[Clinical effect of tacrolimus in the treatment of myasthenia gravis in children].

OBJECTIVE: To evaluate the efficacy and safety of tacrolimus in the treatment of children with myasthenia gravis (MG). METHODS: A total of 28 children with MG were treated with tacrolimus. MG-Activities of Daily Living (MG-ADL) scale was used to assess clinical outcome and safety after 1, 3, 6, 9, and 12 months of treatment. RESULTS: After tacrolimus treatment, the MG-ADL score at 1, 3, 6, 9 and 12 months was lower than that at baseline (P<0.05), and the MG-ADL score showed a gradually decreasing trend. The response rates to tacrolimus treatment at 1, 3, 6, 9, and 12 months were 59%, 81%, 84%, 88%, and 88% respectively. At 6, 9, 12, and 18 months of treatment, 4, 13, 14, and 15 children respectively were withdrawn from prednisone. No recurrence was observed during treatment. Major adverse reactions/events were asymptomatic reduction in blood magnesium in 5 children and positive urine occult blood in 1 child, which turned negative without special treatment, and tacrolimus was not stopped due to such adverse reactions/events. One child was withdrawn from tacrolimus due to recurrent vomiting. According to CYP3A5 genotypes, all of the patients were divided into two groups: slow metabolic type (n=19) and non-slow metabolic type (fast metabolic type + intermediate type; n=9). The non-slow metabolism group received a higher dose of tacrolimus, but had a lower trough concentration of tacrolimus than the slow metabolism group (P<0.05). The slow metabolism group had a higher response rates to tacrolimus treatment than the non-slow metabolism group (P<0.05). CONCLUSIONS: Tacrolimus appears to be effective and safe in the treatment of children with MG and is thus an option for immunosuppressive therapy. CYP3A5 genotyping has a certain guiding significance for determining the dosage of tacrolimus.

Combining 53BP1 with BRCA1 as a biomarker to predict the sensitivity of poly(ADP-ribose) polymerase (PARP) inhibitors.

Over half of patients with BRCA1-deficient cancers do not respond to treatment with poly(ADP-ribose) polymerase (PARP) inhibitors. In this study, we report that a combination of 53BP1 and BRCA1 may serve as a biomarker of PARP inhibitor sensitivity. Based on the mRNA levels of four homologous recombination repair (HR) genes and PARP inhibitor sensitivity, we selected BRCA1-deficient MDA-MB-436 cells to conduct RNA interference. Reducing expression of 53BP1, but not the other three HR genes, was found to lower simmiparib sensitivity. Additionally, we generated 53BP1-/-/BRCA1-/- clonal variants by the transcription activator-like effector nuclease (TALEN) technique and found that depleting 53BP1 impaired PARP inhibitor sensitivity with a 36.7-fold increase in their IC50 values. Consistent with its effect on PARP inhibitor sensitivity, 53BP1 loss alleviated cell cycle arrest and apoptosis and partially restored HR function. Importantly, 53BP1 depletion dramatically reduced the ability of PARP inhibitors to suppress tumor growth in vivo. The inhibition rate of simmiparib was 74.16% for BRCA1-deficient MDA-MB-436 xenografts, but only 7.79% for 53BP1/BRCA1-deficient xenografts. Re-expressing 53BP1 in the dual-deficient cells restored PARP inhibitor sensitivity and the levels of HR regulators. Considering that at least 10% of BRCA1-deficient breast and ovarian cancers have reduced expression of 53BP1, using a combination of 53BP1 with BRCA1 as a biomarker for patient selection should reduce the number of patients undergoing futile treatment with PARP inhibitors.

Identification of [1,2,4]Triazolo[4,3-a]pyrazine PARP1 inhibitors with overcome acquired resistance activities.

Poly(ADP-ribose) polymerase 1 (PARP1) inhibitors can selectively kill homologous recombination (HR) deficient cancer cells and elicit anticancer effect through a mechanism of synthetic lethality. In this study, we designed, synthesized and pharmacologically evaluated a series of [1,2,4]triazolo[4,3-a]pyrazine derivatives as a class of potent PARP1 inhibitors. Among them, compounds 17m, 19a, 19c, 19e, 19i and 19k not only displayed more potent inhibitory activities (IC50s < 4.1 nM) than 9 and 1 against PARP1, but also exhibited nanomolar range of antiproliferative effects against MDA-MB-436 (BRCA1-/-, IC50s < 1.9 nM) and Capan-1 (BRCA2-/-, IC50s < 21.6 nM) cells. Notably, 19k significantly inhibited proliferation of resistant Capan-1 cells (IC50s < 0.3 nM). Collectively, the newly discovered PARP1 inhibitors act as a useful pharmacological tool for investigating the mechanism of acquired resistance to PARP1 inhibitors, and may also represent promising therapeutic agents for the treatment of HR deficient cancers with the potential to overcome the acquired resistance.

