H3 K27M and EZHIP Impede H3K27-Methylation Spreading by Inhibiting Allosterically Stimulated PRC2.

Diffuse midline gliomas and posterior fossa type A ependymomas contain the recurrent histone H3 lysine 27 (H3 K27M) mutation and express the H3 K27M-mimic EZHIP (CXorf67), respectively. H3 K27M and EZHIP are competitive inhibitors of Polycomb Repressive Complex 2 (PRC2) lysine methyltransferase activity. In vivo, these proteins reduce overall H3 lysine 27 trimethylation (H3K27me3) levels; however, residual peaks of H3K27me3 remain at CpG islands (CGIs) through an unknown mechanism. Here, we report that EZHIP and H3 K27M preferentially interact with PRC2 that is allosterically activated by H3K27me3 at CGIs and impede its spreading. Moreover, H3 K27M oncohistones reduce H3K27me3 in trans, independent of their incorporation into the chromatin. Although EZHIP is not found outside placental mammals, expression of human EZHIP reduces H3K27me3 in Drosophila melanogaster through a conserved mechanism. Our results provide mechanistic insights for the retention of residual H3K27me3 in tumors driven by H3 K27M and EZHIP.

Both middle and large envelope proteins can mediate neutralization of hepatitis B virus infectivity by anti-preS2 antibodies: escape by naturally occurring preS2 deletions.

Hepatitis B virus (HBV) expresses co-terminal large (L), middle (M), and small (S) envelope proteins containing preS1/preS2/S, preS2/S, and S domain alone, respectively. S and preS1 domains mediate sequential virion attachment to heparan sulfate proteoglycans and sodium taurocholate cotransporting polypeptide (NTCP), respectively, which can be blocked by anti-S and anti-preS1 antibodies. How anti-preS2 antibodies neutralize HBV infectivity remains enigmatic. The late stage of chronic HBV infection often selects for mutated preS2 translation initiation codon to prevent M protein expression, or in-frame preS2 deletions to shorten both L and M proteins. When introduced to infectious clone of genotype C or D, both M-minus mutations and most 5' preS2 deletions sustained virion production. Such mutant progeny viral particles were infectious in NTCP-reconstituted HepG2 cells. Neutralization experiments were performed on the genotype D clone. Although remaining susceptible to anti-preS1 and anti-S neutralizing antibodies, M-minus mutants were only partially neutralized by two anti-preS2 antibodies tested while preS2 deletion mutants were resistant. By infection experiments using viral particles with lost versus increased M protein expression, or a neutralization escaping preS2 deletion only present on L or M protein, we found that both full-length L and M proteins contributed to virus neutralization by the two anti-preS2 antibodies. Thus, immune escape could be a driving force for the selection of M-minus mutations, and especially preS2 deletions. The fact that both L and M proteins could mediate neutralization by anti-preS2 antibodies may shed light on the underlying molecular mechanism.IMPORTANCEThe large (L), middle (M), and small (S) envelope proteins of hepatitis B virus (HBV) contain preS1/preS2/S, preS2/S, and S domain alone, respectively. The discovery of heparan sulfate proteoglycans and sodium taurocholate cotransporting polypeptide (NTCP) as the low- and high-affinity HBV receptors could explain neutralizing potential of anti-S and anti-preS1 antibodies, respectively, but how anti-preS2 neutralizing antibodies work remains enigmatic. In this study, we found two M-minus mutants in the context of genotype D partially escaped two anti-preS2 neutralizing antibodies in NTCP-reconstituted HepG2 cells, while several naturally occurring preS2 deletion mutants escaped both antibodies. By point mutations to eliminate or enhance M protein expression, and by introducing preS2 deletion selectively to L or M protein, we found binding of anti-preS2 antibodies to both L and M proteins contributed to neutralization of wild-type HBV infectivity. Our finding may shed light on the possible mechanism(s) whereby anti-preS2 antibodies neutralize HBV infectivity.

Multitasking by Polycomb response elements.

Development requires the expression of master regulatory genes necessary to specify a cell lineage. Equally significant is the stable and heritable silencing of master regulators that would specify alternative lineages. This regulated gene silencing is carried out by Polycomb group (PcG) proteins, which must be correctly recruited only to the subset of their target loci that requires lineage-specific silencing. A recent study by Erceg and colleagues (pp. 590-602) expands on a key aspect of that targeting: The same DNA elements that recruit PcG complexes to a repressed locus also encode transcriptional enhancers that function in different lineages where that locus must be expressed. Thus, PcG targeting elements overlap with enhancers.

