Pancreatic secretory trypsin inhibitor: More than a trypsin inhibitor

Inducible, but not constitutive, pancreatic REG/Reg isoforms are regulated by intestinal microbiota and pancreatic diseases

The REG/Reg gene locus encodes a conserved family of potent antimicrobial but also pancreatitis-associated proteins. Here we investigated whether REG/Reg family members differ in their baseline expression levels and abilities to be regulated in the pancreas and gut upon perturbations. We found, in humans and mice, the pancreas and gut differed in REG/Reg isoform levels and preferences, with the duodenum most resembling the pancreas. Pancreatic acinar cells and intestinal enterocytes were the dominant REG producers. Intestinal symbiotic microbes regulated the expression of the same, select Reg members in gut and pancreas. These Reg members had the most STAT3-binding sites close to the transcription start sites and were partially IL-22 dependent. We thus categorized them as "inducible" and others as "constitutive". Indeed, in pancreatic ductal adenocarcinoma and pancreatitis models, only inducible Reg members were upregulated in the pancreas. While intestinal Reg expression remained unchanged upon pancreatic perturbation, pancreatitis altered the microbial composition of the duodenum and feces shortly after disease onset. Our study reveals differential usage and regulation of REG/Reg isoforms as a mechanism for tissue-specific innate immunity, highlights the intimate connection of pancreas and duodenum, and implies a gut-to-pancreas communication axis resulting in a coordinated Reg response.

Study of a panel of genetic mutations in fibrocalcific pancreatic diabetes (FCPD): SPINK1 (N34S) mutation unlikely to be relevant

Panel of known genetic mutations (SPINK1, PRSS1, PRSS2, CTRC, and CFTR) in patients with Fibrocalcific pancreatic diabetes (FCPD)compared to Type 2 Diabetes (T2DM) and healthy controls with emphasis on SPINK1 (N34S) mutations. Whole blood samples were used to detect mutations by PCR followed by Sanger sequencing. In-silico analysis of N34S performed, to explore role in pathogenesis. Isolated SPINK1 N34S mutations found in 5.88%, 6% and 2% in FCPD, T2DM, controls respectively (p = ns). In-silico analysis of N34S variant: conflicting role. 2/51 (3.92%) SPINK1 (IVS1-37 T > C) positive, 2/51 (3.92%) SPINK1 P55S positive, 1/51 (2%) SPINK 1 (IVS3 + 2 T > C) positive and none of them SPINK1 (IV3-69insTTT) positive and none of these variants found in T2DM & healthy individuals. PRSS1, CTRC exon 2-3 mutation was found 4/51 (7.8%) and 1/51 (2%) patients of FCPD respectively. None of the patient had mutations in PRSS2, CTRC Promoter region & exon 1, CTRC exon 4-5, CTRC exon 6, CTRC exon 7-8, CFTR ΔF508, CFTR G551D, CFTR G542X, CFTR R117H and CFTR W1282X. Different variants of SPINK1, PRRS1 and CTRC were found in FCPD. Isolated SPINK1 N34S unlikely to cause disease by itself.

Inducible, but not constitutive, pancreatic REG/Reg isoforms are regulated by intestinal microbiota and pancreatic diseases

The REG / Reg gene locus encodes for a conserved family of potent antimicrobial but also pancreatitis-associated proteins. Here we investigated whether REG/Reg family members differ in their baseline expression levels and abilities to be regulated in the pancreas and gut upon perturbations. We found, in human and mouse, pancreas and gut differed in REG / Reg isoform levels and preferences, with duodenum most resembling the pancreas. Pancreatic acinar cells and intestinal enterocytes were the dominant REG producers. Intestinal symbiotic microbes regulated the expression of the same, select Reg members in gut and pancreas. These Reg members had the most STAT3-binding sites close to the transcription start sites and were partially IL-22 dependent. We thus categorized them as "inducible" and others as "constitutive". Indeed, also in models of pancreatic-ductal adenocarcinoma and pancreatitis, only inducible Reg members were upregulated in pancreas. While intestinal Reg expression remained unchanged upon pancreatic perturbation, pancreatitis altered the microbial composition of the duodenum and feces shortly after disease onset. Our study reveals differential usage and regulation of REG / Reg isoforms as a mechanism for tissue-specific innate immunity, highlights the intimate connection of pancreas and duodenum, and implies a gut-to-pancreas communication axis resulting in a coordinated Reg response.

