Knockdown of augmenter of liver regeneration in HK-2 cells inhibits inflammation response via the mitogen-activated protein kinase signaling pathway

Targeted editing of CCL5 with CRISPR-Cas9 nanoparticles enhances breast cancer immunotherapy

Breast cancer remains one of the leading causes of cancer-related mortality among women worldwide. Immunotherapy, a promising therapeutic approach, often faces challenges due to the immunosuppressive tumor microenvironment. This study explores the innovative use of CRISPR-Cas9 technology in conjunction with FCPCV nanoparticles to target and edit the C-C Motif Chemokine Ligand 5 (CCL5) gene, aiming to improve the efficacy of breast cancer immunotherapy. Single-cell RNA sequencing (scRNA-seq) and TCGA-BRCA data identified CCL5 as a key immune-related gene in breast cancer. Using CRISPR-Cas9, sgRNA targeting CCL5 was designed and delivered to breast cancer cells and humanized mouse models via FCPCV nanoparticles. In vitro experiments demonstrated that FCPCV nanoparticles effectively silenced CCL5, enhanced CD8+ T cell activity, and increased the production of cytokines such as IFN-γ, TNF-α, and GZMB. In vivo studies revealed significant tumor suppression, improved immune microenvironment, and increased CD8+/CD4+ ratios in treated mice, without notable toxic side effects. These findings highlight the potential of CRISPR-Cas9 nanoparticle-mediated gene editing as a novel strategy for enhancing breast cancer immunotherapy, providing a new direction for personalized and effective cancer treatment.

Enhancing cardiac repair post-myocardial infarction: a study on GATM/Gel hydrogel therapeutics

BACKGROUND AND PURPOSE

Significant advancements in therapeutic approaches are imperative to address the prevalent impact of myocardial infarction (MI) on morbidity and mortality rates worldwide. This study explores the therapeutic potential of GATM/Gel hydrogel, focusing on its ability to enhance cardiac repair and functionality after MI through modulation of inflammatory and repair pathways.

EXPERIMENTAL APPROACH

The effects of GATM/Gel hydrogel on cardiac recovery were studied in a murine MI model. HA-CHO and gelatin solutions were mixed in situ using a dual syringe with a static mixing needle, and the resulting hydrogel was applied directly to the epicardium during MI modeling, followed by repositioning of the heart and closure of the thorax. Comprehensive in vivo assessments-including echocardiography, electrocardiography, and histopathological analysis-were combined with molecular techniques such as RT-qPCR, Western blotting, and immunofluorescence to elucidate the underlying mechanisms. Key cellular and molecular changes were tracked, focusing on macrophage polarization, angiogenesis, and modulation of the TNF/TNFR2 signaling pathway.

KEY RESULTS

Employing the GATM/Gel hydrogel led to a substantial improvement in heart function, shown through enhanced ejection fraction and fractional shortening, and reduced infarction size compared to control groups. Mechanistically, the hydrogel promoted the polarization of anti-inflammatory M2 macrophages and stimulated angiogenesis. Moreover, treatment with GATM/Gel hydrogel altered the TNF/TNFR2 pathway, pivotal in mediating inflammatory responses and facilitating myocardial repair. The discoveries highlight the possibility of GATM/Gel hydrogels as an innovative remedy for MI, providing a twofold role in regulating inflammation and fostering recovery.

Novel anti-inflammatory properties of mannose oligosaccharides in the treatment of inflammatory bowel disease via LGALS3 modulation

This study investigates the role of Gum Arabic Mannose Oligosaccharides (GA-MOS) in modulating gut microbiota and alleviating symptoms of Inflammatory Bowel Disease (IBD). Employing both in vitro and in vivo models, we explored how GA-MOS influences microbial communities, particularly focusing on their capacity to enhance health-associated bacteria and reduce pathogenic species within the gut environment. Our findings reveal that GA-MOS treatment significantly altered the gut microbiota composition, increasing the abundance of anti-inflammatory bacteria while decreasing pro-inflammatory species, thus contributing to a reduction in gut inflammation and an improvement in intestinal barrier function. Detailed molecular analyses further demonstrated that these changes in microbiota were associated with modifications in the host's immune response, particularly through the suppression of key inflammatory pathways and cytokines involved in IBD progression. These results underscore the potential of dietary polysaccharides like GA-MOS as therapeutic agents in managing dysbiosis and inflammatory conditions in the gut, offering a promising approach for enhancing microbial health and overall disease management in IBD. This study provides novel insights into the bioactive properties of MOS and their interactions with gut microbiota, suggesting broader implications for their use in microbiome-centered therapies.