Dual functionality of cis-regulatory elements as developmental enhancers and Polycomb response elements.

Developmental gene expression is tightly regulated through enhancer elements, which initiate dynamic spatio-temporal expression, and Polycomb response elements (PREs), which maintain stable gene silencing. These two cis-regulatory functions are thought to operate through distinct dedicated elements. By examining the occupancy of the Drosophila pleiohomeotic repressive complex (PhoRC) during embryogenesis, we revealed extensive co-occupancy at developmental enhancers. Using an established in vivo assay for PRE activity, we demonstrated that a subset of characterized developmental enhancers can function as PREs, silencing transcription in a Polycomb-dependent manner. Conversely, some classic Drosophila PREs can function as developmental enhancers in vivo, activating spatio-temporal expression. This study therefore uncovers elements with dual function: activating transcription in some cells (enhancers) while stably maintaining transcriptional silencing in others (PREs). Given that enhancers initiate spatio-temporal gene expression, reuse of the same elements by the Polycomb group (PcG) system may help fine-tune gene expression and ensure the timely maintenance of cell identities.

Neuropilin-1 is a novel host factor modulating the entry of hepatitis B virus.

BACKGROUND & AIMS: Sodium taurocholate cotransporting polypeptide (NTCP) has been identified as the cellular receptor for HBV. However, hepatocytes expressing NTCP exhibit varying susceptibilities to HBV infection. This study aimed to investigate whether other host factors modulate the process of HBV infection. METHODS: Liver biopsy samples obtained from children with hepatitis B were used for single-cell sequencing and susceptibility analysis. Primary human hepatocytes, HepG2-NTCP cells, and human liver chimeric mice were used to analyze the effect of candidate host factors on HBV infection. RESULTS: Single-cell sequencing and susceptibility analysis revealed a positive correlation between neuropilin-1 (NRP1) expression and HBV infection. In the HBV-infected cell model, NRP1 overexpression before HBV inoculation significantly enhanced viral attachment and internalization, and promoted viral infection in the presence of NTCP. Mechanistic studies indicated that NRP1 formed a complex with LHBs (large hepatitis B surface proteins) and NTCP. The NRP1 b domain mediated its interaction with conserved arginine residues at positions 88 and 92 in the preS1 domain of LHBs. This NRP1-preS1 interaction subsequently promoted the binding of preS1 to NTCP, facilitating viral infection. Moreover, disruption of the NRP1-preS1 interaction by the NRP1 antagonist EG00229 significantly attenuated the binding affinity between NTCP and preS1, thereby inhibiting HBV infection both in vitro and in vivo. CONCLUSIONS: Our findings indicate that NRP1 is a novel host factor for HBV infection, which interacts with preS1 and NTCP to modulate HBV entry into hepatocytes. IMPACT AND IMPLICATIONS: HBV infection is a global public health problem, but the understanding of the early infection process of HBV remains limited. Through single-cell sequencing, we identified a novel host factor, NRP1, which modulates HBV entry by interacting with HBV preS1 and NTCP. Moreover, antagonists targeting NRP1 can inhibit HBV infection both in vitro and in vivo. This study could further advance our comprehension of the early infection process of HBV.

Characterization of integrated hepatitis B virus DNA harboring pre-S mutations in hepatocellular carcinoma patients with ground glass hepatocytes.

Ground glass hepatocytes (GGHs) have been associated with hepatocellular carcinoma (HCC) recurrence and poor prognosis. We previously demonstrated that pre-S expression in some GGHs is resistant to current hepatitis B virus (HBV) antiviral therapies. This study aimed to investigate whether integrated HBV DNA (iDNA) is the primary HBV DNA species responsible for sustained pre-S expression in GGH after effective antiviral therapy. We characterized 10 sets of micro-dissected, formalin-fixed-paraffin-embedded, and frozen GGH, HCC, and adjacent hepatitis B surface antigen-negative stained tissues for iDNA, pre-S deletions, and the quantity of covalently closed circular DNA. Eight patients had detectable pre-S deletions, and nine had detectable iDNA. Interestingly, eight patients had integrations within the TERT and CCNE1 genes, which are known recurrent integration sites associated with HCC. Furthermore, we observed a recurrent integration in the ABCC13 gene. Additionally, we identified variations in the type and quantity of pre-S deletions within individual sets of tissues by junction-specific PacBio long-read sequencing. The data from long-read sequencing indicate that some pre-S deletions were acquired following the integration events. Our findings demonstrate that iDNA exists in GGH and can be responsible for sustained pre-S expression in GGH after effective antiviral therapy.

