STK4 regulates TLR pathways and protects against chronic inflammation-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is frequently associated with pathogen infection-induced chronic inflammation. Large numbers of innate immune cells are present in HCCs and can influence disease outcome. Here, we demonstrated that the tumor suppressor serine/threonine-protein kinase 4 (STK4) differentially regulates TLR3/4/9-mediated inflammatory responses in macrophages and thereby is protective against chronic inflammation-associated HCC. STK4 dampened TLR4/9-induced proinflammatory cytokine secretion but enhanced TLR3/4-triggered IFN-β production via binding to and phosphorylating IL-1 receptor-associated kinase 1 (IRAK1), leading to IRAK1 degradation. Notably, macrophage-specific Stk4 deletion resulted in chronic inflammation, liver fibrosis, and HCC in mice treated with a combination of diethylnitrosamine (DEN) and CCl4, along with either LPS or E. coli infection. STK4 expression was markedly reduced in macrophages isolated from human HCC patients and was inversely associated with the levels of IRAK1, IL-6, and phospho-p65 or phospho-STAT3. Moreover, serum STK4 levels were specifically decreased in HCC patients with high levels of IL-6. In STK4-deficient mice, treatment with an IRAK1/4 inhibitor after DEN administration reduced serum IL-6 levels and liver tumor numbers to levels similar to those observed in the control mice. Together, our results suggest that STK4 has potential as a diagnostic biomarker and therapeutic target for inflammation-induced HCC.

Synonymous codon selection in the hepatitis B virus translation initiation region

Hepatitis B virus (HBV) infection is a major health problem worldwide. This virus and its hosts are often fated to continual co-evolutionary interactions. Codon usage analysis has significance for studies of co-evolution between viruses, their hosts, and mRNA translation. Adaptation of the overall codon usage pattern of HBV to that of humans is estimated using the synonymous codon usage value (RSCU), and the synonymous codon usage biases for the translation initiation region (TIR) of HBV are analyzed by calculation of the usage fluctuation of each synonymous codon along the TIR (the first 50 codon sites of the whole coding sequence of HBV). With respect to synonymous codon usage, our results demonstrated that HBV had no significant tendency to select over-represented codons, but had a significant tendency to select certain under-represented codons in the viral genome. Within the three common HBV hosts, 14 of 59 codons had a similar usage pattern, suggesting that mutation pressure from this DNA virus played an important role in the formation of virus synonymous codon usage. In addition, there was no obvious trend for the codons with relatively low energy to be highly selected in the TIR of HBV, suggesting that the synonymous codon usage patterns for the TIR might not be affected by the nucleotide sequence secondary structure; however, synonymous codon usage in the TIR of HBV was influenced by the overall codon usage patterns of the hosts to some degree. Our results suggest that mutation pressure from HBV plays an important role in the formation of synonymous codon usage of the viral genome, while translation selection from the hosts contributes to virus translational fine-tuning.

High salt primes a specific activation state of macrophages, M(Na)

High salt is positively associated with the risk of many diseases. However, little is known about the mechanisms. Here we showed that high salt increased proinflammatory molecules, while decreased anti-inflammatory and proendocytic molecules in both human and mouse macrophages. High salt also potentiated lipopolysaccharide-induced macrophage activation and suppressed interleukin 4-induced macrophage activation. High salt induced the proinflammatory aspects by activating p38/cFos and/or Erk1/2/cFos pathways, while inhibited the anti-inflammatory and proendocytic aspects by Erk1/2/signal transducer and activator of transcription 6 pathway. Consistent with the in vitro results, high-salt diet increased proinflammatory gene expression of mouse alveolar macrophages. In mouse models of acute lung injury, high-salt diet aggravated lipopolysaccharide-induced pulmonary macrophage activation and inflammation in lungs. These results identify a novel macrophage activation state, M(Na), and high salt as a potential environmental risk factor for lung inflammation through the induction of M(Na).

Population-based trends in prenatal screening and diagnosis for aneuploidy: a retrospective analysis of 38 years of state-wide data

OBJECTIVE

To analyse population-based trends over the entire history of prenatal testing for aneuploidy.

DESIGN

Retrospective analysis of state-wide data sets.

SETTING

Australian state of Victoria with ~70 000 annual births.

POPULATION

All pregnant women undergoing invasive prenatal testing at <25 weeks' gestation from 1976 to 2013.

METHODS

Analysis of three state-wide data sets: (1) Prenatal diagnosis data set of 119 404 amniocenteses and chorionic villus samplings from 1976 to 2013; (2) central serum screening laboratory data set from 1996 to 2013; (3) government birth statistics from 1976 to 2013.

MAIN OUTCOME MEASURES

Annual numbers and uptake rates of invasive prenatal tests and serum screening, indications for invasive prenatal testing, prenatal diagnoses of aneuploidy, diagnostic yield of invasive tests.