Thioparib inhibits homologous recombination repair, activates the type I IFN response, and overcomes olaparib resistance.

Poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have shown great promise for treating BRCA-deficient tumors. However, over 40% of BRCA-deficient patients fail to respond to PARPi. Here, we report that thioparib, a next-generation PARPi with high affinity against multiple PARPs, including PARP1, PARP2, and PARP7, displays high antitumor activities against PARPi-sensitive and -resistant cells with homologous recombination (HR) deficiency both in vitro and in vivo. Thioparib treatment elicited PARP1-dependent DNA damage and replication stress, causing S-phase arrest and apoptosis. Conversely, thioparib strongly inhibited HR-mediated DNA repair while increasing RAD51 foci formation. Notably, the on-target inhibition of PARP7 by thioparib-activated STING/TBK1-dependent phosphorylation of STAT1, triggered a strong induction of type I interferons (IFNs), and resulted in tumor growth retardation in an immunocompetent mouse model. However, the inhibitory effect of thioparib on tumor growth was more pronounced in PARP1 knockout mice, suggesting that a specific PARP7 inhibitor, rather than a pan inhibitor such as thioparib, would be more relevant for clinical applications. Finally, genome-scale CRISPR screening identified PARP1 and MCRS1 as genes capable of modulating thioparib sensitivity. Taken together, thioparib, a next-generation PARPi acting on both DNA damage response and antitumor immunity, serves as a therapeutic potential for treating hyperactive HR tumors, including those resistant to earlier-generation PARPi.

Protective effects of the ethanolic extract of Melia toosendan fruit against colon cancer.

Colorectal cancer is one of the leading causes of death in the world. Plant-derived products have proven to be valuable sources for discovery and development of unique anticancer drugs. In this study, the inhibitory effects of ethanolic extract of Melia toosendan fruit (EMTF), a traditional medicine in the Chinese Pharmacopeia were evaluated in vitro and in vivo against colon cancer. Human colon cancer cells SW480 and murine colorectal adenocarcinoma cells CT26 were used to investigate cell proliferation. The results showed that EMTF inhibited cell proliferation of SW480 and CT26 by promoting apoptosis as indicated by nuclear chromatin condensation and DNA fragmentation. Through increasing mitochondrial membrane permeability and cytochrome c release from mitochondria, EMTF induced caspase-9 activity which further activated caspase-3 and poly(ADP-ribose) polymerase cleavage, leading the tumor cells to apoptosis. The in vivo results confirmed reduction of tumor volume and apoptotic effects and the side effects were not induced by EMTF. Therefore, EMTF may be an effective chemotherapeutic agent for colon cancer treatment.

Guillain-Barré syndrome (GBS) complicated by rhabdomyolysis (RML): Case reports of 2 children and literature review.

We initially described two children who developed Guillain-Barré syndrome (GBS) complicated by rhabdomyolysis (RML), and reviewed five adult patients from the literature. Through analysis of the clinical features, laboratory examination, treatment and prognostic data from these seven patients, we found that when GBS "meets" RML, the most prominent characteristics were the following: male dominance; limb weakness, pain and respiratory failure could be caused by multiple factors; limb weakness and respiratory muscle paralysis were more serious than with GBS alone; and the probability of mechanical ventilation was increased. Neuroelectrophysiological studies revealed axonal lesions. Close monitoring and timely identification and intervention to remedy potentially fatal complications such as electrolyte disorder multisystem complications and kidney injury are crucial. With plasma exchange, peritoneal dialysis and supportive treatment, the long-term outcome of most patients was satisfactory.

Neurologic Manifestations as Initial Clinical Presentation of Familial Hemophagocytic Lymphohistiocytosis Type2 Due to PRF1 Mutation in Chinese Pediatric Patients.