Frequency of ischaemic stroke and intracranial haemorrhage in patients with reversible cerebral vasoconstriction syndrome (RCVS) and posterior reversible encephalopathy syndrome (PRES) - A systematic review.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) may cause ischaemic stroke and intracranial haemorrhage. The aim of our study was to assess the frequency of the afore-mentioned outcomes. METHODS: We performed a PROSPERO-registered (CRD42022355704) systematic review and meta-analysis accessing PubMed until 7 November 2022. The inclusion criteria were: (1) original publication, (2) adult patients (≥18 years), (3) enrolling patients with PRES and/or RCVS, (4) English language and (5) outcome information. Outcomes were frequency of (1) ischaemic stroke and (2) intracranial haemorrhage, divided into subarachnoid haemorrhage (SAH) and intraparenchymal haemorrhage (IPH). The Cochrane Risk of Bias tool was used. RESULTS: We identified 848 studies and included 48 relevant studies after reviewing titles, abstracts and full text. We found 11 studies on RCVS (unselected patients), reporting on 2746 patients. Among the patients analysed, 15.9% (95% CI 9.6%-23.4%) had ischaemic stroke and 22.1% (95% CI 10%-39.6%) had intracranial haemorrhage. A further 20.3% (95% CI 11.2%-31.2%) had SAH and 6.7% (95% CI 3.6%-10.7%) had IPH. Furthermore, we found 28 studies on PRES (unselected patients), reporting on 1385 patients. Among the patients analysed, 11.2% (95% CI 7.9%-15%) had ischaemic stroke and 16.1% (95% CI 12.3%-20.3%) had intracranial haemorrhage. Further, 7% (95% CI 4.7%-9.9%) had SAH and 9.7% (95% CI 5.4%-15%) had IPH. CONCLUSIONS: Intracranial haemorrhage and ischaemic stroke are common outcomes in PRES and RCVS. The frequency reported in the individual studies varied considerably.

Posterior Reversible Encephalopathy Syndrome in Children and Adolescents.

PURPOSE OF REVIEW: Posterior reversible encephalopathy syndrome, or PRES, is a constellation of severe, acute hypertension and specific brain imaging findings. This may be caused by failure of the cerebral autoregulatory system to manage acute or severe changes in blood pressure. The incidence in children is unknown but estimated to be more common in children with predisposing factors including renal disease, autoimmune disease, malignancy, solid organ transplantation, stem cell transplantation, hypertension, sepsis, and exposure to certain medications. RECENT FINDINGS: Management of PRES includes addressing hypertension, removing offending agents when possible, and anti-epileptic medications. Most children with PRES recover completely, but recurrence is possible. Lack of resolution of imaging findings likely portends a worse prognosis.

Lithium-induced subacute diencephalic angio endotheliopathy.

A 65-years-old woman with bipolar affective disorder presented to our ED with a severe lithium intoxication and the recent onset of confusion, clumsiness, and tremors. Symptoms worsened to stupor and anarthria immediately after hospital admission. Gadolinium-enhanced brain Magnetic Resonance Imaging (MRI) showed signal hyperintensity involving both thalami in T2weighted (T2w)/Fluid Attenuated Inversion Recovery sequences (right > left), restricted areas of proton diffusivity at the level of both occipital lobes and a sharp contrast enhancement of thalami, rhombencephalon, and of leptomeninges from either the temporal, parietal, occipital lobes as well as from the cerebellar folia (right > left). These findings were consistent with a severe form of Posterior Encephalopathy known as Subacute Diencephalic Angio Endotheliopahty (SDAE). In addition, Magnetic Resonance Angiography revealed thrombosis of the right transverse and sigmoidal sinuses up to confluence with the jugular vein. The MRI picture resolved one month later after a course of high dosage dexamethasone. The patient deceased one month after discharge, mainly due to Diabetes Insipidusassociated hypernatremia. Dissecting the "Pandora's box" represented by complex MRI findings (SDAE and sinus thrombosis) in lithium-induced neurotoxicity is fundamental in timely recognizing this threating but potentially reversible clinical picture.

