BI-3231, an enzymatic inhibitor of HSD17B13, reduces lipotoxic effects induced by palmitic acid in murine and human hepatocytes.

17-ß-hydroxysteroid dehydrogenase 13 (HSD17B13), a lipid droplet-associated enzyme, is primarily expressed in the liver and plays an important role in lipid metabolism. Targeted inhibition of enzymatic function is a potential therapeutic strategy for treating steatotic liver disease (SLD). The present study is aimed at investigating the effects of the first selective HSD17B13 inhibitor, BI-3231, in a model of hepatocellular lipotoxicity using human cell lines and primary mouse hepatocytes in vitro. Lipotoxicity was induced with palmitic acid in HepG2 cells and freshly isolated mouse hepatocytes and the cells were coincubated with BI-3231 to assess the protective effects. Under lipotoxic stress, triglyceride (TG) accumulation was significantly decreased in the BI-3231-treated cells compared with that of the control untreated human and mouse hepatocytes. In addition, treatment with BI-3231 led to considerable improvement in hepatocyte proliferation, cell differentiation, and lipid homeostasis. Mechanistically, BI-3231 increased the mitochondrial respiratory function without affecting ß-oxidation. BI-3231 inhibited the lipotoxic effects of palmitic acid in hepatocytes, highlighting the potential of targeting HSD17B13 as a specific therapeutic approach in steatotic liver disease.NEW & NOTEWORTHY 17-ß-Hydroxysteroid dehydrogenase 13 (HSD17B13) is a lipid droplet protein primarily expressed in the liver hepatocytes. HSD17B13 is associated with the clinical outcome of chronic liver diseases and is therefore a target for the development of drugs. Here, we demonstrate the promising therapeutic effect of BI-3231 as a potent inhibitor of HSD17B13 based on its ability to inhibit triglyceride accumulation in lipid droplets (LDs), restore lipid metabolism and homeostasis, and increase mitochondrial activity in vitro.

Decreases in cT1 and liver fat content reflect treatment-induced histological improvements in MASH.

BACKGROUND & AIMS: MRI biomarkers of liver disease are robust and reproducible alternatives to liver biopsy. Emerging data suggest that absolute reduction in iron corrected T1 (cT1) of ≥ 80 ms and relative reduction in liver fat content of 30% reflect histological improvement. We aimed to validate the associations of changes to these noninvasive biomarkers with histological improvement, specifically the resolution of steatohepatitis. METHODS: A retrospective analysis of participants from three interventional clinical trials who underwent multiparametric MRI to measure liver cT1 and liver fat content (LFC) (LiverMultiScan) alongside biopsies at baseline and end of study. Responders were defined as those achieving resolution of steatohepatitis with no worsening in fibrosis. Differences in the magnitude of change in cT1 and LFC between responders and non-responders was assessed. RESULTS: Individual patient data from 150 participants were included. There was a significant decrease in liver cT1 (-119 ms vs. -49 ms) and liver fat content (-65% vs. -29%) in responders compared to non-responders (P < .001) respectively. The diagnostic accuracy to identify responders was 0.72 (AUC) for both. The Youden's index for cT1 to separate responders from non-responders was -82 ms and for liver fat was a 58% relative reduction. Those achieving a ≥ 80 ms reduction in cT1 were 5-times more likely to achieve histological response (sens 0.68; spec 0.70). Those achieving a 30% relative reduction in liver fat were ∼4 times more likely to achieve a histological response (sens 0.77; spec 0.53). CONCLUSIONS: These results, from three combined drug trials, demonstrate that changes in multiparametric MRI markers of liver health (cT1 and PDFF) can predict histological response for steatohepatitis following therapeutic intervention. IMPACT AND IMPLICATIONS: There is great interest in identifying suitable biomarkers that can be used to replace liver biopsy, or to identify those patients who would benefit from one, in both the clinical management of MASH and in drug development. We investigated the utility of two MRI-derived non-invasive tests, iron corrected T1 mapping (cT1) and liver fat content from proton density fat fraction (PDFF), to predict histological improvement in patients who had undergone experimental treatment for MASH. Using data from 150 people who participated in one of three clinical trials, we observed that a reduction in cT1 by over 80 ms and a relative reduction in PDFF of over 58% were the optimal thresholds for change that predicted resolution of steatohepatitis. PDFF as a marker of liver fat, and cT1 as a specific measure of liver disease activity, are both effective at identifying those who are likely responding to drug interventions and experiencing improvements in overall liver health. CLINICAL TRIAL NUMBER(S): NCT02443116, NCT03976401, NCT03551522.