Familial hemophagocytic lymphohistiocytosis Type 2 (FHL2) associated central nervous system (CNS) involvement is less understood in children, especially when considering neurologic manifestations as part of the initial presentation. We conducted a retrospective review of the clinical manifestations and genetic abnormality of four Han Chinese children with FHL2 who were patients at the neurology department of Beijing Children's Hospital from November 2015 to October 2018. These four patients initially manifested CNS symptoms in their disease presentation, and all four patients were misdiagnosed as having ademyelinating disease, such as acute disseminated encephalomyelitis and multiple sclerosis. Given these misdiagnoses, it is important that general physicians and pediatricians maintain awareness of the possibility of FHL2 as a differential diagnosis. These four cases included neurologic manifestations including seizures, ataxia, spasticity, gait disorder, and coma. Bilateral abnormal signals in the cerebrum, including in white matter, gray matter, and junctions were discovered. Enhanced magnetic resonance imaging (MRI) in these patients showed spot or ring enhancement and/or hemorrhage. These patients all possessed a compound heterozygote mutation PRF1 gene. Whole exome sequencing analysis revealed seven different mutations (three novel mutations) spread over the PRF1 gene and a heterozygous missense mutation c.1349C > T [p.T450M] that was present in two patients. Three novel mutations, c.634T > C[p.Y212H], c.1083_1094del[p.361_364del], and c.1306G > T [p.D436Y], were discovered and through in silico analysis were discovered to be deleterious. Neurologic manifestations were the initial symptoms of FHL2 in these patients in addition to the expected leukopenia and hepatosplenomegaly. Whole exome sequencing of PRF1 for patients with similar presentations would facilitate prompt and accurate diagnosis and treatment.

Asiatic acid induces colon cancer cell growth inhibition and apoptosis through mitochondrial death cascade.

Cancer is one of the leading causes of death in the world. The triterpenoid compound asiatic acid derived from the tropical medicinal plant Centella asiatica displays cytotoxic activity on fibroblast cells and several other kinds of cells. The present work studies asiatic acid-mediated growth inhibition of cancer cells and the underlying mechanism. Asiatic acid markedly inhibited cancer cell proliferation. Apoptosis of SW480 human colon cancer cells was induced by asiatic acid as shown by flow cytometry, DNA fragmentation and nuclear chromatin condensation experiments. Through increasing mitochondrial membrane permeability and cytochrome c release from mitochondria into cytosol, asiatic acid induced caspase-9 activity, which further activated caspase-3 and poly(ADP-ribose) polymerase cleavage resulting in irreversible apoptotic death in the tumor cells. Taken together, these results suggest that mitochondrial death apoptosis cascade plays very important roles in asiatic acid-induced cancer apoptosis.

Toll-like receptor 4-mediated immunoregulation by the aqueous extract of Mori Fructus.

The aqueous extract of Mori Fructus (MF) exerts a change of phenotype and a cytoprotective effect in macrophages. The present study was carried out to investigate the immunomodulating activity of MF on the expression of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), co-stimulatory molecules and also interferon-gamma (IFN-gamma) in macrophages and splenocytes. Toll-like receptor 4 (TLR4) is a promising molecular target for immune-modulating drugs. It was hypothesized that one possible upstream signaling pathway leading to immunoregulation of MF may be mediated by TLRs. Multiple signaling molecules (NF-kappaB, ERK1/2, p38 and JNK) of the TLR4 signaling pathway were also detected. It was found that MF increased NO production and TNF-alpha secretion in RAW 264.7 and peritoneal macrophages, co-stimulatory molecules expression in peritoneal macrophages and IFN-gamma expression in splenocytes. Further studies indicated that MF could significantly induce the phosphorylation of signal molecules of MAPKs and the degradation of IkappaBalpha which finally led to the activation and nuclear translocation of nuclear factor-kappaB (NF-kappaB) for the target gene expression. All those notions disclosed that the aqueous extract MF is a new TLR4 activator, which induces a Th1 immune response as a consequence of induction of cytokines secretion, especially TNF-alpha and IFN-gamma.

Rehmannia inhibits adipocyte differentiation and adipogenesis.