Tacrolimus-associated neurotoxicity isolated to the brainstem: two illustrative cases and a systematic review of the literature.

INTRODUCTION: Tacrolimus-associated neurotoxicity (TAN) manifests with wide clinical spectrum, ranging from mild tremors to severe encephalopathy. The isolated involvement of the brainstem is a rarely documented presentation of TAN, and its clinical and diagnostic characteristics are unclear. METHODS: We report two cases of brainstem-isolated TAN (bi-TAN). Moreover, we performed a systematic review of the literature on bi-TAN and extracted data concerning demographics, clinical characteristics, radiological features, and management. The systematic literature search followed PRISMA guidelines and a pre-defined protocol. RESULTS: Eleven patients, including our two, were identified (mean age: 41.3 years, ± 18.8; five males, 45%). Speech disturbance was the most common clinical presentation (45%). The mean latency from Tacrolimus initiation to bi-TAN onset was 26 days (± 30.8). Tacrolimus serum level tested above the reference range in three patients (mean: 26.83 ± 5.48). Brain MRI showed T2-FLAIR hyperintensities; three showed restricted diffusion on ADC maps. Neurological symptoms resolved completely in seven patients (63%) after Tacrolimus withdrawal or dose reduction. CONCLUSIONS: Our findings suggest that bi-TAN could represent a brainstem variant of posterior reversible encephalopathy syndrome. Recognition of bi-TAN as a potential cause of isolated brainstem lesions is crucial to disentangle the diagnostic work-up and ensure prompt withdrawal or reduction of the offending agent.

Posterior reversible encephalopathy syndrome and acute ischemic stroke: an underreported association.

INTRODUCTION: Posterior reversible encephalopathy syndrome (PRES) is a rare and complex disorder with variable clinical presentation and a typical magnetic resonance imaging (MRI) pattern of vasogenic edema with typical and atypical locations. It is often triggered by other diseases and drugs and the most prototypical association is with persistently elevated arterial pressure values. Among the potential cerebrovascular complications, intracranial bleeding has been described, but ischemic stroke is uncommonly reported. METHODS: We are presenting a case of a male patient with prolonged and sustained arterial hypertension acutely presenting with lacunar ischemic stroke involving the right corona radiata and composite MRI findings with the association of chronic small vessel disease (SVD) markers, acute symptomatic lacunar stroke, and atypical, central variant, posterior fossa dominant PRES. In the MRI follow-up, the white matter hyperintensities in T2-fluid attenuated inversion recovery (FLAIR sequences) due to PRES. DISCUSSION: The pathophysiology of PRES is not yet fully known, but the association with markedly increased values of arterial pressure is typical. In this context, ischemic stroke has not been considered in the clinical and neuroradiological manifestations of PRES and it has been only occasionally reported in the literature. In this case, the main hypothesis is that sustained hypertension may have triggered both manifestations, PRES, and ischemic stroke and the last one allowed to diagnose the first one. CONCLUSIONS: Atypical variants of PRES are not so rare and it may also occur in typical triggering situations. The association with ischemic stroke is even rarer and it may add some clues to the pathomechanisms of PRES.

Posterior reversible encephalopathy syndrome associated with antibiotic therapy: a case report and systematic review.

Posterior reversible encephalopathy syndrome (PRES) is an acute neurological condition associated with different etiologies, including antibiotic therapy. To date, most data regarding antibiotic-related PRES are limited to case reports and small case series. Here, we report a novel case description and provide a systematic review of the clinico-radiological characteristics and prognosis of available cases of PRES associated with antibiotic therapy. We performed a systematic literature search in PubMed and Scopus from inception to 10 January 2024, following PRISMA guidelines and a predefined protocol. The database search yielded 12 subjects (including our case). We described the case of a 55-year-old female patient with PRES occurring one day after administration of metronidazole and showing elevated serum neurofilament light chain protein levels and favorable outcome. In our systematic review, antibiotic-associated PRES was more frequent in female patients (83.3%). Metronidazole and fluoroquinolones were the most reported antibiotics (33.3% each). Clinical and radiological features were comparable to those of PRES due to other causes. Regarding the prognosis, about one third of the cases were admitted to the intensive care unit, but almost all subjects (90.0%) had a complete or almost complete clinical and radiological recovery after prompt cessation of the causative drug. Antibiotic-associated PRES appears to share most of the characteristics of classic PRES. Given the overall good prognosis of the disease, it is important to promptly diagnose antibiotic-associated PRES and discontinue the causative drug.