Global survey of stigma among physicians and patients with nonalcoholic fatty liver disease.

BACKGROUND & AIMS: Patients with fatty liver disease may experience stigma from the disease or comorbidities. In this cross-sectional study, we aimed to understand stigma among patients with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) and healthcare providers. METHODS: Members of the Global NASH Council created two surveys about experiences/attitudes toward NAFLD and related diagnostic terms: a 68-item patient and a 41-item provider survey. RESULTS: Surveys were completed by 1,976 patients with NAFLD across 23 countries (51% Middle East/North Africa [MENA], 19% Europe, 17% USA, 8% Southeast Asia, 5% South Asia) and 825 healthcare providers (67% gastroenterologists/hepatologists) across 25 countries (39% MENA, 28% Southeast Asia, 22% USA, 6% South Asia, 3% Europe). Of all patients, 48% ever disclosed having NAFLD/NASH to family/friends; the most commonly used term was "fatty liver" (88% at least sometimes); "metabolic disease" or "MAFLD" were rarely used (never by >84%). Regarding various perceptions of diagnostic terms by patients, there were no substantial differences between "NAFLD", "fatty liver disease (FLD)", "NASH", or "MAFLD". The most popular response was being neither comfortable nor uncomfortable with either term (56%-71%), with slightly greater discomfort with "FLD" among the US and South Asian patients (47-52% uncomfortable). Although 26% of patients reported stigma related to overweight/obesity, only 8% reported a history of stigmatization or discrimination due to NAFLD. Among providers, 38% believed that the term "fatty" was stigmatizing, while 34% believed that "nonalcoholic" was stigmatizing, more commonly in MENA (43%); 42% providers (gastroenterologists/hepatologists 45% vs. 37% other specialties, p = 0.03) believed that the name change to metabolic dysfunction-associated steatotic liver disease (or MASLD) might reduce stigma. Regarding the new nomenclature, the percentage of providers reporting "steatotic liver disease" as stigmatizing was low (14%). CONCLUSIONS: The perception of NAFLD stigma varies among patients, providers, geographic locations and sub-specialties. IMPACT AND IMPLICATIONS: Over the past decades, efforts have been made to change the nomenclature of nonalcoholic fatty liver disease (NAFLD) to better align with its underlying pathogenetic pathways and remove any potential stigma associated with the name. Given the paucity of data related to stigma in NAFLD, we undertook this global comprehensive survey to assess stigma in NAFLD among patients and providers from around the world. We found there is a disconnect between physicians and patients related to stigma and related nomenclature. With this knowledge, educational programs can be developed to better target stigma in NAFLD among all stakeholders and to provide a better opportunity for the new nomenclature to address the issues of stigma.

Genetic risk accentuates dietary effects on hepatic steatosis, inflammation and fibrosis in a population-based cohort.