Enhancing Fracture Healing with 3D Bioprinted Hif1a-Overexpressing BMSCs Hydrogel: A Novel Approach to Accelerated Bone Repair

Addressing the urgent need for effective fracture treatments, this study investigates the efficacy of a 3D bioprinted biomimetic hydrogel, enriched with bone marrow mesenchymal stem cells (BMSCs) and targeted hypoxia-inducible factor 1 alpha (Hif1a) gene activation, in enhancing fracture healing. A photocross-linkable bioink, gelatin methacryloyl bone matrix anhydride (GBMA) is developed, and selected its 5% concentration for bioink formulation. Rat BMSCs are isolated and combined with GBMA to create the GBMA@BMSCs bioink. This bioink is then used in 3D bioprinting to fabricate a hydrogel for application in a rat femoral fracture model. Through transcriptome sequencing, WGCNA, and Venn analysis, the hypoxia-inducible factor Hif1a is identified as a critical gene in the fracture healing process. In vitro studies showed that Hif1a promoted BMSC proliferation, chondrogenic differentiation, and cartilage matrix stability. The in vivo application of the GBMA@BMSCs hydrogel with Hif1a overexpression significantly accelerated fracture healing, evidenced by early and enhanced cartilage callus formation. The study demonstrates that 3D bioprinting of GBMA@BMSCs hydrogel, particularly with Hif1a-enhanced BMSCs, offers a promising approach for rapid and effective fracture repair.

Novel insights into the heterogeneity of FOXP3 + Treg cells in drug-induced allergic reactions through single-cell transcriptomics

This study uncovers the novel heterogeneity of FOXP3 + regulatory T (Treg) cells and their pivotal role in modulating immune responses during drug-induced allergic reactions, employing cutting-edge single-cell transcriptomics. We established a mouse model for drug-induced allergic reactions and utilized single-cell RNA sequencing (scRNA-seq) to analyze the transcriptomic landscapes of FOXP3 + Treg cells isolated from affected tissues. The study involved both in vitro and in vivo approaches to evaluate the impact of FOXP3 expression levels on the immunoregulatory functions of Treg cells during allergic responses. Techniques included flow cytometry, cluster analysis, principal component analysis (PCA), CCK8 and CSFE assays for cell proliferation, LDH release assays for toxicity, ELISA for cytokine profiling, and CRISPR/Cas9 technology for gene editing. Our findings revealed significant transcriptomic heterogeneity among FOXP3 + Treg cells in the context of drug-induced allergic reactions, with distinct subpopulations exhibiting unique gene expression profiles. This heterogeneity suggests specialized roles in immune regulation. We observed a decrease in the proliferative capacity and cytokine secretion of FOXP3 + Treg cells following allergic stimulation, alongside an increase in reaction toxicity. Manipulating FOXP3 expression levels directly influenced these outcomes, where FOXP3 deletion exacerbated allergic responses, whereas its overexpression mitigated them. Notably, in vivo experiments demonstrated that FOXP3 overexpression significantly reduced the severity of allergic skin reactions in mice. Our study presents novel insights into the heterogeneity and crucial immunoregulatory role of FOXP3 + Treg cells during drug-induced allergic reactions. Overexpression of FOXP3 emerges as a potential therapeutic strategy to alleviate such allergic responses. These findings contribute significantly to our understanding of immune regulation and the development of targeted treatments for drug-induced allergies.

HIF-1α Pathway Orchestration by LCN2: A Key Player in Hypoxia-Mediated Colitis Exacerbation