Tumor-associated macrophages: The key player in hepatoblastoma microenvironment and the promising therapeutic target

The tumor microenvironment of hepatoblastoma (HB), the most common pediatric liver tumor, predominantly exhibits a myeloid immune landscape. in which tumor-associated macrophages (TAMs) are considered the core component. The crosstalk between TAMs and HB cells markedly influences tumor behavior. TAM-derived factors are involved in tumor proliferation and vascular invasion. On the other hand, HB cell secretome attracts, stimulates, and reprograms TAMs to be immunosuppressive in favor of tumor invasion, rather than their innate role in combating tumor growth, such crosstalk sometimes forms bidirectional feedback loops, making the tumor more virulent and resistant to routine therapeutics. Consequently, TAMs are the common denominator of most suggested HB immunotherapeutic strategies. Macrophage immune checkpoint inhibitors, macrophage-mediated antibody-dependent cellular phagocytosis, and the novel chimeric antigen receptor macrophage therapy (CAR Mφ) are currently under trial. In this review, we will summarize the significance of TAMs and their potential role as a therapeutic target in HB.

Growth Performance, Feed Utilisation, Endogenous Digestive Enzymes, Intestinal Morphology, and Antimicrobial Effect of Pacific White Shrimp (Litopenaeus vannamei) Fed with Feed Supplemented with Pineapple Waste Crude Extract as a Functional Feed Additive

This study used pineapple waste crude extract (PWCE) to increase the potential of Pacific white shrimp (Litopenaeus vannamei) production for food sustainability and stability. The objective was to investigate the appropriate technique to increase the yield production and quality of shrimp and decrease waste from shrimp culture. Pacific white shrimp (average body size: 0.51 g) were fed with commercial feed supplemented with PWCE at various concentrations of 0 (control), 90, 170, and 250 ppt. Shrimp were fed five times per day for 80 days. At the end of the trial, the results showed that shrimp fed with the PWCE 250 ppt supplementation provided the highest growth rate and the best feed utilisation and yield (P < 0.05). The protein content of whole shrimp in all shrimp fed with the PWCE supplementation diet was higher than that in the control group (P < 0.05). On the contrary, the variation of endogenous digestive enzymes, including protease, trypsin, and the T/C ratio, was significantly lower in shrimp fed a diet supplemented with PWCE 250 ppt (P < 0.05). While in this group, the number of microorganisms on thiosulfate-citrate-bile salt-sucrose (TCBS), blood agar, and trypticase soy agar (TSA) was lowest (P < 0.05). Furthermore, the dietary PWCE at 250 ppt increased the volume of microvilli in the hindgut of shrimp, but the supplementation at 170 ppt improved the number of F-cells in the epithelial cells of the hepatopancreas. Nevertheless, the supplementation of PWCE in the diet did not affect the water quality (P > 0.05). Therefore, pineapple waste crude extract supplementation improves both quantitative and qualitative yields and tends to reduce waste.

Single-cell profiling of GP2-enriched pancreatic progenitors to simultaneously create acinar, ductal, and endocrine organoids

Rationale: Pancreatic lineage specification follows the formation of tripotent pancreatic progenitors (PPs). Current protocols rebuilding PPs in vitro have an endocrine lineage bias and are mostly based on PDX1/NKX6-1 coexpression neglecting other markers decisive for PP heterogeneity and lineage potential. However, true tripotent PPs are of utmost interest to study also exocrine disorders such as pancreatic cancer and to simultaneously generate all three pancreatic lineages from the same ancestor. Methods: Here, we performed a comprehensive compound testing to advance the generation of multipotent progenitors, which were further characterized for their trilineage potential in vitro and in vivo. The heterogeneity and cell-cell communication across the PP subpopulations were analyzed via single-cell transcriptomics. Results: We introduce a novel PP differentiation platform based on a comprehensive compound screening with an advanced design of experiments computing tool to reduce impurities and to increase Glycoprotein-2 expression and subsequent trilineage potential. Superior PP tripotency was proven in vitro by the generation of acinar, endocrine, and ductal cells as well as in vivo upon orthotopic transplantation revealing all three lineages at fetal maturation level. GP2 expression levels at PP stage ascribed varying pancreatic lineage potential. Intermediate and high GP2 levels were superior in generating endocrine and duct-like organoids (PDLO). FACS-based purification of the GP2^high PPs allowed the generation of pancreatic acinar-like organoids (PALO) with proper morphology and expression of digestive enzymes. scRNA-seq confirmed multipotent identity, positioned the GP2/PDX1/NKX6-1^high population next to human fetal tip and trunk progenitors and identified novel ligand-receptor (LR) interactions in distinct PP subpopulations. LR validation experiments licensed midkine and VEGF signaling to increase markers labelling the single cell clusters with high GP2 expression. Conclusion: In this study, we guide human pluripotent stem cells into multipotent pancreatic progenitors. This common precursor population, which has the ability to mature into acinar, ductal and functional β-cells, serves as a basis for studying developmental processes and deciphering early cancer formation in a cell type-specific context. Using single-cell RNA sequencing and subsequent validation studies, we were able to dissect PP heterogeneity and specific cell-cell communication signals.