BACKGROUND & AIMS: Steatotic liver disease (SLD), characterized by elevated liver fat content (LFC), is influenced by genetics and diet. However, whether diet has a differential effect based on genetic risk is not well-characterized. We aimed to determine how genetic factors interact with diet to affect SLD in a large national biobank. METHODS: We included UK Biobank participants with dietary intake measured by 24-hour recall and genotyping. The primary predictors were dietary pattern, PNPLA3-rs738409-G, TM6SF2-rs58542926-T, a 16-variant hepatic steatosis polygenic risk score (PRS), and gene-environment interactions. The primary outcome was LFC, and secondary outcomes were iron-controlled T1 time (cT1, a measure of liver inflammation and fibrosis) and liver-related events/mortality. RESULTS: A total of 21,619 participants met inclusion criteria. In non-interaction models, Mediterranean diet and intake of fruit/vegetables/legumes and fish associated with lower LFC, while higher red/processed meat intake and all genetic predictors associated with higher LFC. In interaction models, all genetic predictors interacted with Mediterranean diet and fruit/vegetable/legume intake, while the steatosis PRS interacted with fish intake and the TM6SF2 genotype interacted with red/processed meat intake, to affect LFC. Dietary effects on LFC were up to 3.8-fold higher in PNPLA3-rs738409-GG vs. -CC individuals, and 1.4-3.0-fold higher in the top vs. bottom quartile of the steatosis PRS. Gene-diet interactions were stronger in participants with vs. without overweight. The steatosis PRS interacted with Mediterranean diet and fruit/vegetable/legume intake to affect cT1 and most dietary and genetic predictors associated with risk of liver-related events or mortality by age 70. CONCLUSIONS: Effects of diet on LFC and cT1 were markedly accentuated in patients at increased genetic risk for SLD, implying dietary interventions may be more impactful in these populations. IMPACT AND IMPLICATIONS: Genetic variants and diet both influence risk of hepatic steatosis, inflammation/fibrosis, and hepatic decompensation; however, how gene-diet interactions influence these outcomes has previously not been comprehensively characterized. We investigated this topic in the community-based UK Biobank and found that genetic risk and dietary quality interacted to influence hepatic steatosis and inflammation/fibrosis on liver MRI, so that the effects of diet were greater in people at elevated genetic risk. These results are relevant for patients and medical providers because they show that genetic risk is not fixed (i.e. modifiable factors can mitigate or exacerbate this risk) and realistic dietary changes may result in meaningful improvement in liver steatosis and inflammation/fibrosis. As genotyping becomes more routinely used in clinical practice, patients identified to be at high baseline genetic risk may benefit even more from intensive dietary counseling than those at lower risk, though future prospective studies are required.

Pharmaco-Economic Assessment of Screening Strategies for High-Risk MASLD in Primary Care.

BACKGROUND AND AIMS: Several scientific associations recommend a sequential combination of non-invasive tests (NITs) to identify high-risk MASLD patients but their cost-effectiveness is unknown. METHODS: A cost-utility model was developed to assess the incremental cost-effectiveness ratio (ICER) of recommended screening strategies for patients with clinically suspected MASLD, specifically those with type 2 diabetes (T2D) and obesity with multiple cardiometabolic risk factors which will be initiated in primary care. Six screening strategies were assessed, using either vibration-controlled transient elastography (VCTE) or the enhanced liver fibrosis (ELF) test as a second-line test following an initial Fibrosis-4 (FIB-4) assessment as the first line NIT. The model included treatment effects of resmetirom for metabolic dysfunction-associated steatohepatitis (MASH) patients with F2 or F3 fibrosis. RESULTS: All screening strategies for high-risk MASLD in US incurred additional costs compared to no screening, ranging from $13 587 to $14 730 per patient with T2D and $14 274 to $15 661 per patient with obesity. However, screening reduced long-term costs, ranging from $22 150 to $22 279 per patient with T2D and $13 704 to $13 705 per patient with obesity, compared to $24 221 and $14 956 for no screening, respectively. ICERs ranged from $26 913 to $27 884 per QALY for T2D patients and $23 265 to $24 992 per QALY for patients with obesity. While ICERs were influenced by VCTE availability, they remained cost-effective when using ELF as the second-line test. Our findings remain robust across a range of key parameters. CONCLUSIONS: Screening for high-risk MASLD is cost-effective according to recent guidelines. Implementing these screening strategies in primary care should be considered.

Concordance between metabolic dysfunction-associated steatotic liver disease and nonalcoholic fatty liver disease.