In this study, we investigated the role of hypoxia in the development of chronic inflammatory bowel disease (IBD), focusing on its impact on the HIF-1α signaling pathway through the upregulation of lipocalin 2 (LCN2). Using a murine model of colitis induced by sodium dextran sulfate (DSS) under hypoxic conditions, transcriptome sequencing revealed LCN2 as a key gene involved in hypoxia-mediated exacerbation of colitis. Bioinformatics analysis highlighted the involvement of crucial pathways, including HIF-1α and glycolysis, in the inflammatory process. Immune infiltration analysis demonstrated the polarization of M1 macrophages in response to hypoxic stimulation. In vitro studies using RAW264.7 cells further elucidated the exacerbation of inflammation and its impact on M1 macrophage polarization under hypoxic conditions. LCN2 knockout cells reversed hypoxia-induced inflammatory responses, and the HIF-1α pathway activator dimethyloxaloylglycine (DMOG) confirmed LCN2's role in mediating inflammation via the HIF-1α-induced glycolysis pathway. In a DSS-induced colitis mouse model, oral administration of LCN2-silencing lentivirus and DMOG under hypoxic conditions validated the exacerbation of colitis. Evaluation of colonic tissues revealed altered macrophage polarization, increased levels of inflammatory factors, and activation of the HIF-1α and glycolysis pathways. In conclusion, our findings suggest that hypoxia exacerbates colitis by modulating the HIF-1α pathway through LCN2, influencing M1 macrophage polarization in glycolysis. This study contributes to a better understanding of the mechanisms underlying IBD, providing potential therapeutic targets for intervention.

New mechanistic understanding of osteoclast differentiation and bone resorption mediated by P2X7 receptors and PI3K-Akt-GSK3β signaling

OBJECTIVE

Osteoporosis is a global health issue characterized by decreased bone mass and microstructural degradation, leading to an increased risk of fractures. This study aims to explore the molecular mechanism by which P2X7 receptors influence osteoclast formation and bone resorption through the PI3K-Akt-GSK3β signaling pathway.

METHODS

An osteoporosis mouse model was generated through ovariectomy (OVX) in normal C57BL/6 and P2X7f/f; LysM-cre mice. Osteoclasts were isolated for transcriptomic analysis, and differentially expressed genes were selected for functional enrichment analysis. Metabolite analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and multivariate statistical analysis and pattern recognition were used to identify differential lipid metabolism markers and their distribution. Bioinformatics analyses were conducted using the Encyclopedia of Genes and Genomes database and the MetaboAnalyst database to assess potential biomarkers and create a metabolic pathway map. Osteoclast precursor cells were used for in vitro cell experiments, evaluating cell viability and proliferation using the Cell Counting Kit 8 (CCK-8) assay. Osteoclast precursor cells were induced to differentiate into osteoclasts using macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-beta ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) staining was performed to compare differentiation morphology, size, and quantity between different groups. Western blot analysis was used to assess the expression of differentiation markers, fusion gene markers, and bone resorption ability markers in osteoclasts. Immunofluorescence staining was employed to examine the spatial distribution and quantity of osteoclast cell skeletons, P2X7 protein, and cell nuclei, while pit assay was used to evaluate osteoclast bone resorption ability. Finally, in vivo animal experiments, including micro computed tomography (micro-CT), hematoxylin and eosin (HE) staining, TRAP staining, and immunohistochemistry, were conducted to observe bone tissue morphology, osteoclast differentiation, and the phosphorylation level of the PI3K-Akt-GSK3β signaling pathway.

RESULTS

Transcriptomic and metabolomic data collectively reveal that the P2X7 receptor can impact the pathogenesis of osteoporosis through the PI3K-Akt-GSK3β signaling pathway. Subsequent in vitro experiments showed that cells in the Sh-P2X7 + Recilisib group exhibited increased proliferative activity (1.15 versus 0.59), higher absorbance levels (0.68 versus 0.34), and a significant increase in resorption pit area (13.94 versus 3.50). Expression levels of osteoclast differentiation-related proteins MMP-9, CK, and NFATc1 were markedly elevated (MMP-9: 1.72 versus 0.96; CK: 2.54 versus 0.95; NFATc1: 3.05 versus 0.95), along with increased fluorescent intensity of F-actin rings. In contrast, the OE-P2X7 + LY294002 group showed decreased proliferative activity (0.64 versus 1.29), reduced absorbance (0.34 versus 0.82), and a significant decrease in resorption pit area (5.01 versus 14.96), accompanied by weakened expression of MMP-9, CK, and NFATc1 (MMP-9: 1.14 versus 1.79; CK: 1.26 versus 2.75; NFATc1: 1.17 versus 2.90) and decreased F-actin fluorescent intensity. Furthermore, in vivo animal experiments demonstrated that compared with the wild type (WT) + Sham group, mice in the WT + OVX group exhibited significantly increased levels of CTX and NTX in serum (CTX: 587.17 versus 129.33; NTX: 386.00 versus 98.83), a notable decrease in calcium deposition (19.67 versus 53.83), significant reduction in bone density, increased trabecular separation, and lowered bone mineral density (BMD). When compared with the KO + OVX group, mice in the KO + OVX + recilisib group showed a substantial increase in CTX and NTX levels in serum (CTX: 503.50 versus 209.83; NTX: 339.83 versus 127.00), further reduction in calcium deposition (29.67 versus 45.33), as well as decreased bone density, increased trabecular separation, and reduced BMD.

