Therapeutic targets for liver regeneration after acute severe injury: a preclinical overview

G-CSF promotes the viability and angiogenesis of injured liver via direct effects on the liver cells

Background

Presently, liver transplantation is the only treatment strategy for liver failure (LF). Although granulocyte-colony stimulating factor (G-CSF) exhibits protective functions in LF, it is not clear whether it directly affects the liver cells.

Methods and Results

We established an injured liver cell model and observed that G-CSF treatment promoted cell viability and enhanced Ki67 and VEGF-A expression. Thereafter, human umbilical vein endothelial cells (HUVECs) were cultured in a conditioned medium collected from the G-CSF-treated injured liver cells. HUVECs’ proliferation and tubule formation were promoted. Furthermore, in an injured liver mouse model, confirmed via haematoxylin–eosin staining, we evaluated serum alanine aminotransferase activity, Ki67 expression, and microvessel density (MVD). G-CSF treatment significantly relieved liver injury, upregulated Ki67 expression, and enhanced MVD in the injured mouse liver tissue. Additionally, AKT and ERK signal targets were explored, and it was demonstrated that the effects of G-CSF on injured liver cells were mediated through the AKT and ERK signalling pathways.

Conclusions

G-CSF promotes injured liver viability and angiogenesis by directly affecting injured liver cells via the AKT and ERK signalling pathways. These findings improve our understanding of the role of G-CSF in recovery from LF.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-022-07715-4.

Liver ischaemia-reperfusion injury: a new understanding of the role of innate immunity

Liver ischaemia-reperfusion injury (LIRI), a local sterile inflammatory response driven by innate immunity, is one of the primary causes of early organ dysfunction and failure after liver transplantation. Cellular damage resulting from LIRI is an important risk factor not only for graft dysfunction but also for acute and even chronic rejection and exacerbates the shortage of donor organs for life-saving liver transplantation. Hepatocytes, liver sinusoidal endothelial cells and Kupffer cells, along with extrahepatic monocyte-derived macrophages, neutrophils and platelets, are all involved in LIRI. However, the mechanisms underlying the responses of these cells in the acute phase of LIRI and how these responses are orchestrated to control and resolve inflammation and achieve homeostatic tissue repair are not well understood. Technological advances allow the tracking of cells to better appreciate the role of hepatic macrophages and platelets (such as their origin and immunomodulatory and tissue-remodelling functions) and hepatic neutrophils (such as their selective recruitment, anti-inflammatory and tissue-repairing functions, and formation of extracellular traps and reverse migration) in LIRI. In this Review, we summarize the role of macrophages, platelets and neutrophils in LIRI, highlight unanswered questions, and discuss prospects for innovative therapeutic regimens against LIRI in transplant recipients.

A comprehensive investigation on liver regeneration: a meta-analysis and systems biology approach

AIM OF THE STUDY

Liver regeneration is one of the essential fields of regenerative medicine as a branch of tissue engineering and molecular biology that draws global researchers' attention. This study aims to conduct a systematic review and meta-analysis on the high-throughput gene expression microarray dataset of liver regeneration on the NCBI-GEO database to identify the significant genes and signaling pathways and confirm the genes from literature studies on associated diseases.

MATERIAL AND METHODS

We thoroughly searched the NCBI-GEO database to retrieve and screen the GEO microarray datasets' contents. Due to the inclusion of different species in eligible GEO datasets in the meta-analysis, the list of significant genes for the random-effects model were identified. Moreover, we carried out detailed gene analyses for three main gene ontology components and the KEGG signaling pathway. Furthermore, we investigated the possibility of genes' association with liver cancer through the Kaplan-Meier plot.

RESULTS

The random-effects model from six eligible GEO datasets identified 71 genes with eight down-regulated and 63 up-regulated genes. The target genes are involved in various cellular functions such as cell proliferation, cell death, and cell cycle control. Finally, we noted that 58 out of 71 genes are associated with different types of diseases related explicitly to other liver and inflammation diseases.

CONCLUSIONS

The current study assessed various GEO datasets at the early stages of liver regeneration with promising results. The present systematic review and meta-analysis results are beneficial for future novel drug design and discovery specifically for patients in the liver transplantation process.

Periplaneta americana Extracts Accelerate Liver Regeneration via a Complex Network of Pathways

Successful recovery from hepatectomy is partially contingent upon the rate of residual liver regeneration. The traditional Chinese medicines known as Periplaneta americana extracts (PAEs) positively influence wound healing by promoting tissue repair. However, the effect of PAEs on liver regeneration is unknown. We used a mouse liver regeneration model after 70% partial hepatectomy (PH) and a hepatocyte culture to determine whether PAEs can promote liver regeneration as effectively as skin regeneration and establish their modes of action. L02 cells were divided into serum-starved control (NC) and three PAEs (serum starvation + 0.1 mg/ml, 0.5 mg/ml, or 1 mg/ml PAEs) groups. L02 cell proliferation was assessed at 24 h, 48 h, and 72 h by CCK-8 assay. Forty male C57 mice were randomly divided into control (NC), normal saline (NS), PAEs400 (400 mg/kg/d), and PAEs800 (800 mg/kg/d) groups (n = 10 per group). The NS and both PAEs groups were administered normal saline and PAEs, respectively, by gavage for 10 days. Two hours after the tenth gavage, the NS and both PAEs groups were subjected to 70% PH and the residual liver was harvested after 48 h. The hepatic regeneration rate was evaluated and hepatocyte proliferation was estimated by immunohistochemical (IHC) staining for Ki-67. Twelve DEG libraries (three samples per group) were prepared and sequencing was performed in an Illumina HiSeq 2000 (Mus_musculus) at the Beijing Genomics Institute. The genes expressed in the liver tissues and their expression profiles were analyzed by bioinformatics. KEGG was used to annotate, enrich, and analyze the pathways. PAEs promoted hepatocyte proliferation in vitro and in vivo and accelerated mouse liver regeneration after 70% PH. The screening criteria were fold change (FC) ≥ 2 and q-value < 0.001. We identified 1,092 known DEGs in PAEs400 and PAEs800. Of these, 153 were categorized in cellular processes. The KEGG analysis revealed that the aforementioned DEGs participated in several signaling pathways closely associated with cell proliferation including PI3K-Akt, MAPK, Apelin, Wnt, FoxO, mTOR, Ras, VEGF, ErbB, Hippo, and AMPK. It was concluded that PAEs can effectively improve liver regeneration via the synergistic activation of different signaling pathways.