RESULTS

Annual numbers of invasive prenatal tests climbed steadily from 1976, then declined from 2000. In 2013, the number of invasive prenatal tests was the lowest in 25 years, while the number of trisomy 21 diagnoses was the highest ever recorded. Annual uptake of serum screening climbed from 1.6 to 83% over 1996-2013. Results from 2013 showed a high diagnostic yield (15.8%) for a low rate of invasive testing (3.4% of births). Over four decades, the number of invasive procedures performed for each diagnosis of major chromosome abnormality declined from 100 to six.

CONCLUSIONS

This study demonstrates historic reductions in the proportion of women undergoing invasive testing and dramatic improvements in diagnostic yield. Monitoring the impact of new prenatal technologies on this progress remains an important research priority.

TWEETABLE ABSTRACT

Invasive prenatal testing has reached historic lows due to dramatic improvements in Down syndrome screening.

mTOR regulates TLR-induced c-fos and Th1 responses to HBV and HCV vaccines

Although IL-12 plays a critical role in priming Th1 and cytotoxic T lymphocyte (CTL) responses, Toll-like receptor (TLR) signaling only induces low amounts of IL-12 in dendritic cells and macrophages, implying the existence of stringent regulatory mechanisms. In this study, we sought to uncover the mechanisms underlying TLR-induced IL-12 expression and the Th1 response. By systemic screening, we identified a number of protein kinases involved in the regulation of TLRinduced IL-12 expression. In particular, PI3K, ERK, and mTOR play critical roles in the TLR-induced Th1 response by regulating IL-12 and IL-10 production in innate immune cells. Moreover, we identified c-fos as a key molecule that mediates mTOR-regulated IL-12 and IL-10 expression in TLR signaling. Mechanistically, mTOR plays a crucial role in c-fos expression, thereby modulating NFκB binding to promoters of IL-12 and IL-10. By controlling the expression of a special innate gene program, mTOR can specifically regulate the TLR-induced T cell response in vivo. Furthermore, blockade of mTOR by rapamycin efficiently boosted TLR-induced antigen-specific T and B cell responses to HBV and HCV vaccines. Taken together, these results reveal a novel mechanism through which mTOR regulates TLR-induced IL-12 and IL-10 production, contributing new insights for strategies to improve vaccine efficacy.

Hepatic p38α regulates gluconeogenesis by suppressing AMPK

BACKGROUND & AIMS

It is proposed that p38 is involved in gluconeogenesis, however, the genetic evidence is lacking and precise mechanisms remain poorly understood. We sought to delineate the role of hepatic p38α in gluconeogenesis during fasting by applying a loss-of-function genetic approach.

METHODS

We examined fasting glucose levels, performed pyruvate tolerance test, imaged G6Pase promoter activity, as well as determined the expression of gluconeogenic genes in mice with a targeted deletion of p38α in liver. Results were confirmed both in vivo and in vitro by using an adenoviral dominant-negative form of p38α (p38α-AF) and the constitutively active mitogen-activated protein kinase 6, respectively. Adenoviral dominant-negative form of AMP-activated protein kinase α (DN-AMPKα) was employed to test our proposed model.

RESULTS

Mice lacking hepatic p38α exhibited reduced fasting glucose level and impaired gluconeogenesis. Interestingly, hepatic deficiency of p38α did not result in an alteration in CREB phosphorylation, but led to an increase in AMPKα phosphorylation. Adenoviral DN-AMPKα could abolish the effect of p38α-AF on gluconeogenesis. Knockdown of up-steam transforming growth factor β-activated kinase 1 decreased the AMPKα phosphorylation induced by p38α-AF, suggesting a negative feedback loop. Consistently, inverse correlations between p38 and AMPKα phosphorylation were observed during fasting and in diabetic mouse models. Importantly, adenoviral p38α-AF treatment ameliorated hyperglycemia in diabetic mice.

CONCLUSIONS

Our study provides evidence that hepatic p38α functions as a negative regulator of AMPK signaling in maintaining gluconeogenesis, dysregulation of this regulatory network contributes to unrestrained gluconeogenesis in diabetes, and hepatic p38α could be a drug target for hyperglycemia.

miR-27b synergizes with anticancer drugs via p53 activation and CYP1B1 suppression

Liver and kidney cancers are notorious for drug resistance. Due to the complexity, redundancy and interpatient heterogeneity of resistance mechanisms, most efforts targeting a single pathway were unsuccessful. Novel personalized therapies targeting multiple essential drug resistance pathways in parallel hold a promise for future cancer treatment. Exploiting the multitarget characteristic of microRNAs (miRNAs), we developed a new therapeutic strategy by the combinational use of miRNA and anticancer drugs to increase drug response. By a systems approach, we identified that miR-27b, a miRNA deleted in liver and kidney cancers, sensitizes cancer cells to a broad spectrum of anticancer drugs in vitro and in vivo. Functionally, miR-27b enhances drug response by activating p53-dependent apoptosis and reducing CYP1B1-mediated drug detoxification. Notably, miR-27b promotes drug response specifically in patients carrying p53-wild-type or CYP1B1-high signature. Together, we propose that miR-27b synergizes with anticancer drugs in a defined subgroup of liver and kidney cancer patients.