CONCLUSION

P2X7 receptors positively regulate osteoclast formation and bone resorption by activating the PI3K-Akt-GSK3β signaling pathway.

Delivery of miR-15b-5p via magnetic nanoparticle-enhanced bone marrow mesenchymal stem cell-derived extracellular vesicles mitigates diabetic osteoporosis by targeting GFAP

Diabetic osteoporosis (DO) presents significant clinical challenges. This study aimed to investigate the potential of magnetic nanoparticle-enhanced extracellular vesicles (GMNPE-EVs) derived from bone marrow mesenchymal stem cells (BMSCs) to deliver miR-15b-5p, thereby targeting and downregulating glial fibrillary acidic protein (GFAP) expression in rat DO models. Data was sourced from DO-related RNA-seq datasets combined with GEO and GeneCards databases. Rat primary BMSCs, bone marrow-derived macrophages (BMMs), and osteoclasts were isolated and cultured. EVs were separated, and GMNPE targeting EVs were synthesized. Bioinformatic analysis revealed a high GFAP expression in DO-related RNA-seq and GSE26168 datasets for disease models. Experimental results confirmed elevated GFAP in rat DO bone tissues, promoting osteoclast differentiation. miR-15b-5p was identified as a GFAP inhibitor, but was significantly downregulated in DO and enriched in BMSC-derived EVs. In vitro experiments showed that GMNPE-EVs could transfer miR-15b-5p to osteoclasts, downregulating GFAP and inhibiting osteoclast differentiation. In vivo tests confirmed the therapeutic potential of this approach in alleviating rat DO. Collectively, GMNPE-EVs can effectively deliver miR-15b-5p to osteoclasts, downregulating GFAP expression, and hence, offering a therapeutic strategy for rat DO.

MAPKAP1 orchestrates macrophage polarization and lipid metabolism in fatty liver-enhanced colorectal cancer

Various factors, including fatty liver and macrophage alterations, influence colorectal cancer (CRC). This study explores the mechanistic role of fatty liver in CRC progression, focusing on macrophage polarization and lipid metabolism. A murine fatty liver model was created with a high-fat diet (HFD), and CRC was induced using AOM and DSS. Single-cell transcriptome sequencing (scRNA-seq) identified MAPKAP1 as a critical gene promoting CRC via M2 macrophage polarization and lipid metabolism reprogramming. Prognosis analysis on the TCGA-CRC dataset confirmed MAPKAP1's significance. In vitro and in vivo experiments demonstrated that EVs from fatty liver cells enhanced MAPKAP1 expression, accelerating CRC development and metastasis. HFD exacerbated CRC, but fatty acid inhibitors delayed progression. Fatty liver upregulates MAPKAP1, driving M2 macrophage polarization and lipid metabolism changes, worsening CRC. These findings suggest potential therapeutic strategies for CRC, particularly targeting lipid metabolism and macrophage-mediated tumor promotion.

Molecular mechanism of NR4A1/MDM2/P53 signaling pathway regulation inducing ferroptosis in renal tubular epithelial cells involved in the progression of renal ischemia-reperfusion injury