Inflammation-like changes in the urothelium of Lifr-deficient mice and LIFR-haploinsufficient humans with urinary tract anomalies

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of end-stage kidney disease in children. While the genetic aberrations underlying CAKUT pathogenesis are increasingly being elucidated, their consequences on a cellular and molecular level commonly remain unclear. Recently, we reported rare heterozygous deleterious LIFR variants in 3.3% of CAKUT patients, including a novel de novo frameshift variant, identified by whole-exome sequencing, in a patient with severe bilateral CAKUT. We also demonstrated CAKUT phenotypes in Lifr-/- and Lifr+/- mice, including a narrowed ureteric lumen due to muscular hypertrophy and a thickened urothelium. Here, we show that both in the ureter and bladder of Lifr-/- and Lifr+/- embryos, differentiation of the three urothelial cell types (basal, intermediate and superficial cells) occurs normally but that the turnover of superficial cells is elevated due to increased proliferation, enhanced differentiation from their progenitor cells (intermediate cells) and, importantly, shedding into the ureteric lumen. Microarray-based analysis of genome-wide transcriptional changes in Lifr-/- versus Lifr+/+ ureters identified gene networks associated with an antimicrobial inflammatory response. Finally, in a reverse phenotyping effort, significantly more superficial cells were detected in the urine of CAKUT patients with versus without LIFR variants indicating conserved LIFR-dependent urinary tract changes in the murine and human context. Our data suggest that LIFR signaling is required in the epithelium of the urinary tract to suppress an antimicrobial response under homeostatic conditions and that genetically induced inflammation-like changes underlie CAKUT pathogenesis in Lifr deficiency and LIFR haploinsufficiency.

Plasma biomarkers of the amyloid pathway are associated with geographic atrophy secondary to age-related macular degeneration

Geographic atrophy (GA) is an advanced form of dry age-related macular degeneration (AMD), in which local inflammation and hyperactivity of the complement pathway have been implicated in its pathophysiology. This study explores whether any surrogate biomarkers are specifically associated with GA. Plasma from subjects with GA, intermediate dry AMD and non-AMD control were evaluated in 2 cohorts. Cohort 1 was assayed in a 320-analyte Luminex library. Statistical analysis was performed using non-parametric and parametric methods (Kruskal-Wallis, principal component analysis, partial least squares and multivariate analysis of variance (MANOVA) and univariate ANCOVAs). Bioinformatic analysis was conducted and identified connections to the amyloid pathway. Statistically significant biomarkers identified in Cohort 1 were then re-evaluated in Cohort 2 using individual ELISA and multiplexing. Of 320 analytes in Cohort 1, 273 were rendered measurable, of which 56 were identified as changing. Among these markers, 40 were identified in univariate ANCOVAs. Serum amyloid precursor protein (sAPP) was analyzed by a separate ELISA and included in further analyses. The 40 biomarkers, sAPP and amyloid-β (Aβ) (1–42) (included for comparison) were evaluated in Cohort 2. This resulted in 11 statistically significant biomarkers, including sAPP and Aβ(1–40), but not Aβ(1–42). Other biomarkers identified included serum proteases- tissue plasminogen activator, tumor-associated trypsinogen inhibitor, matrix metalloproteinases 7 and 9, and non-proteases- insulin-like growth factor binding protein 6, AXL receptor tyrosine kinase, omentin, pentraxin-3 and osteopontin. Findings suggest that there is a preferential processing of APP to Aβ(1–40) over Aβ(1–42), and a potential role for the carboxylase activity of the γ-secretase protein, which preferentially splices sAPPβ to Aβ(1–40). Other markers are associated with the breakdown and remodeling of the extracellular matrix, and loss of homeostasis, possibly within the photoreceptor-retinal pigment epithelium-choriocapillaris complex. These data suggest novel disease pathways associated with GA pathogenesis and could provide potential novel targets for treatment of GA.