AIM: A multisociety consensus group proposed a new nomenclature for metabolic dysfunction-associated steatotic liver disease (MASLD). Although patients with nonalcoholic fatty liver disease (NAFLD) are expected to be reclassified as patients with MASLD under the new nomenclature, the concordance between MASLD and NAFLD remains unclear. Moreover, waist circumference could be adjusted by ethnicity for diagnosing MASLD; however, there are limited data on the optimal waist circumference in the Japanese population. METHODS: This cross-sectional study was conducted on 3709 Japanese patients with NAFLD. The primary endpoint was the prevalence of MASLD in patients with NAFLD. The difference between the original waist circumference criteria (>94 cm for men and >80 cm for women) and the Japanese metabolic syndrome criteria (≥85 cm for men and ≥90 cm for women) for concordance between NAFLD and MASLD was also investigated. RESULTS: According to the original criteria, the prevalence of MASLD in patients with NAFLD was 96.7%. Similarly, according to the Japanese waist circumference criteria, 96.2% of patients with NAFLD could be reclassified as those with MASLD. The concordance rate was significantly higher in the original criteria than in the Japanese criteria (p = 0.02). CONCLUSIONS: NAFLD could be considered MASLD using the original MASLD criteria in the Japanese population, and insights from NAFLD research could be applied to MASLD.

Fibrosis and steatotic liver disease in US adolescents according to the new nomenclature.

OBJECTIVE: To apply the new nomenclature for steatotic liver diseases (SLD), replacing nonalcoholic fatty liver disease (NAFLD) with metabolic dysfunction-associated steatotic liver disease (MASLD), in adolescents using National Health and Nutrition Examination Survey (NHANES) data. METHODS: Among 1410 adolescents (12-19 years) in NHANES (2017-March, 2020), the controlled attenuation parameter (CAP) of transient elastography (TE) was used to define steatosis and fibrosis (TE ≥ 7.4 kPa). Obesity and alanine aminotransferase (ALT) ≥ 80 U/L were used to identify adolescents qualifying for hepatology referral according to practice guidelines. NAFLD was defined as liver steatosis without a specific exposure; it has no cardiometabolic risk factor requirement, unlike MASLD. RESULTS: Steatosis (yes/no) is the first decision point in the new diagnostic protocol; however, criteria for steatosis are undefined. At the supplier (EchoSens)-recommended CAP threshold of 240 dB/m, 30.5% (95% confidence interval [CI]: 27.1%-34.0%) of adolescents had SLD and about 85% of adolescents with NAFLD met criteria for MASLD. The other 15% would receive an ambiguous diagnosis of either cryptogenic SLD or possible MASLD. At higher CAP thresholds, MASLD/NAFLD concordance increased and approached 100%. Among adolescents with MASLD-fibrosis, only 8.8% (95% CI: 0%-19.3%) had overweight/obese and ALT ≥ 80 U/L. CONCLUSIONS: The new nomenclature highlights the high prevalence of liver steatosis. At the CAP threshold of 240 dB/m, however, approximately 15% of adolescents would receive an ambiguous diagnosis, which could lead to confusion and worry. Fewer than 10% of adolescents with MASLD-fibrosis had overweight/obese and ALT ≥ 80 U/L. Revised guidelines are needed to ensure that the other 90% receive appropriate referral and liver disease care.

Therapeutic opportunities for the treatment of NASH with genetically validated targets.

The identification of genetic variants associated with fatty liver disease (FLD) from genome-wide association studies started in 2008 when single nucleotide polymorphisms in PNPLA3, the gene encoding patatin-like phospholipase domain-containing 3, were found to be associated with altered hepatic fat content. Since then, several genetic variants associated with protection from, or an increased risk of, FLD have been identified. The identification of these variants has provided insight into the metabolic pathways that cause FLD and enabled the identification of potential therapeutic targets. In this mini-review, we will examine the therapeutic opportunities derived from genetically validated targets in FLD, including oligonucleotide-based therapies targeting PNPLA3 and HSD17B13 that are currently being evaluated in clinical trials for the treatment of NASH (non-alcoholic steatohepatitis).

MBOAT7 in liver and extrahepatic diseases.