Revealing the possible molecular mechanism of the NR4A1 (nuclear receptor subfamily 4 group A member 1)-MDM2 (MDM2 proto-oncogene)-P53 (tumor protein p53) signaling pathway that induces ferroptosis in renal tubular epithelial cells. Renal ischemia-reperfusion injury (RIRI) -related datasets were obtained from the GEO database. Differentially expressed genes in RIRI were analyzed using R language, intersected with RIRI-related genes in the GeneCard database, and retrieved from the literature to finally obtain differential ferroptosis-related genes. An in vitro cell model of RIRI was constructed using mouse renal cortical proximal tubule epithelial cells (mRTEC cells) treated with hypoxia-reoxygenation (H/R). Bioinformatic analysis showed that NR4A1 may be involved in RIRI through the induction of ferroptosis; in addition, we predicted through online databases that the downstream target gene of NR4A1, MDM2, could be targeted and regulated by ChIP and dual luciferase assays, and that NR4A1 could prevent MDM2 by inhibiting it, and NR4A1 was able to promote ferroptosis by inhibiting the ubiquitinated degradation of P53. NR4A1 expression was significantly increased in mRTEC cells in the hypoxia/reoxygenation model, and the expression of ferroptosis-related genes was increased in vitro experiments. NR4A1 reduces the ubiquitinated degradation of P53 by targeting the inhibition of MDM2 expression, thereby inducing ferroptosis and ultimately exacerbating RIRI by affecting the oxidative respiration process in mitochondria and producing oxidized lipids. This study presents a novel therapeutic approach for the clinical treatment of renal ischemia-reperfusion injury by developing drugs that inhibit NR4A1 to alleviate kidney damage caused by renal ischemia-reperfusion.

Molecular mechanisms of AMPK/YAP/NLRP3 signaling pathway affecting the occurrence and development of ankylosing spondylitis

BACKGROUND

Investigate the AMPK (protein kinase AMP-activated catalytic subunit alpha 1)/YAP (Yes1 associated transcriptional regulator)/NLRP3 (NLR family pyrin domain containing 3) signaling pathway's role in ankylosing spondylitis (AS) development using public database analysis, in vitro and in vivo experiments.

METHODS

Retrieve AS dataset, analyze differential gene expression in R, conduct functional enrichment analysis, collect 30 AS patient and 30 normal control samples, and construct a mouse model. ELISA, IP, and knockdown experiments were performed to detect expression changes.

RESULTS

NLRP3 was identified as a significant AS-related gene. Caspase-1, IL-1β, IL-17A, IL-18, IL-23, YAP, and NLRP3 were upregulated in AS patients. Overexpressing AMPK inhibited YAP's blockade on NLRP3 ubiquitination, reducing ossification in fibroblasts. Inhibiting AMPK exacerbated AS symptoms in AS mice.

CONCLUSION

AMPK may suppress YAP expression, leading to NLRP3 inflammasome inhibition and AS alleviation.

Possible role of nuclear factor erythroid 2-related factor 2 in the progression of human colon precancerous lesions

BACKGROUND

Increased levels of oxidative stress/cell inflammation contribute to colorectal cancer (CRC) onset. Nuclear factor-erythroid 2-related factor 2 (Nrf2) and its controlled growth factor erv1-like (Gfer) gene regulate redox-sensitive and anti-inflammatory mechanisms, respectively, which can contribute to promoting cancer development.

AIM

We evaluated Nrf2 and Gfer RNA expression and Nrf2 protein expression in colon mucosa in order to establish their possible involvement in the early stage of CRC.

METHODS

Forty subjects were enrolled after a histological evaluation of their colon biopsies. They included 20 subjects with a sporadic colorectal adenoma (SpCA group) and 20 without precancerous lesions (controls). Biopsy samples were processed for gene expression analysis and protein expression, using Real-time PCR and immunofluorescence confocal microscopy, respectively.

RESULTS

Nrf2 and Gfer mRNA expression were significantly reduced (p=0.007 and p<0.003, respectively) in SpCA tissues compared to normal mucosa from controls. Furthermore, immunofluorescence analysis confirmed a relevant reduction of Nrf2 in SpCA tissue compared to normal tissue from controls.

CONCLUSIONS

Our data confirm the hypothesis that Nrf2 and Gfer expression may be involved in the initial hits contributing to the multistep process of colon carcinogenesis. Further larger studies are needed to confirm if Nrf2 and Gfer are potential risk/prognostic factors for cancer development.

Augmenter of Liver Regeneration (ALR) Protects Kidney from Ischemia/Reperfusion (I/R) Injury via Regulation of TLR4/MAPK Signaling Pathway