Association between renal insufficiency and lesion characteristics of posterior reversible encephalopathy syndrome.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is characterized by cerebral blood flow dysregulation and the blood-brain barrier (BBB) disruption. While renal insufficiency has been considered a factor in BBB fragility, the relationship between renal insufficiency and the PRES lesions volume remains unclear. METHODS: This observational study was performed retrospectively. PRES patients were categorized into two groups with renal insufficiency, defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73m2 on the day of symptom occurrence. Lesion volume was measured using fluid-attenuated inversion recovery (FLAIR) imaging, and the brain was divided into nine regions. The volume of the parietal-occipital-temporal lobe was considered typical, while the other six regions were labeled as atypical. RESULTS: The study included 200 patients, of whom 94 (47%) had renal insufficiency. Patients with renal insufficiency had a larger lesion volume (144.7 ± 125.2 cc) compared to those without renal insufficiency (110.5 ± 93.2 cc; p = 0.032); particularly in the atypical lesions volume (49.2 ± 65.0 vs. 29.2 ± 44.3 cc; p = 0.013). However, there was no difference in the reversibility of the lesions (35.2 ± 67.5 vs. 18.8 ± 33.4 cc; p = 0.129). Multiple regression analysis revealed that decreases in eGFR (ß = -0.34, 95% CI -0.62-0.05, p = 0.020) were positively associated with total lesion volume. CONCLUSION: Our findings suggest that PRES patients with renal insufficiency experience more severe lesion volumes, likely due to the atypical brain regions involvement. The lesions involving atypical regions may have a similar pathophysiology to typical lesions, as the PRES lesions reversibility was found to be similar between individuals with and without renal insufficiency.

Case report: Blood-transfusion induced posterior reversible encephalopathy syndrome.

Posterior reversible encephalopathy syndrome (PRES) is an increasingly recognized clinical entity associated with a variety of medical conditions. It is commonly considered in the presentation of uncontrolled, severe hypertension. However, more recently, it has been described in the setting of blood transfusion, particularly in those with chronic anemia, even in the absence of severe hypertension. We describe a patient who presented to the emergency department 12 days after large blood transfusion for severe, chronic anemia with headache, vision loss, expressive aphasia and a change in mental status, with only mild blood pressure elevation, who was ultimately diagnosed with PRES and refractory non-convulsive status epilepticus. Emergency physicians are often the first to initiate blood transfusion for those with a low hemoglobin. Therefore, it is prudent to proceed with caution in transfusing those with chronic anemia. It is also important for the emergency physician to keep PRES on the differential for those presenting with a neurologic complaint after correction of their chronic anemia, even in the absence of severe hypertension.

Posterior reversible encephalopathy syndrome in the setting of IgA vasculitis.

IgA vasculitis (IgAV), formerly known as Henoch-Scholein purpura, is a small vessel vasculitis, most commonly seen in pediatric patients, that can affect numerous internal organs including the kidneys, lungs, gastrointestinal tract, and the central nervous system (CNS). CNS manifestations of this condition include hypertensive encephalopathy, thrombosis, optic neuropathy, seizures, CNS vasculitis, and a more recently described phenomenon known as posterior reversible encephalopathy syndrome (PRES). Symptoms of PRES include hypertension, altered mental status, and seizures caused by vasogenic disruption of the blood-brain barrier, and the condition is diagnosed by characteristic edema-related gray-white matter changes in the parieto-occipital lobes on magnetic resonance imaging. Herein, we present a rare case of PRES as a presenting sign of IgAV to increase awareness about this unusual association.

Genotyping Hepatitis B virus by Next-Generation Sequencing: Detection of Mixed Infections and Analysis of Sequence Conservation.