MBOAT7 is a protein anchored to endomembranes by several transmembrane domains. It has a catalytic dyad involved in remodelling of phosphatidylinositol with polyunsaturated fatty acids. Genetic variants in the MBOAT7 gene have been associated with the entire spectrum of non-alcoholic fatty liver (NAFLD), recently redefined as metabolic dysfunction-associated fatty liver disease (MAFLD) and, lately, steatotic liver disease (SLD), and to an increasing number of extrahepatic conditions. In this review, we will (a) elucidate the molecular mechanisms by which MBOAT7 loss-of-function predisposes to MAFLD and neurodevelopmental disorders and (b) discuss the growing number of genetic studies linking MBOAT7 to hepatic and extrahepatic diseases. MBOAT7 complete loss of function causes severe changes in brain development resulting in several neurological manifestations. Lower MBOAT7 hepatic expression at both the mRNA and protein levels, due to missense nucleotide polymorphisms (SNPs) in the locus containing the MBOAT7 gene, affects specifically metabolic and viral diseases in the liver from simple steatosis to hepatocellular carcinoma, and potentially COVID-19 disease. This body of evidence shows that phosphatidylinositol remodelling is a key factor for human health.

Real-Time Compensation for SLD Light-Power Fluctuation in an Interferometric Fiber-Optic Gyroscope.

An interferometric fiber-optic gyroscope (IFOG) demodulates a rotation signal via interferometric light intensity. However, the working environments of IFOGs typically involve great uncertainty. Fluctuations in temperature, air pressure, electromagnetic field, and the power system all cause the power of the superluminescent diode (SLD) light source to fluctuate as well. In this invited paper, we studied the effects of SLD power fluctuation on the dynamic and static performance characteristics of a gyro system through the use of a light-power feedback loop. Fluctuations of 0.5 mA, 1 mA, and 5 mA in the SLD source entering the IFOG caused zero-bias stability to be 69, 135, and 679 times worse. We established an effective method to monitor power fluctuations of SLD light sources and to compensate for their effects without increasing hardware complexity or system cost. In brief, we established a real-time power-sensing and -compensating system. Experimental results showed that for every 0.1 mA increase in the fluctuation amplitude of the driving current, the zero-bias stability became 4 to 7 times worse, which could be reduced about 95% through the use of SLD power compensation.

Specific Learning Disorders: Variation Analysis of 15 Candidate Genes in 9 Multiplex Families.

Background and Objectives: Specific Learning Disorder (SLD) is a complex neurobiological disorder characterized by a persistent difficult in reading (dyslexia), written expression (dysgraphia), and mathematics (dyscalculia). The hereditary and genetic component is one of the underlying causes of SLD, but the relationship between genes and the environment should be considered. Several genetic studies were performed in different populations to identify causative genes. Materials and Methods: Here, we show the analysis of 9 multiplex families with at least 2 individuals diagnosed with SLD per family, with a total of 37 persons, 21 of whom are young subjects with SLD, by means of Next-Generation Sequencing (NGS) to identify possible causative mutations in a panel of 15 candidate genes: CCPG1, CYP19A1, DCDC2, DGKI, DIP2A, DYM, GCFC2, KIAA0319, MC5R, MRPL19, NEDD4L, PCNT, PRMT2, ROBO1, and S100B. Results: We detected, in eight families out nine, SNP variants in the DGKI, DIP2A, KIAA0319, and PCNT genes, even if in silico analysis did not show any causative effect on this behavioral condition. In all cases, the mutation was transmitted by one of the two parents, thus excluding the case of de novo mutation. Moreover, the parent carrying the allelic variant transmitted to the children, in six out of seven families, reports language difficulties. Conclusions: Although the present results cannot be considered conclusive due to the limited sample size, the identification of genetic variants in the above genes can provide input for further research on the same, as well as on other genes/mutations, to better understand the genetic basis of this disorder, and from this perspective, to better understand also the neuropsychological and social aspects connected to this disorder, which affects an increasing number of young people.

