Proteomic insights into protostane triterpene biosynthesis regulatory mechanism after MeJA treatment in Alisma orientale (Sam.) Juz.

Protostane triterpenes in Alisma orientale (Sam.) Juz. have unique structural features with distinct pharmacological activities. Previously we have demonstrated that protostane triterpene biosynthesis could be regulated by methyl jasmonate (MeJA) induction in A. orientale. Here, proteomic investigation reveals the MeJA mediated regulation of protostane triterpene biosynthesis. In our study, 281 differentially abundant proteins were identified from MeJA-treated compared to control groups, while they were mainly associated with triterpene biosynthesis, α-linolenic acid metabolism, carbohydrate metabolism and response to stress/defense. Key enzymes 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), squalene epoxidase (SE), oxidosqualene cyclase (OSC) and cytochrome P450s which potentially involved in protostane triterpene biosynthesis were significantly enriched in MeJA-treated group. Basic Helix-loop-helix (bHLH), MYB, and GRAS transcription factors were enhanced after MeJA treatment, and they also improved the expressions of key enzymes in Mevalonate pathway and protostane triterpene. Then, MeJA also could increase the expression of α-galactosidase (α-GAL), thereby promoting carbohydrate decomposition, and providing energy and carbon skeletons for protostane triterpene precursor biosynthesis. As well, exogenous MeJA treatment upregulated 13-lipoxygenase (13-LOX), allene oxide synthase (AOS) and allene oxide cyclase (AOC) involved in α-linolenic acid metabolism, leading to the accumulation of endogenous MeJA and activation of the protostane triterpene biosynthesis transduction. Finally, MeJA upregulated stress/defence-related proteins, as to enhance the defence responses activity of plants. These results were further verified by quantitative real-time PCR analysis of 19 selected genes and content analysis of protostane triterpene. The results provide some new insights into the role of MeJA in protostane triterpene biosynthesis.

Long non-coding RNA LINC01106 regulates colorectal cancer cell proliferation and apoptosis through the STAT3 pathway / 南方医科大学学报

OBJECTIVE@#To investigate the expression of LINC01106 in colorectal cancer and its role in regulating the proliferation and apoptosis of colorectal cancer cells.@*METHODS@#We analyzed the data of LINC01106 expression levels in tumor tissues and normal tissues of patients with colorectal cancer in TCGA database and explored the association of LINC01106 expression level with the prognosis of the patients. Colorectal cancer SW480 cell lines with LINC01106 knockdown or overexpression were established, and their proliferation and apoptosis relative to the parental cells were evaluated using CCK-8 assay and flow cytometry, respectively. The expressions of p-STAT3, STAT3, and Bcl-2 in the cells were detected by immunoblotting. Nude mouse models bearing xenografts of SW480 cells with LINC01106 knockdown or na?ve SW480 cells were established to observe the effect of LINC01106 knockdown on the growth of SW480 cells .@*RESULTS@#Analysis of the data from TCGA database showed that the expression level of LINC01106 was significantly higher in colorectal cancer tissues than in normal tissues, and LINC01106 expression level was significantly related to the prognosis of the patients ( < 0.05). Knockdown of LINC01106 significantly inhibited the proliferation and promoted apoptosis of SW480 cells ( < 0.05), while LINC01106 overexpression significantly promoted proliferation of the cells. LINC01106 knockdown in SW-480 cells obviously lowered the expressions of p- STAT3 and Bcl-2 and suppressed the growth of the xenograft in nude mice.@*CONCLUSIONS@#LINC01106 is significantly up-regulated in colorectal cancer tissue and is related to the prognosis of the patients. LINC01106 can regulate the proliferation and apoptosis of SW480 cells through STAT3/Bcl-2 signaling and may serve as a potential marker for the diagnosis and prognostic evaluation of colorectal cancer.

Src kinase inhibitor PP2 protects rat astrocytes from hypoxia/reoxygenation injury in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of Src kinase inhibitor PP2 on hypoxia/reoxygenation (H/R) injury in rat astrocytes in vitro.</p><p><b>METHODS</b>In vitro cultured rat astrocytes were exposed to hypoxia for 8 h followed by reoxygenation for 24 h with or without pretreatment with PP2 (10 µmol/L) for 24 h before H/R injury. MTT assay and flow cytometry were used to detect the viability and apoptosis of the exposed astrocytes, respectively, and the protein expressions of Src, Bax, and Bcl-2 in the cells were determined using Western blotting.</p><p><b>RESULTS</b>PP2 pretreatment significantly increased the viability and decreased the apoptosis rate of rat astrocytes exposed to H/R injury (P<0.01). Western blotting showed that H/R injury caused increased expression of Src kinase, which was lowered by PP2 pretreatment. The ratio of Bax/bcl-2 in the astrocytes increased after H/R injury, and was significantly decreased by PP2 pretreatment (P<0.01).</p><p><b>CONCLUSION</b>PP2 protects rat astrocytes from H/R injury possibly by inhibiting the expression of Src kinase and activating the anti-apoptotic mechanisms in the cells.</p>

Expression of connexin 43 and functional modulation of gap junction in neonatal rat astrocytes in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the expression of connexin 43 (Cx43) protein and explore the functional modulation of gap junction intercellular communication in astrocytes.</p><p><b>METHODS</b>Cultured neonatal SD rat astrocytes were divided into normal control group, all-trans retinoic acid (ATRA) group (treated with 10 µmol/L ATRA for 24 h) and oleamide group (treated with 25 µmol/L oleamide for 2 h). Western blotting and immunofluorescence assay were used to detect total cellular Cx43 protein expression and Cx43 expression on the surface of the astrocytes, respectively. Parachute assay was used to evaluate the functional changes of gap junction intercellular communication of the astrocytes.</p><p><b>RESULTS</b>Compared with the normal control cells, ATRA treatment resulted in a significantly increased expression of total Cx43 protein in the astrocytes (P<0.01), and oleamide significantly suppressed its expression (P<0.01). Similarly, ATRA obviously enhanced while oleamide suppressed Cx43 protein expression on the surface of the astrocytes. The gap junction intercellular communication of the astrocytes was enhanced by ATRA (P<0.01) and inhibited by oleamide (P<0.01).</p><p><b>CONCLUSION</b>ATRA and oleamide can modulate gap junction intercellular communication of the astrocytes possibly by regulating the expression of Cx43 protein.</p>