Influence of the MUC1 Cell Surface Mucin on Gastric Mucosal Gene Expression Profiles in Response to Helicobacter pylori Infection in Mice

The cell surface mucin MUC1 is an important host factor limiting Helicobacter pylori (H. pylori) pathogenesis in both humans and mice by providing a protective barrier and modulating mucosal epithelial and leukocyte responses. The aim of this study was to establish the time-course of molecular events in MUC1-modulated gene expression profiles in response to H. pylori infection in wild type (WT) and MUC1-deficient mice using microarray-determined mRNA expression, gene network analysis and Ingenuity Pathway Analysis (IPA). A time-course over the first 72 h of infection showed significantly higher mucosal loads of bacteria at 8 h of infection in Muc1^−/− mice compared with WT, confirming its importance in the early stages of infection (P = 0.0003). Microarray analysis revealed 266 differentially expressed genes at one or more time-points over 72 h in the gastric mucosa of Muc1^−/− mice compared with WT control using a threshold of 2-fold change. The SPINK1 pancreatic cancer canonical pathway was strongly inhibited in Muc1^−/− mice compared with WT at sham and 8 h infection (P = 6.08E-14 and P = 2.25 E-19, respectively) but potently activated at 24 and 72 h post-infection (P = 1.38E-22 and P = 5.87E-13, respectively). The changes in this pathway are reflective of higher expression of genes mediating digestion and absorption of lipids, carbohydrates, and proteins at sham and 8 h infection in the absence of MUC1, but that this transcriptional signature is highly down regulated as infection progresses in the absence of MUC1. Uninfected Muc1^−/− gastric tissue was highly enriched for expression of factors involved in lipid metabolism and 8 h infection further activated this network compared with WT. As infection progressed, a network of antimicrobial and anti-inflammatory response genes was more highly activated in Muc1^−/− than WT mice. Key target genes identified by time-course microarrays were independently validated using RT-qPCR. These results highlight the dynamic interplay between the host and H. pylori, and the role of MUC1 in host defense, and provide a general picture of changes in cellular gene expression modulated by MUC1 in a time-dependent manner in response to H. pylori infection.

Serine peptidase inhibitor Kazal type III (SPINK3) promotes BRL-3A cell proliferation by targeting the PI3K-AKT signaling pathway

The serine protease inhibitor, Kazal type III (SPINK3), is a trypsin inhibitor associated with liver disease, which highly overexpresses in a variety of cancers. In one of our previous studies of our laboratory, Spink3 was observed to be significantly upregulated in rat liver regeneration (LR) via a gene expression profile. For the current study, rat hepatocyte BRL-3A cells were treated by gene addition/interference, and the addition of the exogenous rat recombinant protein SPINK3. It was revealed that both the overexpression of endogenous Spink3 and addition of exogenous rat recombinant SPINK3 (rrSPINK3) significantly promoted the cell proliferation of BRL-3A cells, whereas cell proliferation was inhibited when Spink3 was interfered. Furthermore, quantitative reverse transcription polymerase chain reaction and western blot results revealed that three signaling pathways, including extracellular-signal-regulated kinase 1/2 (ERK1/2), Janus kinase (JAK)-signal transducer and activator of transcription (STAT), and phosphatidylinositol-3-kinase (PI3K)-protein kinase B (AKT), as well as their related genes, were altered following endogenous Spink3 addition/interference. Also, the PI3K-AKT and SRC-p38 pathways and their related genes were modified following exogenous SPINK3 treatment. Among them, the common signaling pathway was PI3K-AKT pathway. We concluded that SPINK3 could activate the PI3K-AKT pathway by enhancing the expression of AKT1 to regulate the proliferation of BRL-3A cells. This study may contribute to shedding light on the potential mechanisms of SPINK3 that regulate the proliferation of BRL-3A cells.