Extreme Polygenicity of Complex Traits Is Explained by Negative Selection.

Complex traits and common diseases are extremely polygenic, their heritability spread across thousands of loci. One possible explanation is that thousands of genes and loci have similarly important biological effects when mutated. However, we hypothesize that for most complex traits, relatively few genes and loci are critical, and negative selection-purging large-effect mutations in these regions-leaves behind common-variant associations in thousands of less critical regions instead. We refer to this phenomenon as flattening. To quantify its effects, we introduce a mathematical definition of polygenicity, the effective number of independently associated SNPs (Me), which describes how evenly the heritability of a trait is spread across the genome. We developed a method, stratified LD fourth moments regression (S-LD4M), to estimate Me, validating that it produces robust estimates in simulations. Analyzing 33 complex traits (average N = 361k), we determined that heritability is spread ∼4× more evenly among common SNPs than among low-frequency SNPs. This difference, together with evolutionary modeling of new mutations, suggests that complex traits would be orders of magnitude less polygenic if not for the influence of negative selection. We also determined that heritability is spread more evenly within functionally important regions in proportion to their heritability enrichment; functionally important regions do not harbor common SNPs with greatly increased causal effect sizes, due to selective constraint. Our results suggest that for most complex traits, the genes and loci with the most critical biological effects often differ from those with the strongest common-variant associations.

Children's vocabulary and friendships: A comparative study between children with and without Specific Learning Disorder and Attention Deficit Hyperactivity Disorder.

Language skills are important in the formation and maintenance of friendships. Children with specific learning disorder (SLD) or attention-deficit/hyperactivity disorder (ADHD) experience difficulties with their relationships and have language-related problems. This study aims to examine how expressive and receptive vocabulary may relate to friendships of children with and without SLD or ADHD. Participants were 64 children with SLD, 64 children with ADHD, and 64 typically developing (TD) children, aged 8-12 years (Mage  = 9.77 years, SD = 1.22), attending Grades 3 to 6 in inclusive primary schools of Attica, Greece. The Greek versions of the Peabody Picture Vocabulary Test and the expressive vocabulary subscale of the WISC-III were administered along with the sociometric nominations of friends and the self-reports of best friendship duration. Results showed that children with SLD and ADHD reported best friendships of shorter duration and had significantly poorer receptive and expressive vocabulary. Children with ADHD had significantly fewer close and best friends than children with SLD, who in turn had significantly fewer close and best friends than the TD children. Children's vocabulary in all three groups was positively correlated with the duration of their best friendships and was found to moderately predict children's close friendships.

The CRK2-CYC13 complex functions as an S-phase cyclin-dependent kinase to promote DNA replication in Trypanosoma brucei.

BACKGROUND: Faithful DNA replication is essential to maintain genomic stability in all living organisms, and the regulatory pathway for DNA replication initiation is conserved from yeast to humans. The evolutionarily ancient human parasite Trypanosoma brucei, however, lacks many of the conserved DNA replication factors and may employ unusual mechanisms for DNA replication. Neither the S-phase cyclin-dependent kinase (CDK) nor the regulatory pathway governing DNA replication has been previously identified in T. brucei. RESULTS: Here we report that CRK2 (Cdc2-related kinase 2) complexes with CYC13 (Cyclin13) and functions as an S-phase CDK to promote DNA replication in T. brucei. We further show that CRK2 phosphorylates Mcm3, a subunit of the Mcm2-7 sub-complex of the Cdc45-Mcm2-7-GINS complex, and demonstrate that Mcm3 phosphorylation by CRK2 facilitates interaction with Sld5, a subunit of the GINS sub-complex of the Cdc45-Mcm2-7-GINS complex. CONCLUSIONS: These results identify the CRK2-CYC13 complex as an S-phase regulator in T. brucei and reveal its role in regulating DNA replication through promoting the assembly of the Cdc45-Mcm2-7-GINS complex.

Predictors of adverse maternal outcome in jaundiced pregnant women identified as having pregnancy-specific liver disease (P-sLD).

