ABSTRACT
Objective To investigate the effect of 1 μmol/L and 10 μmol/L all trans retinoic acid（ATRA） on bone morphogenetic protein 9（BMP9）-induced maturation and differentiation of hepatic progenitor cells. Methods BMP9, BMP9 + 1 μmol/L ATRA and BMP9 + 10 μmol/L ATRA acted on HP14-19, respectively. The expression of albumin-drive gussid（LAB-Glus） was detected by luciferase reporter gene. The mRNA levels of ALB, cytokeratin 18（CK18）, tyrosine aminotransferase（TAT）, apolipoprotein B（ApoB） were detected by Real-time PCR. The expressions of ALB and uridine diphosphate glucuronosyltransferase 1 A（UGT1 A） were detected by immunofluorescence. Periodic acid-schiff（PAS） staining and indocyanine green（ICG） uptake assay were used to detect the metabolism and glycogen synthesis of hepatocytes. Real-time PCR and Western blotting were used to detect the expression of retinoic acid receptor（RAR）α, RARβ、RARγ and BMP9 signal related molecules Samd1, Samd 5 and Samd 8. Ad-siRARα、Ad-siRARβ、Ad-siRARγ infected cells were treated with BMP9+10 μmol/L ATRA, the cell morphology and PAS staining result were observed, the mRNA levels of ALB, CK18, TAT and ApoB were detected by Real-time PCR. Results BMP9 could significantly induce the maturation and differentiation of HP14-19 cells. The morphology of HP14-19 cells looked like polygonal paving stone. The expressions of ALB, CK18, ApoB and UGT1 A were significantly up-regulated. Some cells had the function of metabolic detoxification and glycogen synthesis. Compared with the BMP9 group, BMP9+1 μmol/L ATRA group had more mature morphology and larger volume. The expressions of Alb, CK18, ApoB and UGT1 A were up-regulated significantly（P＜0.05）. The number of ICG and PAS positive cells increased. Compared with the BMP9+1 μmol/L ATRA group, BMP9 + 10 μmol/L ATRA group showed long spindle, spindle and polygonal shapes, and the expression of hepatocyte related markers decreased, and the number of ICG and PAS positive cells decreased. ATRA（1 μmol/L） significantly increased the expression of RARα, RARβ and RARγ. Compared with the 1 μmol/L ATRA group, 10 μmol/L ATRA group only increased the expression of RARα. BMP9 did not affect the expression levels of Samd1, Samd5 and Samd8, but up-regulated their phosphorylation. Ad-siRARα could improve cell morphology and PAS staining induced by 10 μmol/L ATRA, while increased the expression of Alb and CK18（P＜0.05）. Conclusion ATRA（1 μmol/L） can promote the maturation and differentiation of hepatic progenitor cells（HPCs） induced by BMP9, while 10 μmol/L ATRA can weaken the differentiation of hepatic progenitor cells. Excessive ATRA may over activate RARα signal to affect the differentiation of hepatic progenitor cells.
ABSTRACT
The hereditary spastic paraplegias (HSPs or SPGs) are clinically and genetically highly heterogeneous neurodegenerative disorders mainly characterized by progressive spasticity and weakness in the lower limbs. The inheritance mode includes autosomal dominant(AD-HSP), autosomal recessive(AR-HSP) and X-linked recessive(XR-HSP). Thirty-five loci have been mapped with 17 disease-associated genes identified. SPG4 and SPG7 are the common subtypes in the AD-HSP and AR-HSP, respectively. The authors briefly review the function of spastin (SPG4) and paraplegin (SPG7), both of which belong to AAA ATPases family, and the recent progress of the study on the pathogenesis of HSPs.