Association of polymorphisms of the xeroderma pigmentosum complementation group F gene with increased glioma risk

We aimed to investigate the role of 4 single nucleotide polymorphisms of the xeroderma pigmentosum complementation group F (XPF) gene (rs3136038, rs1799798, rs1800067, and rs2276466) in glioma, and the roles of gene-gene interactions in the risk of developing this type of cancer. We collected samples from 225 glioma cases and 262 controls and genotyped the rs3136038, rs1799798, rs1800067, and rs2276466 polymorphisms using a 384-well plate format with the Sequenom MassARRAY platform. Individuals carrying the rs1800067 GG genotype were more likely to have an increased risk of glioma when compared with carriers of the A/A genotype in a co-dominant model, with an odds ratio (OR) [95% confidence interval (CI)] of 2.85 (1.14-7.76). However, we did not find an association with increased risk of glioma for the polymorphisms rs3136038, rs1799798, and rs2276466 in XPF. The combination genotype of the rs1800067 G allele and the rs2276466 G allele was associated with a moderate risk of glioma (OR = 1.71, 95%CI = 1.02-2.87). Our study suggests that the rs1800067 genetic variant of XPF functions in the development of glioma.

Fluid resuscitation and standard drug treatment strategies in heatstroke Chinese patients

The objective of the present study was to evaluate different stage fluid and standard drug treatment strategies in 47 heatstroke patients. 47 adults with Heatstroke received fluid resuscitation treatment guided by transpulmonary thermodilution (PiCCO) in our intensive care unit. Systemic hemodynamics, microvascular indices and measures of acidosis, renal function, and pulmonary edema were followed prospectively. The speed of recovery and the component change was compared during the 6 h, 48 h and 96 h after the 3 stage fluid therapy. All patients were hyperpyrexia (core temperature>41°C), and on ventilation when enrolled in the ICU. Patients received a 6.17 (±1.8) ml/kg/h of crystal fluid and 3.31 (±0.5) ml/kg/h of colloidal fluid in the first 6 h; (3.41±1.2) ml/kg/h crystal fluid along with 2.27 (±0.3) ml/kg/h colloidal fluid in the first 48 h; 2.27 (±0.6) ml/kg/h crystal fluid along with 2.06 (±0.3) ml/kg/h colloidal fluid in the next 48 h. With resuscitation, acid-base status deteriorated in 25 of 47 patients (53.1%), extravascular lung water increased in 36 of 47 resuscitated patients (77%); 21 of these patients developed pulmonary edema though guided by transpulmonary thermodilution, 30 (63.8%) patients survived. All patients with pulmonary edema during the study were hypovolemic or euvolemic at the time pulmonary edema developed. Plasma lactate was lower in hypovolemic patients before (p<0.05) and after (p<0.05) resuscitation. Acute kidney injury was evident in 21 of 47 patients (47%) 48 h after enrollment. In conclusion, our study revealed that fluid resuscitation post heatstroke should be adjusted according to different stages.

Direct reprogramming of human fibroblasts to functional and expandable hepatocytes

The generation of large numbers of functional human hepatocytes for cell-based approaches to liver disease is an important and unmet goal. Direct reprogramming of fibroblasts to hepatic lineages could offer a solution to this problem but so far has only been achieved with mouse cells. Here, we generated human induced hepatocytes (hiHeps) from fibroblasts by lentiviral expression of FOXA3, HNF1A, and HNF4A. hiHeps express hepatic gene programs, can be expanded in vitro, and display functions characteristic of mature hepatocytes, including cytochrome P450 enzyme activity and biliary drug clearance. Upon transplantation into mice with concanavalin-A-induced acute liver failure and fatal metabolic liver disease due to fumarylacetoacetate dehydrolase (Fah) deficiency, hiHeps restore the liver function and prolong survival. Collectively, our results demonstrate successful lineage conversion of nonhepatic human cells into mature hepatocytes with potential for biomedical and pharmaceutical applications.