We aimed to study the factors including model for end stage liver disease (MELD) score in predicting mortality in women with pregnancy-specific liver diseases (P-sLD). A total of 154 women with clinical jaundice were studied of which 138 women were diagnosed with P-sLD. The most common P-sLD was HELLP syndrome (51.9%) followed by acute fatty liver of pregnancy (AFLP) (17.5%). The mean age was 26.3 ± 4.7 years and the mean gestational age was 35.1 ± 4.2 weeks. The maternal death rate was 26.8% and the most common cause was coagulopathy followed by sepsis. The mean MELD score among non survivors was 25.98 ± 8.17 compared to 17.29 ± 8.12 among survivors (p value .00). On univariate analysis, gestational age at admission, presence of hypertension, the platelet count, serum creatinine, INR and MELD score were found to significant. The AUC for INR (0.82) and MELD score (0.77) was better than platelet count (0.72) and serum creatinine (0.67). On multivariate analysis, only the INR and presence of AKI were found to be significantly associated with maternal mortality. The performance of INR was better than MELD score in predicting mortality in women with P-sLD. Additional factors like platelet count may be incorporated in to MELD score for the prediction of mortality in pregnant women.IMPACT STATEMENTWhat is already known on this subject? Pregnancy-specific liver disorders (P-sLD) have significant effect on maternal and foetal outcome, often considered as a spectrum of disease with significant overlap of clinical and laboratory parameters. MELD score is used reliably outside the pregnancy to predict mortality may not be good in pregnant women. There are only few studies that looked at the factors predictive of adverse maternal outcome.What do the results of this study add? Though we have demonstrated that MELD score was significantly high among non-survivors, serum bilirubin an important component of MELD score was not found to be significant. The other factors which were found to be significant on univariate analysis include gestational age at admission, hypertension and platelet count. However, international normalised ratio (INR) and acute kidney injury (AKI) were the factors independently associated with mortality.What are the implications for clinical practice and/or further research? The utility of MELD score in P-sLD should be studied prospectively in different populations. Moreover, the feasibility of developing a simple model which incorporates platelet count in addition to other components of MELD score should also be explored in future studies.

Multiple RNA virus matrix proteins interact with SLD5 to manipulate host cell cycle.

The matrix protein of many enveloped RNA viruses regulates multiple stages of viral life cycle and has the characteristics of nucleocytoplasmic shuttling. We have previously demonstrated that matrix protein 1 (M1) of an RNA virus, influenza virus, blocks host cell cycle progression by interacting with SLD5, a member of the GINS complex, which is required for normal cell cycle progression. In this study, we found that M protein of several other RNA viruses, including VSV, SeV and HIV, interacted with SLD5. Furthermore, VSV/SeV infection and M protein of VSV/SeV/HIV induced cell cycle arrest at G0/G1 phase. Importantly, overexpression of SLD5 partially rescued the cell cycle arrest by VSV/SeV infection and VSV M protein. In addition, SLD5 suppressed VSV replication in vitro and in vivo, and enhanced type Ⅰ interferon signalling. Taken together, our results suggest that targeting SLD5 by M protein might be a common strategy used by multiple enveloped RNA viruses to block host cell cycle. Our findings provide new mechanistic insights for virus to manipulate cell cycle progression by hijacking host replication factor SLD5 during infection.

Histones on fire: the effect of Dun1 and Mrc1 on origin firing and replication of hyper-acetylated genomes.

