apoptosis, independent of GPER and the MAPK pathway.