Our aim was to develop an accurate, highly sensitive method for HBV genotype determination and detection of genotype mixtures. We examined the preS and 5' end of the HBV X gene (5X) regions of the HBV genome using next-generation sequencing (NGS). The 1852 haplotypes obtained were subjected to genotyping via the Distance-Based discrimination method (DB Rule) using two sets of 95 reference sequences of genotypes A-H. In clinical samples from 125 patients, the main genotypes were A, D, F and H in Caucasian, B and C in Asian and A and E in Sub-Saharan patients. Genotype mixtures were identified in 28 (22.40%) cases, and potential intergenotypic recombination was observed in 29 (23.20%) cases. Furthermore, we evaluated sequence conservation among haplotypes classified into genotypes A, C, D, and E by computing the information content. The preS haplotypes exhibited limited shared conserved regions, whereas the 5X haplotypes revealed two groups of conserved regions across the genotypes assessed. In conclusion, we developed an NGS-based HBV genotyping method utilizing the DB Rule for genotype classification. We identified two regions conserved across different genotypes at 5X, offering promising targets for RNA interference-based antiviral therapies.

Impact of preS1 Evaluation in the Management of Chronic Hepatitis B Virus Infection.

Background and Objectives: The measurement of hepatitis B surface antigen (HBsAg) is essential for managing chronic hepatitis B virus infection (CHB). HBsAg consists of three different surface envelope proteins: large, middle, and small HB surface proteins. However, in clinical practice, it is not common to evaluate each of these HB surface proteins separately. Materials and Methods: In this study, we investigated preS1 expression using seven monoclonal antibodies (mAbs) in 68 CHB patients, as well as examining their antigenicity. Results: Although the seven mAbs had been derived from genotype (Gt) C, they could recognize preS1 with Gts A to D. The epitopes were concentrated within the aa33-47 region of preS1, and their antigenicity was significantly reduced by an aa45F substitution. We found that preS1 expression remained consistent regardless of HBsAg levels and different Gts in CHB patients, in contrast to what was observed in SHBs. Conclusions: These results suggest that the antigenic epitope is preserved among different Gts and that the expression pattern of preS1 is altered during CHB, highlighting its vital role in the HBV infection cycle. Our present results suggest preS1 is a promising therapeutic target in CHB.

Risk factors of posterior reversible encephalopathy syndrome in patients with preeclampsia or eclampsia: A retrospective review.

Background and purpose:

Posterior reversible encephalopathy syndrome (PRES) is characterized by vasogenic edema, usually reversible, with the prominent involvement of the parietal and occipital lobes. The exact etiopathogenesis leading to PRES is unknown. Because signs of eclampsia and preeclampsia in neuroimaging often overlap and manifest as PRES, we aimed to evaluate whether demographic, clinical, and laboratory parameters predict PRES in patients with preeclampsia or eclampsia.

213 pre-eclampsia or eclampsia patients with cranial imaging were retrospectively examined. We recorded the patients’ demographic information, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), hemogram, biochemical indicators, clinical symptoms, and imaging features.

Of all patients, 69% (n = 147) had preeclampsia while 31% (n = 66) had eclampsia, and 24.4% (n = 53) were diagnosed with PRES. The mean age of patients who developed PRES was 25.81 ± 6.07 years and thus significantly less than that of patients who did not develop PRES (p = .000). Patients with PRES had significantly higher mean SBP (p = .015), DBP (p = .009), and MAP (p = .003) than patients without PRES, along with significantly higher aspartate aminotransferase (ASAT; p = .001), alanine aminotransferase (ALAT; p = .001) blood urea nitrogen (BUN; p = .001), white blood cell (WBC; p = .003), neutrophil (p = .001), and hemoglobin (Hb; p = .027) levels, but significantly lower albumin (p = .000) levels.

Age, high blood pressure, and BUN, neutrophil, and WBC levels were predictors of the development of PRES in patients with preeclampsia and eclampsia. Early neuroimaging considering those predictors should be performed to diagnose PRES in patients with preeclampsia and eclampsia.

Increased plasma levels of monocyte chemoattractant protein-1 in patients with hepatitis B virus pre-S2 gene deletion mutation predict a higher risk of hepatocellular carcinoma recurrence after curative surgical resection.