Toll-like receptor 4 (TLR4) can mediate innate activation and inflammation, and it is typically expressed within the ischemic kidney. Augmenter of liver regeneration (ALR) acts as an immunoregulator with a high expression in the kidney induced by renal ischemia/reperfusion (I/R) injury. Exogenous ALR has indicated a role in protecting the kidney from I/R injury. The protective effect of ALR is due to the immune regulatory function which remains to be elucidated. In this study, rats induced by renal I/R were treated with recombinant human ALR (rhALR) and demonstrated that the animals were protected from kidney I/R injury, implying that the rhALR-treated rats had less tubular damage than those untreated rats. Meanwhile, tubular epithelial cell apoptosis, neutrophil (24 h) and macrophage (72 h) infiltration to tubulointerstitium, and levels of inflammatory cytokines were decreased considerably in the rhALR-treated rats as compared to control. Additionally, rhALR could downregulate mRNA expression of TLR4 endogenous ligands and restrain its activation in renal I/R injury rats. It has also been proved that anti-rhALR antibody blocked the inhibition of rhALR of the immune inflammatory response in hypoxia/reoxygenation (H/R) injury in vitro. In rhALR+anti-rhALR antibody-intervened H/R cells, the expression of inflammatory cytokines was upregulated compared with the rhALR-treated cells. Taken together, rhALR could regulate the TLR4 signaling pathway to relieve inflammatory response, thereby protecting renal I/R injury, indicating that ALR is likely to be introduced to develop novel immune therapies for renal I/R injury.

Propofol Attenuates Hypoxia/Reoxygenation-Induced Apoptosis and Autophagy in HK-2 Cells by Inhibiting JNK Activation

PURPOSE

The aim of this study was to investigate whether propofol could attenuate hypoxia/reoxygenation-induced apoptosis and autophagy in human renal proximal tubular cells (HK-2) by inhibiting JNK activation.

MATERIALS AND METHODS

HK-2 cells were treated with or without propofol or JNK inhibitor SP600125 for 1 hour and then subjected to 15 hours of hypoxia and 2 hours of reoxygenation (H/R). Cell viability and LDH release were measured with commercial kits. Cell apoptosis was evaluated by flow cytometry. The expressions of p-JNK, cleaved-caspase-3, Bcl-2, and autophagy markers LC3 and p62 were measured by Western blot or immunofluorescence.

RESULTS

HK-2 cells exposed to H/R insult showed higher cell injury (detected by increased LDH release and decreased cell viability), increased cell apoptosis index and expression of cleaved-caspase-3, a decrease in the expression of Bcl-2 accompanied by increased expression of p-JNK and LC3II, and a decrease in expression of p62. All of these alterations were attenuated by propofol treatment. Similar effects were provoked upon treatment with the JNK inhibitor SP600125. Moreover, the protective effects were more obvious with the combination of propofol and SP600125.

CONCLUSION

These results suggest that propofol could attenuate hypoxia/reoxygenation induced apoptosis and autophagy in HK-2 cells, probably through inhibiting JNK activation.

Augmenter of liver regeneration: Essential for growth and beyond

Liver regeneration is a well-orchestrated process that is triggered by tissue loss due to trauma or surgical resection and by hepatocellular death induced by toxins or viral infections. Due to the central role of the liver for body homeostasis, intensive research was conducted to identify factors that might contribute to hepatic growth and regeneration. Using a model of partial hepatectomy several factors including cytokines and growth factors that regulate this process were discovered. Among them, a protein was identified to specifically support liver regeneration and therefore was named ALR (Augmenter of Liver Regeneration). ALR protein is encoded by GFER (growth factor erv1-like) gene and can be regulated by various stimuli. ALR is expressed in different tissues in three isoforms which are associated with multiple functions: The long forms of ALR were found in the inner-mitochondrial space (IMS) and the cytosol. Mitochondrial ALR (23 kDa) was shown to cooperate with Mia40 to insure adequate protein folding during import into IMS. On the other hand short form ALR, located mainly in the cytosol, was attributed with anti-apoptotic and anti-oxidative properties as well as its inflammation and metabolism modulating effects. Although a considerable amount of work has been devoted to summarizing the knowledge on ALR, an investigation of ALR expression in different organs (location, subcellular localization) as well as delineation between the isoforms and function of ALR is still missing. This review provides a comprehensive evaluation of ALR structure and expression of different ALR isoforms. Furthermore, we highlight the functional role of endogenously expressed and exogenously applied ALR, as well as an analysis of the clinical importance of ALR, with emphasis on liver disease and in vivo models, as well as the consequences of mutations in the GFER gene.

Progress in research of augmenter of liver regeneration

Augmenter of liver regeneration (ALR), also known as hepatic stimulatory substance or hepatopoietin, is expressed ubiquitously in all organs, and exclusively in hepatocytes in the liver. Over the past decade, research indicates that ALR is able to promote growth of hepatocytes in the regenerating or injured liver, and plays an important role in hepatocyte transplantation, the pathogenesis of fulminant hepatitis, liver regeneration, and the development of hepatocellular carcinoma.