Rehmannia glutinosa, a Traditional Chinese Medicine (TCM), has been used to increase physical strength. Here, we report that Rehmannia glutinosa extract (RE) inhibits adipocyte differentiation and adipogenesis. RE impairs differentiation of 3T3-L1 preadipocytes in a dose-dependent manner. At the molecular level, treatment with RE inhibits expression of the key adipocyte differentiation regulator C/EBPbeta, as well as C/EBPalpha and the terminal marker protein 422/aP2, during differentiation of preadipocytes into adipocytes. Additionally, RE inhibits the mitotic clonal expansion (MCE) process of adipocyte differentiation, and RE prevents localization of C/EBPbeta to the centromeres. RE also prevents high fat diet (HFD) induced weight gain and adiposity in rats. Taken together, our results indicate that Rehmannia glutinosa extract inhibits preadipocyte differentiation and adipogenesis in cultured cells and in rodent models of obesity.

RNA secondary structures located in the interchromosomal region of human ACAT1 chimeric mRNA are required to produce the 56-kDa isoform.

We have previously reported that the human ACAT1 gene produces a chimeric mRNA through the interchromosomal processing of two discontinuous RNAs transcribed from chromosomes 1 and 7. The chimeric mRNA uses AUG(1397-1399) and GGC(1274-1276) as translation initiation codons to produce normal 50-kDa ACAT1 and a novel enzymatically active 56-kDa isoform, respectively, with the latter being authentically present in human cells, including human monocyte-derived macrophages. In this work, we report that RNA secondary structures located in the vicinity of the GGC(1274-1276) codon are required for production of the 56-kDa isoform. The effects of the three predicted stem-loops (nt 1255-1268, 1286-1342 and 1355-1384) were tested individually by transfecting expression plasmids into cells that contained the wild-type, deleted or mutant stem-loop sequences linked to a partial ACAT1 AUG open reading frame (ORF) or to the ORFs of other genes. The expression patterns were monitored by western blot analyses. We found that the upstream stem-loop(1255-1268) from chromosome 7 and downstream stem-loop(1286-1342) from chromosome 1 were needed for production of the 56-kDa isoform, whereas the last stem-loop(1355-1384) from Chromosome 1 was dispensable. The results of experiments using both monocistronic and bicistronic vectors with a stable hairpin showed that translation initiation from the GGC(1274-1276) codon was mediated by an internal ribosome entry site (IRES). Further experiments revealed that translation initiation from the GGC(1274-1276) codon requires the upstream AU-constituted RNA secondary structure and the downstream GC-rich structure. This mechanistic work provides further support for the biological significance of the chimeric nature of the human ACAT1 transcript.

Circulating microRNA signature for the diagnosis of childhood dilated cardiomyopathy.

Circulating miRNAs are proposed as a biomarker of heart disease. This study evaluated whether circulating miRNAs could be used as a biomarker for childhood dilated cardiomyopathy (CDCM). A total of 28 participants were enrolled in a discovery set, including patients with CDCM (n = 16) and healthy children (n = 12). The cardiac function of patients with CDCM was characterized by echocardiography and serum miRNA profiles of all participants were assessed by miRNA sequencing. After miRNA profiling, we quantitatively confirmed 148 regulated miRNAs in patients with CDCM compared with healthy subjects, and none were downregulated. Validation of candidate miRNAs was assessed by quantitative real-time polymerase chain reaction in other patients with CDCM (n = 30) and healthy controls (n = 16). A unique signature comprising mir-142-5p, mir-143-3p, mir-27b-3p, and mir-126-3p differentiated patients with CDCM from healthy subjects. Importantly, we observed an increase in mir-126-3p or let-7g in parallel with a robust decrease in the ejection fraction in patients with CDCM, which could differentiate heart failure patients from non-heart failure patients with CDCM. Moreover, mir-126-3p and let-7g were significantly negatively associated with the left ventricular ejection fraction. This study shows that a signature of four serum miRNAs may be a potential biomarker for diagnosing CDCM and assessing heart failure.

Acidic oligosaccharide sugar chain, a marine-derived oligosaccharide, activates human glial cell line-derived neurotrophic factor signaling.