Overall codon usage pattern of enterovirus 71

Hand, foot, and mouth disease (HFMD) is a systemic illness in children and is usually caused by enterovirus 71 (EV71). To provide new insights into the genetic features of EV71 and the relationship between the overall codon usage pattern of this virus and that of humans, values for relative synonymous codon usage (RSCU), effective number of codons (ENC), codon adaptation index (CAI), and nucleotide composition were calculated and analyzed. The relationship between ENC values and (G+C)₃% suggests that, although nucleotide composition plays an important role in shaping the overall codon usage pattern of this virus, other factors also affect this pattern. In addition, the negative correlation between the CAI value and (G+C)₃% suggests that the secondary structure of the EV71 coding sequence caused by its nucleotide composition can affect gene expression. Moreover, there was no significant correlation between ENC and CAI, suggesting that gene expression does not play a role in shaping the overall codon usage pattern of EV71. The overall codon usage pattern of the EV71 virus is only partly similar to the general codon pattern of human, suggesting that, although EV71 has co-evolved with humans for extended periods, mutation pressure played an important role in shaping the virus's overall codon usage pattern. These results revealed that the EV71 virus has developed a subtle strategy during evolution for adapting to environmental changes in its host cells solely by means of mutation pressure.

Hepatic loss of survivin impairs postnatal liver development and promotes expansion of hepatic progenitor cells in mice

Hepatocytes possess a remarkable capacity to regenerate and reconstitute the parenchyma after liver damage. However, in the case of chronic injury, their proliferative potential is impaired and hepatic progenitor cells (HPCs) are activated, resulting in a ductular reaction known as oval cell response. Proapoptotic and survival signals maintain a precise balance to spare hepatocytes and progenitors from hyperplasia and cell death during regeneration. Survivin, a member of the family of inhibitor of apoptosis proteins (IAPs), plays key roles in the proliferation and apoptosis of various cell types. Here, we characterized the in vivo function of Survivin in regulating postnatal liver development and homeostasis using mice carrying conditional Survivin alleles. Hepatic perinatal loss of Survivin causes impaired mitosis, increased genome ploidy, and enlarged cell size in postnatal livers, which eventually leads to hepatocyte apoptosis and triggers tissue damage and inflammation. Subsequently, HPCs that retain genomic Survivin alleles are activated, which finally differentiate into hepatocytes and reconstitute the whole liver. By contrast, inducible ablation of Survivin in adult hepatocytes does not affect HPC activation and liver homeostasis during a long-life period.

CONCLUSION

Perinatal Survivin deletion impairs hepatic mitosis in postnatal liver development, which induces HPC activation and reconstitution in the liver, therefore providing a novel HPC induction model.

The m subunit of murine translation initiation factor eIF3 maintains the integrity of the eIF3 complex and is required for embryonic development, homeostasis, and organ size control

Mammalian eIF3 is composed of 13 subunits and is the largest eukaryotic initiation factor. eIF3 plays a key role in protein biosynthesis. However, it is not fully understood how different subunits contribute to the structural integrity and function of the eIF3 complex. Whether eIF3 is essential for embryonic development and homeostasis is also not known. Here, we show that eIF3m null embryos are lethal at the peri-implantation stage. Compound heterozygotes (eIF3m(flox)(/-)) or FABP4-Cre-mediated conditional knock-out mice are lethal at mid-gestation stages. Although the heterozygotes are viable, they show markedly reduced organ size and diminished body weight. Acute ablation of eIF3m in adult mouse liver leads to rapidly decreased body weight and death within 2 weeks; these effects are correlated with a severe decline of protein biogenesis in the liver. Protein analyses reveal that eIF3m deficiency significantly impairs the integrity of the eIF3 complex due to down-regulation of multiple other subunits. Two of the subunits, eIF3f and eIF3h, are stabilized by eIF3m through subcomplex formation. Therefore, eIF3m is required for the structural integrity and translation initiation function of eIF3. Furthermore, not only is eIF3m an essential gene, but its expression level is also important for mouse embryonic development and the control of organ size.

Cell fate conversion: direct induction of hepatocyte-like cells from fibroblasts

One of the essential features of stem cells is their cellular plasticity to differentiate into daughter cells with defined functions. Recently, induction of pluripotent stem cells from somatic cells by defined transcription factors led to the focus on cellular plasticity of terminally differentiated cells. This approach is adopted by other studies to demonstrate the cell fate conversion between different lineages of terminally differentiated cells. We and others showed that induced hepatocyte-like (iHep) cells are directly converted from mouse fibroblasts by overexpression of liver-enriched transcription factors. iHep cells as well as pluripotent stem cell- or mesenchymal stem cell-derived hepatocyte-like cells provide potential cell sources for disease modeling, transplantation, and tissue engineering independent of donor organs. Here, we review the latest advances in generating hepatocyte-like cells and summarize general criteria for evaluating these cells. In addition, we propose a possible role of the p19(Arf) /p53 pathway in cell fate maintenance, which apparently limits the formation of induced pluripotent stem (iPS) cells and iHep cells.