Phosphatidylinositol-specific phospholipase C can decrease Müller cell viability and suppress its phagocytic activity by modulating PI3K/AKT signaling pathway

Bacillus cereus endophthalmitis is a devastating eye infection that causes rapid blindness through the release of extracellular tissue-destructive exotoxins. The phagocytic and antibacterial functions of ocular cells are the keys to limiting ocular bacterial infections. In a previous study, we identified a new virulence gene, plcA-2 (different from the original plcA-1 gene), that was strongly associated with the plcA gene of Listeria monocytogenes. This plcA gene had been confirmed to play an important role in phagocytosis. However, how the Bc-phosphatidylinositol-specific phospholipase C (PI-PLC) proteins encoded by the plcA-1/2 genes affect phagocytes remains unclear in B. cereus endophthalmitis. Here, we found that the enzymatic activity of Bc-PI-PLC-A2 was approximately twofold higher than that of Bc-PI-PLC-A1, and both proteins inhibited the viability of Müller cells. In addition, PI-PLC proteins reduced phagocytosis of Müller cells by decreasing the phosphorylation levels of key proteins in the PI3K/AKT signaling pathway. In conclusion, we showed that PI-PLC proteins contribute to inhibit the viability of and suppress the phagocytosis of Müller cells, providing new insights into the pathogenic mechanism of B. cereus endophthalmitis.

The Synergistic Effect of Zuogui Pill and Eldecalcitol on Improving Bone Mass and Osteogenesis in Type 2 Diabetic Osteoporosis

Background and Objectives: The incidence of diabetic osteoporosis, an important complication of diabetes mellitus, is increasing gradually. This study investigated the combined effect of the Zuogui pill (ZGP) and eldecalcitol (ED-71), a novel vitamin D analog, on type 2 diabetic osteoporosis (T2DOP) and explored their action mechanism. Materials and Methods: Blood glucose levels were routinely monitored in db/db mice while inducing T2DOP. We used hematoxylin and eosin staining, Masson staining, micro-computed tomography, and serum biochemical analysis to evaluate changes in the bone mass and blood calcium and phosphate levels of mice. Immunohistochemical staining was performed to assess the osteoblast and osteoclast statuses. The MC3T3-E1 cell line was cultured in vitro under a high glucose concentration and induced to undergo osteogenic differentiation. Quantitative real-time polymerase chain reaction, Western blot, immunofluorescence, ALP, and alizarin red staining were carried out to detect osteogenic differentiation and PI3K-AKT signaling pathway activity. Results: ZGP and ED-71 led to a dramatic decrease in blood glucose levels and an increase in bone mass in the db/db mice. The effect was strongest when both were used together. ZGP combined with ED-71 promoted osteoblast activity and inhibited osteoclast activity in the trabecular bone region. The in vitro results revealed that ZGP and ED-71 synergistically promoted osteogenic differentiation and activated the PI3K-AKT signaling pathway. The PI3K inhibitor LY294002 or AKT inhibitor ARQ092 altered the synergistic action of both on osteogenic differentiation. Conclusions: The combined use of ZGP and ED-71 reduced blood glucose levels in diabetic mice and promoted osteogenic differentiation through the PI3K-AKT signaling pathway, resulting in improved bone mass. Our study suggests that the abovementioned combination constitutes an effective treatment for T2DOP.

miR-331-3p Inhibits Proliferation and Promotes Apoptosis of Nasopharyngeal Carcinoma Cells by Targeting elf4B-PI3K-AKT Pathway

BACKGROUND

The incidence of nasopharyngeal carcinoma is increasing gradually, but the pathogenesis is not completely clear. MicroRNA, a highly conserved endogenous noncoding small molecule RNA, plays an essential role in the regulation of gene expression and is a hotspot in cancer research worldwide.

OBJECTIVES

Although previous studies have confirmed that the abnormal expression of microRNAs is closely related to the progression of nasopharyngeal carcinoma, the role of miRNA-331-3p in nasopharyngeal carcinoma has not been studied. The purpose of this study was to explore the role and mechanism of miRNA-331-3p in the progression of nasopharyngeal carcinoma.

MATERIALS AND METHODS

Real-time quantitative reverse transcription polymerase chain reaction was performed to detect the expression of miRNA-331-3p in nasopharyngeal carcinoma clinical samples and cell lines (CNE-1 and 5-8F cells). After overexpression of miRNA-331-3p in CNE-1 cells, cell proliferation was measured by Cell Counting Kit-8 assay, cell invasion was detected by Transwell assay, and apoptosis was tested by flow cytometry. In addition, the dual-luciferase reporter assay was used to identify the target gene of miRNA-331-3p and Western blotting was performed to measure the relative protein expression.

RESULTS

The expression of miRNA-331-3p in nasopharyngeal carcinoma clinical samples and cells was decreased significantly. Overexpression of miRNA-331-3p markedly inhibited the proliferation and invasion of CNE-1 cells and promoted cell apoptosis. Moreover, overexpression of miRNA-331-3p reduced the expression of target gene elF4B, leading to inhibition of the phosphorylation of Phosphoinositide 3-kinase (PI3K) and Serine/ threonine kinase (AKT).

CONCLUSION

miRNA-331-3p inhibited cell proliferation and induced cell apoptosis in nasopharyngeal carcinoma by targeting elF4B gene and then blocked the PI3K-AKT signaling pathway.

SIGNIFICANCE

The role of miRNA-331-3p in the development of NPC and its mechanism provide new ideas for the treatment of nasopharyngeal carcinoma.

Effects of lycopene on vascular remodeling through the LXR-PI3K-AKT signaling pathway in APP/PS1 mice

Alzheimer's disease (AD) is the commonest neurodegenerative disease and, in recent years, studies have increasingly shown that vascular lesions are involved in the pathology of AD onset and progression. Many vascular changes precede the pathological changes and clinical symptoms of AD, and vascular lesions and AD have many common risk factors. Understanding the relationship between vascular factors and the pathological process of AD may help us to identify novel prevention and treatment strategies as well as delay disease progress. Previous studies have shown that lycopene has neuroprotective, antioxidant, and anticancer effects; however, the specific molecular mechanism mediating these effects remains unknown. In the present study, we found: 1) lycopene improved learning and memory in an AD mouse model; 2) lycopene inhibited amyloid plaque aggregation and neuroinflammation; and 3) lycopene induced LXR expression and activated the LXR-PI3K-AKT signaling pathway. Our findings suggest that promotion of neurogenesis and improvement of the functions of the neurovascular unit could be a novel direction for the development of AD therapies.