Regulation of the Pancreatic Exocrine Differentiation Program and Morphogenesis by Onecut 1/Hnf6

BACKGROUND & AIMS

The Onecut 1 transcription factor (Oc1, a.k.a. HNF6) promotes differentiation of endocrine and duct cells of the pancreas; however, it has no known role in acinar cell differentiation. We sought to better understand the role of Oc1 in exocrine pancreas development and to identify its direct transcriptional targets.

METHODS

Pancreata from Oc1^Δpanc (Oc1^fl/fl;Pdx1-Cre) mouse embryos and neonates were analyzed morphologically. High-throughput RNA-sequencing was performed on control and Oc1-deficient pancreas; chromatin immunoprecipitation sequencing was performed on wild-type embryonic mouse pancreata to identify direct Oc1 transcriptional targets. Immunofluorescence labeling was used to confirm the RNA-sequencing /chromatin immunoprecipitation sequencing results and to further investigate the effects of Oc1 loss on acinar cells.

RESULTS

Loss of Oc1 from the developing pancreatic epithelium resulted in disrupted duct and acinar cell development. RNA-sequencing revealed decreased expression of acinar cell regulatory factors (Nr5a2, Ptf1a, Gata4, Mist1) and functional genes (Amylase, Cpa1, Prss1, Spink1) at embryonic day (e) 18.5 in Oc1^Δpanc samples. Approximately 1000 of the altered genes were also identified as direct Oc1 targets by chromatin immunoprecipitation sequencing, including most of the previously noted genes. By immunolabeling, we confirmed that Amylase, Mist1, and GATA4 protein levels are significantly decreased by P2, and Spink1 protein levels were significantly reduced and mislocalized. The pancreatic duct regulatory factors Hnf1β and FoxA2 were also identified as direct Oc1 targets.

CONCLUSIONS

These findings confirm that Oc1 is an important regulator of both duct and acinar cell development in the embryonic pancreas. Novel transcriptional targets of Oc1 have now been identified and provide clarity into the mechanisms of Oc1 transcriptional regulation in the developing exocrine pancreas. Oc1 can now be included in the gene-regulatory network of acinar cell regulatory genes. Oc1 regulates other acinar cell regulatory factors and acinar cell functional genes directly, and it can also regulate some acinar cell regulatory factors (eg, Mist1) indirectly. Oc1 therefore plays an important role in acinar cell development.

Gene Signature of the Human Pancreatic ε Cell

The ghrelin-producing ε cell represents the fifth endocrine cell type in human pancreatic islets. The abundance of ε cells in adult pancreas is extremely low, which has hampered the investigation on the molecular pathways regulating the development and the function of this cell type. In this study, we explored the molecular features defining the function of pancreatic ε cells isolated from adult nondiabetic donors using single-cell RNA sequencing technology. We focus on transcription factors, cell surface receptors, and genes involved in metabolic pathways that contribute to regulation of cellular function. Furthermore, the genes that separate ε cells from the other islet endocrine cell types are presented. This study expands prior knowledge about the genes important for ε cell functioning during development and provides a resource to interrogate the transcriptome of this rare human islet cell type.

Surgical decompression of Wirsung duct reduces serum concentration of SPINK1 in patients with chronic pancreatitis

OBJECTIVES

The primary aim of this study was to determine the blood levels of SPINK1 in patients with chronic pancreatitis (CP) submitted to surgical or endoscopic decompression of pancreatic duct (PD). Additionally, we measured trypsin activity levels.

METHODS

Two groups were identified, surgical (group A) and endoscopic (group B). Levels of SPINK1 and trypsin activity were measured at baseline and 6 months after pancreatic duct decompression and then compared within the groups. SPINK1 levels were determined with Human ELISA Kit.

RESULTS

Group A and B were made up of 30 and 28 patients, respectively. Baseline features of the groups were similar. A decrease in SPINK1 levels was significant only in group A 46.88 to 16.10 ng/mL (p = 0.001). On the contrary, trypsin activity changed significantly in group B 40.01 to 34.92 mU/mL (p = 0.01). Patients of group A showed a significant increase in BMI, before and after treatment. The pain score pre- and post-treatment reduced significantly in both groups (p < 0.001).

