Dynamic changes of key metabolites during liver fibrosis in rats

BACKGROUND Fibrosis is the single most important predictor of significant morbidity and mortality in patients with chronic liver disease.Established non-invasive tests for monitoring fibrosis are lacking,and new biomarkers of liver fibrosis and function are needed.AIM To depict the process of liver fibrosis and look for novel biomarkers for diagnosis and monitoring fibrosis progression.METHODS CCl4 was used to establish the rat liver fibrosis model.Liver fibrosis process was measured by liver chemical tests,liver histopathology,and Masson’s trichrome staining.The expression levels of two fibrotic markers includingα-smooth muscle actin and transforming growth factorβ1 were assessed using immunohistochemistry and real-time polymerase chain reaction.Dynamic changes in metabolic profiles and biomarker concentrations in rat serum during liver fibrosis progression were investigated using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.The discriminatory capability of potential biomarkers was evaluated by receiver operating characteristic(ROC)curve analysis.RESULTS To investigate the dynamic changes of metabolites during the process of liver fibrosis,sera from control and fibrosis model rats based on pathological results were analyzed at five different time points.We investigated the association of liver fibrosis with 21 metabolites including hydroxyethyl glycine,L-threonine,indoleacrylic acid,β-muricholic acid(β-MCA),cervonoyl ethanolamide(CEA),phosphatidylcholines,and lysophosphatidylcholines.Two metabolites,CEA andβ-MCA,differed significantly in the fibrosis model rats compared to controls(P<0.05)and showed prognostic value for fibrosis.ROC curve analyses performed to calculate the area under the curve(AUC)revealed that CEA andβ-MCA differed significantly in the fibrosis group compared to controls with AUC values exceeding 0.8,and can clearly differentiate early stage from late stage fibrosis or cirrhosis.CONCLUSION This study identified two novel biomarkers of fibrosis,CEA andβ-MCA,which were effective for diagnosing fibrosis in an animal model.

Hypoxia-inducible factor-1α–mediated upregulation of CD99 promotes the proliferation of placental mesenchymal stem cells by regulating ERK1/2

BACKGROUND As human placenta-derived mesenchymal stem cells(hP-MSCs)exist in a physiologically hypoxic microenvironment,various studies have focused on the influence of hypoxia.However,the underlying mechanisms remain to be further explored.AIM The aim was to reveal the possible mechanisms by which hypoxia enhances the proliferation of hP-MSCs.METHODS A hypoxic cell incubator(2.5%O2)was used to mimic a hypoxic microenvironment.Cell counting kit-8 and 5-ethynyl-20-deoxyuridine incorporation assays were used to assay the proliferation of hP-MSCs.The cell cycle was profiled by flow cytometry.Transcriptome profiling of hP-MSCs under hypoxia was performed by RNA sequencing.CD99 mRNA expression was assayed by reverse transcription-polymerase chain reaction.Small interfering RNA-mediated hypoxia-inducible factor 1α(HIF-1α)or CD99 knockdown of hP-MSCs,luciferase reporter assays,and the ERK1/2 signaling inhibitor PD98059 were used in the mechanistic analysis.Protein expression was assayed by western blotting;immunofluorescence assays were conducted to evaluate changes in expression levels.RESULTS Hypoxia enhanced hP-MSC proliferation,increased the expression of cyclin E1,cyclin-dependent kinase 2,and cyclin A2,and decreased the expression of p21.Under hypoxia,CD99 expression was increased by HIF-1α.CD99-specific small interfering RNA or the ERK1/2 signaling inhibitor PD98059 abrogated the hypoxia-induced increase in cell proliferation.CONCLUSION Hypoxia promoted hP-MSCs proliferation in a manner dependent on CD99 regulation of the MAPK/ERK signaling pathway in vitro.

Mesenchymal stem cells from the human umbilical cord ameliorate fulminant hepatic failure and increase survival in mice

BACKGROUND：Cell therapy has been promising for various diseases.We investigated whether transplantation of human umbilical cord mesenchymal stem cells（h UCMSCs）has any therapeutic effects on D-galactosamine/lipopolysaccharide（Gal N/LPS）-induced fulminant hepatic failure in mice.METHODS：h UCMSCs isolated from human umbilical cord were cultured and transplanted via the tail vein into severe combined immune deficiency mice with Gal N/LPS-induced fulminant hepatic failure.After transplantation,the localization and differentiation of h UCMSCs in the injured livers were investigated by immunohistochemical and genetic analy- ses. The recovery of the injured livers was evaluated histologi- cally. The survival rate of experimental animals was analyzed by the Kaplan-Meier method and log-rank test. RESULTS： hUCMSCs expressed high levels of CD29, CD73, CD13, CD105 and CD90, but did not express CD31, CD79b, CD133, CD34, and CD45. Cultured hUCMSCs displayed adip- ogenic and osteogenic differentiation potential. Hematoxylin and eosin staining revealed that transplantation of hUCMSCs reduced hepatic necrosis and promoted liver regeneration. Transplantation of hUCMSCs prolonged the survival rate of mice with fulminant hepatic failure. Polymerase chain reaction for human alu sequences showed the presence of human cells in mouse livers. Positive staining for human albumin, human alpha-fetoprotein and human cytokeratin 18 suggested the for- mation of hUCMSCs-derived hepatocyte-like cells in vivo.CONCLUSIONS： hUCMSC was a potential candidate for stem cell based therapies. After transplantation, hUCMSCs partially repaired hepatic damage induced by GalN/LPS in mice. hUC- MSCs engrafted into the injured liver and differentiated into hepatocyte-like cells.

Long non-coding RNA SNHG16 promotes human placenta-derived mesenchymal stem cell proliferation capacity through the PI3K/AKT pathway under hypoxia

BACKGROUND The effect of hypoxia on mesenchymal stem cells(MSCs)is an emerging topic in MSC biology.Although long non-coding RNAs(lncRNAs)and messenger RNAs(mRNAs)are reported to play a critical role in regulating the biological characteristics of MSCs,their specific expression and co-expression profiles in human placenta-derived MSCs(hP-MSCs)under hypoxia and the underlying mechanisms of lncRNAs in hP-MSC biology are unknown.AIM To reveal the specific expression profiles of lncRNAs in hP-MSCs under hypoxia and initially explored the possible mechanism of lncRNAs on hP-MSC biology.METHODS Here,we used a multigas incubator(92.5%N_(2),5%CO_(2),and 2.5%O_(2))to mimic the potential of hP-MSCs.RNA sequencing technology was applied to identify the exact expression profiles of lncRNAs and mRNAs under hypoxia.RESULTS We identified 289 differentially expressed lncRNAs and 240 differentially expressed mRNAs between the hypoxia and normoxia groups.Among them,the lncRNA SNHG16 was upregulated under hypoxia,which was also validated by reverse transcription-polymerase chain reaction.SNHG16 was confirmed to affect hP-MSC proliferation rates using a SNHG16 knockdown model.SNHG16 overexpression could significantly enhance the proliferation capacity of hP-MSCs,activate the PI3K/AKT pathway,and upregulate the expression of cell cycle-related proteins.CONCLUSION Our results revealed the specific expression characteristics of lncRNAs and mRNAs in hypoxiacultured hP-MSCs and that lncRNA SNHG16 can promote hP-MSC proliferation through the PI3K/AKT pathway.