Expression profiles uncover the relationship between erythropoietin and cell proliferation in rat hepatocytes after a partial hepatectomy

An integrated analysis of the circRNA-miRNA-mRNA network reveals novel insights into potential mechanisms of cell proliferation during liver regeneration

Cell proliferation constitutes the fundamental process and driving force behind regrowth during liver regeneration (LR). However, it remains unclear how competing endogenous RNA (ceRNA) networks affect hepatocyte proliferation and liver regeneration. Therefore, this study was designed to explore an LR-specific ceRNA network, which regulates cell proliferation. Based on the microarray data of mRNAs, and high-throughput sequencing data of miRNAs and circRNAs from regenerating livers, this study initially applied known 1484 LR associated mRNAs to perform GO analysis, and then selected 169 LR associated mRNAs involved in cell proliferation and the cell cycle. Subsequently, 188 interactive miRNA-mRNA pairs and 5206 circRNA-miRNA pairs, respectively, were predicted using bioinformatics methods. Next, in view of the differential expressions of these ceRNAs during LR, 26 miRNA-mRNA pairs and 71 circRNA-miRNA pairs were applied to generate a circRNA-miRNA-mRNA regulatory network, and only 14 triple interactive groups were obtained based on the predicted inverse interactions among ceRNAs. Finally, circ_19698/miR-423-5p axis was demonstrated to promote cell proliferation by modulating the expression of MYC, CCNA2, and CCND1 in rat BRL-3A cells. This study suggests a potential regulatory mechanism of cell proliferation in regenerating livers, as well as a novel pathway for modulating ceRNA networks to promote liver regeneration.

Predictive Factors and Microbial Spectrum for Infectious Complications after Hepatectomy with Cholangiojejunostomy in Perihilar Cholangiocarcinoma

Background: Despite advances in surgical techniques and peri-operative management, post-operative infectious complications still are common after perihilar cholangiocarcinoma (PHCC). This study investigated the predictive factors and microbial spectrum for infections after hepatectomy with cholangiojejunostomy performed to treat PHCC. Methods: A total of 70 consecutive patients, who underwent hepatectomy with cholangiojejunostomy by the same surgeons at a tertiary referral medical center between September 2010 and January 2019, were enrolled. Clinical data were reviewed for multivariable analysis to find independent risk factors for infectious complications. Microorganisms isolated from bile and infection sites were counted to explore the microbial spectrum. Results: A total of 43 patients (61.4%) suffered post-operative infections (33 with surgical site infection [SSI], four with bacteremia, three with pneumonia, 10 with cholangitis, and two with fungus infectious stomatitis), and 28 of them (65.1%) had a positive bile culture. Four independent risk factors were identified: male sex (odds ratio [OR] 12.737; 95% confidence interval [CI] 2.298-70.611; p = 0.004), red blood cell (RBC) count <3.8 × 10¹²/L (OR 5.085; 95% CI 1.279-20.211; p = 0.021), total cholesterol (TC) <2.90 mmol/L (OR 5.715; 95% CI 1.534-21.299; p = 0.009), and serum Na⁺ >145 mmol/L (OR 10.387; 95% CI 1.559-69.201; p = 0.016) on post-operative day (POD) 1. A total of 217 and 196 microorganisms were cultured from 311 and 627 specimens, respectively, collected from pre-/intra-operative bile and possible infection sites. Staphylococcus, Enterococcus, Acinetobacter, Streptococcus, and Escherichia were the most common findings of bile culture. The first five organisms most frequently isolated from infection sites were Enterococcus, Staphylococcus, Klebsiella, Acinetobacter, and Candida. A total of 18 patients (64.3%) had at least one species isolated from infection sites that had appeared in a previous bile culture. Conclusions: Male sex, erythrocytopenia, hypocholesterolemia, and hypernatremia on POD 1 are independent risk factors for infectious complications. For patients without positive bile cultures, third-generation cephalosporins could be considered as the prophylactic antibiotic. It is important to monitor the pathogens throughout the hospital stay.

Mechanical Stretch Promotes the Osteogenic Differentiation of Bone Mesenchymal Stem Cells Induced by Erythropoietin

INTRODUCTION

The effects of erythropoietin (EPO) on the behaviors of bone marrow mesenchymal stem cells (BMSCs) subjected to mechanical stretch remain unclear. This study was therefore aimed at establishing the dose-response effect of EPO stimulation on rat BMSCs and investigating the effects of mechanical stretch combined with EPO on the proliferation and osteogenic differentiation of BMSCs.

MATERIAL AND METHODS

The proliferation and osteogenic differentiation of rat BMSCs were examined and compared using EPO with different concentrations. Thereafter, BMSCs were subjected to 10% elongation using a Flexcell strain unit, combined with 20 IU/ml EPO. The proliferation of BMSCs was detected by Cell Counting Kit-8, colony formation assay, and cell cycle assay; meanwhile, the mRNA expression levels of Ets-1, C-myc, Ccnd1, and C-fos were detected by reverse transcription and real-time quantitative PCR (qPCR). The osteogenic differentiation of BMSCs was detected by alkaline phosphatase (ALP) staining, and the mRNA expression levels of ALP, OCN, COL, and Runx2 were detected by qPCR. The role of the extracellular signal-regulated kinases 1/2 (ERK1/2) in the osteogenesis of BMSCs stimulated by mechanical stretch combined with 20 IU/ml EPO was examined by Western blot.

RESULTS

Our results showed that effects of EPO on BMSCs included a dose-response relationship, with the 20 IU/ml EPO yielding the largest. Mechanical stretch combined with 20 IU/ml EPO promoted proliferation and osteogenic differentiation of BMSCs. The increase in ALP, mineral deposition, and osteoblastic genes induced by the mechanical stretch-EPO combination was inhibited by U0126, an ERK1/2 inhibitor.

CONCLUSION

EPO was able to promote the proliferation and osteogenic differentiation of BMSCs, and these effects were enhanced when combined with mechanical stretch. The underlying mechanism may be related to the activation of the ERK1/2 signaling pathway.