BACKGROUND: Despite resection surgery as a curative therapy for hepatocellular carcinoma (HCC), the high rate of postoperative HCC recurrence remains a big challenge for patient survival. Chronic hepatitis B virus (HBV) infection is the most important risk factor for HCC. Deletion mutation in the HBV pre-S2 gene leads to expression of an essential viral oncoprotein called pre-S2 mutant and represents an independent prognostic biomarker for HCC recurrence after curative surgical resection. Additionally, cytokines are multifunctional secreted proteins and implicated in all stages of HBV-related HCC tumorigenesis. METHODS: This study aimed to identify the cytokines whose plasma levels were associated with pre-S2 gene deletion mutation and HCC recurrence and evaluate their potential to be combined with pre-S2 gene deletion mutation in predicting HCC recurrence. RESULTS: Among a panel of 27 cytokines examined, plasma levels of monocyte chemoattractant protein-1 (MCP-1) were significantly upregulated in patients with pre-S2 gene deletion mutation or HCC recurrence. MCP-1 was validated as an independent prognostic biomarker for HCC recurrence. Moreover, patients with both the presence of pre-S2 gene deletion mutation and high levels of MCP-1 displayed a higher risk of HCC recurrence than patients with either one or none of these two biomarkers. The combination of pre-S2 gene deletion mutation and MCP-1 levels exhibited a better prognostic performance for HCC recurrence than each biomarker alone. CONCLUSIONS: This study discovered that MCP-1 levels had a significance to be as a combination biomarker with pre-S2 gene deletion mutation providing an improved performance in predicting HCC recurrence after curative surgical resection.

5' preS1 Mutations To Prevent Large Envelope Protein Expression from Hepatitis B Virus Genotype A or Genotype D Markedly Increase Polymerase-Envelope Fusion Protein.

Hepatitis B virus (HBV) large (L) envelope protein is translated from 2.4-kb RNA. It contains preS1, preS2, and S domains and is detected in Western blotting as p39 and gp42. The 3.5-kb pregenomic RNA produces core and polymerase (P) proteins. We generated L-minus mutants of a genotype A clone and a genotype D clone from 1.1-mer or 1.3-mer construct, with the former overproducing pregenomic RNA. Surprisingly, mutating a preS1 ATG codon(s) or introducing a nonsense mutation soon afterwards switched secreted p39/gp42 to a p41/p44 doublet, with its amount further increased by a nonsense mutation in the core gene. A further-downstream preS1 nonsense mutation prevented p41/p44 production. Tunicamycin treatment confirmed p44 as the glycosylated form of p41. In this regard, splicing of 3.5-kb RNA to generate a junction at nucleotides (nt) 2447 to 2902 for genotype D enables translation of p43, with the N-terminal 47 residues of P protein fused to the C-terminal 371 residues of L protein. Indeed p41/p44 were detectable by an antibody against the N terminus of P protein and eliminated by a nonsense mutation at the 5' P gene or a point mutation to prevent that splicing. Therefore, lost L (and core) protein expression from the 1.1-mer or 1.3-mer construct markedly increased p41/p44 (p43), the P-L fusion protein. Cotransfection with an expression construct for L/M proteins reversed high extracellular p41/p44 associated with L-minus mutants, suggesting that L protein retains p43 in wild-type HBV to promote its intracellular degradation. Considering that p43 lacks N-terminal preS1 sequence critical for receptor binding, its physiological significance during natural infection and therapeutic potential warrant further investigation. IMPORTANCE The large (L) envelope protein of hepatitis B virus (HBV) is translated from 2.4-kb RNA and detected in Western blotting as p39 and gp42. Polymerase (P) protein is expressed at a low level from 3.5-kb RNA. The major spliced form of 3.5-kb RNA will produce a fusion protein between the first 47 residues of P protein and a short irrelevant sequence, although also at a low level. Another spliced form has the same P protein sequence fused to L protein missing its first 18 residues. We found that some point mutations to eliminate L and core protein expression from overlength HBV DNA constructs converted p39/gp42 to p41/gp44, which turned out to be the P-L fusion protein. Thus, the P-L fusion protein can be expressed at extremely high level when L protein expression is prevented. The underlying mechanism and functional significance of this variant form of L protein warrant further investigation.