As cells replicate their DNA, there is a need to synthesize new histones with which to wrap it. Newly synthesized H3 histones that are incorporated into the assembling chromatin behind the replication fork are acetylated at lysine 56. The acetylation is removed by two deacetylases, Hst3 and Hst4. This process is tightly regulated and any perturbation leads to genomic instability and replicative stress. We recently showed that Dun1, a kinase implicated mainly in the regulation of dNTPs, is vital in cells with hyper-acetylation, to counteract Rad53's inhibition on late-firing origins of replication. Our work showed that ∆hst3 ∆hst4 cells depend on late origin firing for survival, and are unable to prevent Rad53's inhibition when Dun1 is inactive. Thus, our work describes a role for Dun1 that is independent on its known function as a regulator of dNTP levels. Here we show that Mrc1 (Claspin in mammals), a protein that moves with the replicating fork and participates in both replication and checkpoint functions, plays also an essential role in the absence of H3K56Ac deacetylation. The sum of the results shown here and in our recent publication suggests that dormant origins are also utilized in these cells, making Mrc1, which regulates firing from these origins, also essential when histone H3 is hyper-acetylated. Thus, cells suffering from hyper-acetylation of H3K56 experience replication stress caused by a combination of prone-to-collapse forks and limited replication tracts. This combination makes both Dun1 and Mrc1, each acting on different targets, essential for viability.

Icing Condition Predictions Using FBGS.

Icing is a hazard which is important for the aerospace industry and which has grown over the last few years. Developing sensors that can detect the existence not only of standard icing conditions with typically small droplet size, but also of Supercooled Large Droplet (SLD) conditions is one of the most important aims in order to minimize icing hazards in the near future. In the present paper a study of the Fiber Bragg Grating Sensors' (FBGSs) performance as a flight icing detection system that predicts the conditions of an icing cloud is carried out. The test matrix was performed in the INTA Icing Wind Tunnel (IWT) with several icing conditions including SLD. Two optic fibers with 16 FBGS in total were integrated in the lower and upper surface of an airfoil to measure the temperature all over the chord. The results are compared with a Messinger heat and mass balance model and the measurements of the FBGS are used to predict the Liquid Water Content (LWC) and Ice Accretion Rate (IAR). Finally, the results are evaluated and a sensor assessment is made. A good correlation was observed between theoretical calculations and test results obtained with the FBGS in the IWT tests. FBGS proved to detect the beginning and end of ice accretion, LWC and IAR quickly and with good precision.

Phosphopeptide binding by Sld3 links Dbf4-dependent kinase to MCM replicative helicase activation.

The initiation of eukaryotic DNA replication requires the assembly of active CMG (Cdc45-MCM-GINS) helicases at replication origins by a set of conserved and essential firing factors. This process is controlled during the cell cycle by cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), and in response to DNA damage by the checkpoint kinase Rad53/Chk1. Here we show that Sld3, previously shown to be an essential CDK and Rad53 substrate, is recruited to the inactive MCM double hexamer in a DDK-dependent manner. Sld3 binds specifically to DDK-phosphorylated peptides from two MCM subunits (Mcm4, 6) and then recruits Cdc45. MCM mutants that cannot bind Sld3 or Sld3 mutants that cannot bind phospho-MCM or Cdc45 do not support replication. Moreover, phosphomimicking mutants in Mcm4 and Mcm6 bind Sld3 without DDK and facilitate DDK-independent replication. Thus, Sld3 is an essential "reader" of DDK phosphorylation, integrating signals from three distinct protein kinase pathways to coordinate DNA replication during S phase.

Influenza virus matrix protein M1 interacts with SLD5 to block host cell cycle.

Influenza virus matrix 1 protein (M1) is highly conserved and plays essential roles at many stages of virus life cycle. Here, we used a yeast two-hybrid system to identify the host protein SLD5, a component of the GINS complex, which is essential for the initiation of DNA replication in eukaryotic cells, as a new M1 interacting protein. M1 from several different influenza virus strains all interacted with SLD5. Overexpression of SLD5 suppressed influenza virus replication. Transient, stable, or inducible expression of M1 induced host cell cycle blockade at G0/G1 phase. Moreover, SLD5 partially rescued M1 expression- or influenza virus infection-induced G0/G1 phase accumulation in cell lines and primary mouse embryonic fibroblasts. Importantly, SLD5 transgenic mice exhibited higher resistance and improved lung epithelial regeneration after virus infection compared with wild-type mice. Therefore, influenza virus M1 blocks host cell cycle process by interacting with SLD5. Our finding reveals the multifunctional nature of M1 and provides new insight for understanding influenza virus-host interaction.