CONCLUSIONS

We demonstrate for the first time a significant decrease of SPINK1 levels after surgical decompression of PD and a reduction of trypsin activity analysis after endoscopic decompression. The meaning of this phenomena is yet to be explained and it should be further explored.

Transcriptomic features of primary prostate cancer and their prognostic relevance to castration-resistant prostate cancer

Although various mechanisms of castration-resistant prostate cancer (CRPC) have been discovered, reliable biomarkers for monitoring CRPC progression are lacking. We sought to identify molecules that predict the progression of advanced prostate cancer (AdvPC) into CRPC. The study used primary-site samples (N=45 for next-generation sequencing (NGS); N=243 for real-time polymerase chain reaction) from patients with prostate cancer (PC). Five public databases containing microarray data of AdvPC and CRPC samples were analyzed. The NGS data showed that each progression step in PC associated with distinct gene expression profiles. Androgen receptor (AR) associated with tumorigenesis, advanced progression, and progression into CRPC. Analysis of the paired and unpaired AdvPC and CRPC samples in the NGS cohort showed that 15 genes associated with progression into CRPC. This was validated by cohort-1 and public database analyses. Analysis of the third cohort with AdvPC showed that higher serine peptidase inhibitor, Kazal type 1 (SPINK1) and lower Sp8 transcription factor (SP8) expression associated with progression into CRPC (log-rank test, both P<0.05). Multivariate regression analysis showed that higher SPINK1 (Hazard Ratio (HR)=4.506, 95% confidence intervals (CI)=1.175-17.29, P=0.028) and lower SP8 (HR=0.199, 95% CI=0.063-0.632, P=0.006) expression independently predicted progression into CRPC. Gene network analysis showed that CRPC progression may be mediated through the AR-SPINK1 pathway by a HNF1A-based gene network. Taken together, our results suggest thatSPINK1 and SP8 may be useful for classifying patients with AdvPC who have a higher risk of progressing to CRPC.

SPINK1 Promoter Variants Are Associated with Prostate Cancer Predisposing Alterations in Benign Prostatic Hyperplasia Patients

BACKGROUND/AIM

Several studies reported that patients with benign prostatic hyperplasia (BPH) experienced a 10% increased incidence of prostate cancer (PCa) after the first 5 years of diagnosis. We investigated the association between single nucleotide polymorphisms (SNPs) in the promoter of Serine Protease Inhibitor Kazal Type 1 (SPINK1) and the increased risk of BPH and PCa.

MATERIALS AND METHODS

We genotyped three SNPs in a cases-control study, including BPH and PCa cases. Multiple logistic regression models were applied to analyze clinical and genotypic data.

RESULTS

We found an inverse association between SNP rs10035432 and BPH under the log-additive (p=0.007) model. No association was found between these SNPs and PCa risk. However, we observed a possible association between rs1432982 and lower-grade PCa (p=0.05) under the recessive model.

CONCLUSION

SPINK1 promoter variants are likely to be associated with the risk of BPH.

Cloning and prokaryotic expression of rat homolog of Serpina3n and its expression change during liver regeneration

A strikingly upregulated expressed sequence tag was screened from regenerating rat liver at 8 h in a 0-4-8-12 h short-interval successive partial hepatectomy model from a previous study. In the present study, a full-length open reading frame (ORF) corresponding to this expressed sequence tag was predicted through electronic cloning and was subsequently cloned from an 8-h rat regenerating liver and deposited in GenBank (accession No. HM448398). Sequence analysis of HM448398 and the predicted ORF revealed that the two ORFs may be different transcripts of a gene. The sequence of HM448398 was highly homologous to that of rat Serpina3n, suggesting that it may be a homolog of Serpina3n. The pGEX-2TK prokaryotic expression vector for this ORF was constructed, and the result of sodium dodecyl sulfate polyacrylamide gel electrophoresis manifested that the recombinant expression vector could express the glutathione-S-transferase-fused rat homolog of Serpina3n in an insoluble form in BL21. The target fusion protein was purified with affinity chromatography and was used as antigen to immunize rabbits for the production of polyclonal antibodies. Immunohistochemistry and real-time reverse transcription polymerase chain reaction analysis revealed that the gene was highly expressed in the priming and termination phases of liver regeneration. These findings lay a solid foundation for further study of roles of HM448398 using knock-in and RNA interference methods during liver regeneration.