Monocytic microparticles (mMP) are microparticles derived from human monocytes either under in vivo or in vitro conditions. The size of mMP is between 0.1 and 1.0 μm. Apart from the size range, mMPs are also identified based on phosphatidylserine and CD14 expression on their surface, though this is not always the case. Monocytic MP are critical players in inflammation, endothelial cell function, and blood coagulation. They exhibit dual function by either helping the progression of such conditions or limiting it, depending on certain factors. Furthermore, the numbers of mMP are elevated in some autoimmune diseases, infectious diseases, and metabolic disorders. However, it is unknown whether mMP play an active role in these diseases or are simply biomarkers. The mechanism of mMP modulation is yet to be identified. In this review, we highlight the mechanism of mMP formation and the roles that they play in inflammation, blood coagulation, and different disease settings.
Hypoxia inducible factor (HIF)-prolyl hydroxylase (PHD) inhibitors are shown to be protective in several models of inflammatory bowel disease (IBD). However, these non-selective inhibitors are known to inhibit all the three isoforms of PHD, i.e. PHD-1, PHD-2 and PHD-3. In the present report, we investigated the associated changes in levels of PHDs during the development and recovery of chemically induced colitis in mice. The results indicated that in the experimental model of murine colitis, levels of both, PHD-1 and PHD-2 were found to be increased with the progression of the disease; however, the level of PHD-3 remained the same in group of healthy controls and mice with colitis. Thus, the findings advocated that inhibitors, which inhibited all three isoforms of PHD could not be ideal therapeutics for IBD since PHD-3 is required for normal gut function. Hence, this necessitates the development of new compounds capable of selectively inhibiting PHD-1 and PHD-2 for effective treatment of IBD.
Hypophyllanthin (HYP) and niranthin (NIR) are major lignans in Phyllanthus spp. and have been shown to possess strong anti-inflammatory activity. In this study, we investigated the anti-inflammatory effects and the underlying molecular mechanisms of HYP and NIR in in vitro cellular model of LPS-induced U937 macrophages. The effects of HYP and NIR on the production of prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were measured by using ELISA, Western blot, and qRT-PCR. The expressions of signaling molecules related to nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs), and phosphatidylinositol 3'-kinase-Akt (PI3K-Akt) signaling pathways were examined. The role of NF-κB, MAPKs, and Akt signaling pathways was confirmed by using specific inhibitors (BAY 11-7082, U0126, SB202190, SP600125, and LY294002) mediated suppression of TNF-α and COX-2 production. HYP and NIR significantly inhibited the protein and gene levels of COX-2 as well as the downstream signaling products of PGE2, TNF-α, and IL-1β. HYP and NIR also suppressed the inhibitors of kappa B (IκB), IkB kinases (Ikkα/β), NF-κB phosphorylation, and IκB degradation. HYP suppressed the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 while NIR only suppressed JNK and ERK but did not have effect on p38. These results demonstrate that HYP and NIR downregulated COX-2, TNF-α, and IL-1β gene expressions in U937 macrophages by interfering with the activation of NF-κB, MAPKs, and Akt. In conclusion, these lignans have potential to be developed as anti-inflammatory agents targeting the NF-κB, MAPK, and PI3K-Akt pathways.