Decreased expression of the augmenter of liver regeneration results in growth inhibition and increased chemosensitivity of acute T lymphoblastic leukemia cells

Augmenter of liver regeneration (ALR) plays crucial roles in cell survival and growth. Previous studies have demonstrated that ALR exerts a protective effect on toxic agent‑induced cell death in acute T lymphoblastic leukemia cells and ALR knockdown can sensitize cancer cells to radiation. However, the biological functions of ALR against drug resistance in T-cell acute lymphoblastic leukemia are mostly unknown. In the present study, we investigated the effect of small interfering RNA (siRNA)-induced ALR silencing on cell proliferation and sensitivity to vincristine (VCR) of Jurkat cells. We found that ALR siRNA effectively decreased the ALR expression, then inhibited cell growth and increased sensitivity to VCR in Jurkat cells. Flow cytometry assay revealed that the downregulation of ALR expression promoted cell apoptosis and regulated cell cycle distribution. Following incubation with VCR, apoptosis-related proteins, such as pro-PARP, pro-caspase 8, pro-caspase 3 and Bcl-2 were downregulated in the siRNA/ALR group. Pretreatment with siRNA/ALR in combination with VCR resulted in prolonged G2/M arrest, accompanied by downregulation of cdc25c and cdc2 expression and dissociation of cyclin B1. In conclusion, the results of this study demonstrated that targeted inhibition of the ALR expression in Jurkat cells triggered cell growth inhibition and sensitized cells to VCR via promoting apoptosis and regulating the cell cycle.

Augmenter of liver regeneration protects against carbon tetrachloride-induced liver injury by promoting autophagy in mice

BACKGROUND

Augmenter of liver regeneration (ALR) exerts strong hepatoprotective properties in various animal models of liver injury, but its protective mechanisms have not yet been explored. Autophagy is a recently recognized rudimentary cellular response to inflammation and injury. The aim of this study was to test the hypothesis that ALR may protect against acute liver injury through the autophagic pathway.

METHODS

The level and role of ALR in liver injury were studied in a mouse model of acute liver injury induced by carbon tetrachloride (CCl4). The effect of ALR on autophagy was analyzed in vitro and in vivo. After autophagy was inhibited by 3-methyladenine (3-MA), apoptosis and proliferation were detected in the mouse model with acute liver injury. The ALR and autophagic levels were measured in patients with liver cirrhosis (LC) and acute liver failure (ALF), respectively.

RESULTS

During the progression of acute liver injury, the ALR levels increased slightly in early stage and significantly decreased in late stage in mice. Treatment with an ALR plasmid via tail vein injection protected mice against acute liver injury. The protective effect of ALR relied on the induction of autophagy, which was supported by the following evidence: (1) ALR overexpression directly induced autophagy flux in vitro and in vivo; and (2) ALR treatment suppressed apoptosis and promoted proliferation in mice exposed to CCl4, but the inhibition of autophagy reversed these effects. More importantly, the ALR levels decreased in patients with LC and ALF compared with normal controls.

CONCLUSION

We demonstrated that ALR ameliorated liver injury via an autophagic mechanism, which indicates a potential therapeutic application for liver injury.

A preliminary in vivo study of the effects of OPN on rat liver regeneration induced by partial hepatectomy

Osteopontin (OPN) is a member of Th1 cytokine secreted by activated lymphocytes and macrophages. However, it deserves to be studied whether OPN could promote cell activation or proliferation, and then facilitate hepatic self-repair during liver regeneration (LR). This study is designed to further reveal the effects of OPN on LR in vivo. Firstly, quantitative reverse transcription-PCR (qRT-PCR) and western blot (WB) were utilized to validate the expression profile of endogenous OPN in rat regenerating livers after partial hepatectomy (PH). Then OPN expression vector, two shRNA expression vectors and their respective test vectors were successfully constructed. Afterwards, test vectors were administrated into mouse livers via tail vein to find the more efficient shRNA. Furthermore, OPN expression vector and the more efficient shRNA expression vector were injected into rat regenerating livers, and then the changes in liver regeneration and hepatic microstructure were respectively detected by liver regeneration rate and HE staining, while the expressions of several marker genes were detected by qRT-PCR and WB. Endogenous OPN was strikingly up-regulated in both mRNA and protein level during LR, especially at 12 and 72 h after PH. The shRNA expression vector Opn(313) was found to be more efficient than Opn(887) in silencing the expression of Opn. Then OPN expression vector and Opn(313) were injected into rat remnant livers, and it showed that OPN overexpression aggravated hepatic necrosis and leukocytes infiltration, while OPN silencing inhibited liver regeneration rate and the expressions of PCNA and CCL2, but augmented that of BAX. In conclusion, OPN might enhance inflammation and cell proliferation, attenuate cell apoptosis, and ultimately facilitate liver regeneration at the termination stage of liver regeneration.

Lipid deposition in liver cells: The influence of short form augmenter of liver regeneration

BACKGROUND AND OBJECTIVE

The short form augmenter of liver regeneration (sfALR) is a novel human hepatotrophic growth factor. The aim of this study was to investigate the potential role of sfALR in NAFLD.

METHODS

The free fatty acids (FFA) induced lipid accumulation in mouse liver parenchymal cells was examined by Oil Red O staining and triglyceride level determination. The cell cycle was determined by flow cytometry and the proliferation was assessed by CCK8. The expression levels of gfer, miR-122, srebp-1c, fas, dgat2, acc1 and Lrp1B were assessed by quantitative real-time PCR. Furthermore, the MAPK pathway was detected by western blot.

RESULTS

The results showed that sfALR could alleviate the lipid accumulation in mice both in vivo and in vitro. sfALR relieved the proliferation inhibition and G2 arrest of mouse liver parenchymal cells induced by FFAs. Free fatty acids affected gfer expression in a time-and dose-dependent way. And sfALR suppressed JNK activation, increased miR-122 level and reduced fatty acid synthesis-related gene expression.

CONCLUSION

These findings suggested that sfALR could alleviate the severity of fatty liver in mice.

Magnesium isoglycyrrhizinate inhibits inflammatory response through STAT3 pathway to protect remnant liver function

AIM: To investigate the protective effect of magnesium isoglycyrrhizinate (MgIG) on excessive hepatectomy animal model and its possible mechanism.

METHODS: We used the standard 90% hepatectomy model in Sprague-Dawley rats developed using the modified Emond’s method, in which the left, middle, right upper, and right lower lobes of the liver were removed. Rats with 90% liver resection were divided into three groups, and were injected intraperitoneally with 3 mL saline (control group), 30 mg/kg (low-dose group) and 60 mg/kg (high-dose group) of MgIG, respectively. Animals were sacrificed at various time points and blood was drawn from the vena cava. Biochemical tests were performed with an automatic biochemical analyzer for the following items: serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamyl endopeptidase, total bilirubin (TBil), direct bilirubin (DBil), total protein, albumin, blood glucose (Glu), hyper-sensitivity C-reactive protein, prothrombin time (PT), and thrombin time (TT). Postoperative survival time was observed hourly until death. Hepatocyte regeneration was analyzed by immunohistochemistry. Serum inflammatory cytokines (IL-1, IL-6, IL-10, and iNOS) was analyzed by ELISA. STAT3 protein and mRNA were analyzed by Western blot and quantitative reverse-transcription PCR, respectively.

RESULTS: The high-dose group demonstrated a significantly prolonged survival time, compared with both the control and the low-dose groups (22.0 ± 4.7 h vs 8.9 ± 2.0 vs 10.3 ± 3.3 h, P = 0.018). There were significant differences among the groups in ALT, Glu and PT levels starting from 6 h after surgery. The ALT levels were significantly lower in the MgIG treated groups than in the control group. Both Glu and PT levels were significantly higher in the MgIG treated groups than in the control group. At 12 h, ALT, AST, TBil, DBil and TT levels showed significant differences between the MgIG treated groups and the control group. No significant differences in hepatocyte regeneration were found. Compared to the control group, the high-dose group showed a significantly increase in serum inflammatory cytokines IL-1 and IL-10, and a decrease in IL-6. Both STAT3 protein and mRNA levels were significantly lower in the MgIG treated groups than in the control group at 6 h, 12 h, and 18 h after surgery.

CONCLUSION: High-dose MgIG can extend survival time in rats after excessive hepatectomy. This hepatoprotective effect is mediated by inhibiting the inflammatory response through inhibition of the STAT3 pathway.