Gial derived neurotrophic factor (GDNF) modulates neuronal cell differentiation during development and protects against neurodegeneration by preventing apoptosis at maturity. GDNF's role in tissue maintenance has generated interest in the therapeutic potential of GDNF in treating neurological disorders such as Parkinson's disease. Heparan sulfate has been shown to be essential for GDNF signaling and altering the levels of heparan sulfate promotes or inhibits GDNF functional activity. To search for other oligosaccharides capable of modulating GDNF activity as potential therapeutic molecules, we investigated the effect of acidic oligosaccharide sugar chain (AOSC) and its sulfated derivative on GDNF induced neurotrophic events by using Western-blotting, immunofluorescence cell staining, and immunoprecipitation techniques in PC12 cells expressing the GDNF receptors GFR alpha 1-Ret. AOSC significantly improved the neurite outgrowth and activated c-Ret phosphorylation in PC12-GFR alpha 1-Ret cells, but its sulfated derivative inhibited GDNF activity. Studies to understand the opposing biological effects of AOSC and its sulfated derivative on GDNF activity demonstrated that reduced GDNF binding to PC12-GFR alpha 1-Ret cell surface in the presence of the sulfated derivative likely suppressed GDNF activity as both AOSC and its sulfated derivatives had similar binding affinities to GDNF. This study illustrates the importance of oligosaccharide structure and charge on influencing GDNF activity and the potential use of oligosaccharides in modulating GDNF activity for therapeutic purposes.

Human acyl-CoA:cholesterol acyltransferase 2 gene expression in intestinal Caco-2 cells and in hepatocellular carcinoma.

Humans express two ACAT (acyl-CoA:cholesterol acyltransferase) genes, ACAT1 and ACAT2. ACAT1 is ubiquitously expressed, whereas ACAT2 is primarily expressed in intestinal mucosa and plays an important role in intestinal cholesterol absorption. To investigate the molecular mechanism(s) responsible for the tissue-specific expression of ACAT2, we identified five cis-elements within the human ACAT2 promoter, four for the intestinal-specific transcription factor CDX2 (caudal type homeobox transcription factor 2), and one for the transcription factor HNF1alpha (hepatocyte nuclear factor 1alpha). Results of luciferase reporter and electrophoretic mobility shift assays show that CDX2 and HNF1alpha exert a synergistic effect, enhancing the ACAT2 promoter activity through binding to these cis-elements. In undifferentiated Caco-2 cells, the ACAT2 expression is increased when exogenous CDX2 and/or HNF1alpha are expressed by co-transfection. In differentiated Caco-2 cells, the ACAT2 expression significantly decreases when the endogenous CDX2 or HNF1alpha expression is suppressed by using RNAi (RNA interference) technology. The expression levels of CDX2, HNF1alpha, and ACAT2 are all greatly increased when the Caco-2 cells differentiate to become intestinal-like cells. These results provide a molecular mechanism for the tissue-specific expression of ACAT2 in intestine. In normal adult human liver, CDX2 expression is not detectable and the ACAT2 expression is very low. In the hepatoma cell line HepG2 the CDX2 expression is elevated, accounting for its elevated ACAT2 expression. A high percentage (seven of fourteen) of liver samples from patients affected with hepatocellular carcinoma exhibited elevated ACAT2 expression. Thus, the elevated ACAT2 expression may serve as a new biomarker for certain form(s) of hepatocellular carcinoma.

Integration of Receptor Tyrosine Kinases Determines Sensitivity to PI3Kα-selective Inhibitors in Breast Cancer.

PI3Kα-selective inhibitor BYL719 is currently in phase II/III clinical trial for the treatment of breast cancer, but highly variable response has been observed among patients. We sought to discover predictive biomarker for the efficacy of BYL719 by dissecting the proliferative signaling pathway mediated by PI3K in breast cancer. BYL719 concurrently inhibited the phosphorylation of AKT and ERK in PIK3CA-mutated human breast cancer cells. PI3K-regulated ERK phosphorylation was independent of canonical PDK1/AKT/mTOR pathway, while it was associated with RAF/MEK. Hyper-activation of EGFR or RAS abrogated inhibition of ERK phosphorylation by BYL719. Furthermore, hyper-activation of receptor tyrosine kinases (RTKs) including EGFR, c-MET, FGFR and HER3 but not IGF-1R restored ERK phosphorylation and cell viability suppressed by BYL719, suggesting the discriminative functions of RTKs in cell signaling and proliferation. By profiling 22 breast cancer cell lines, we found that BYL719 was more potent in cell lines where phosphorylation of both AKT and ERK was attenuated than those where only AKT phosphorylation was inhibited. The potency of BYL719 was further found to be significantly correlated with the expression profile of RTKs in breast cancer cells. Specifically, overexpression of EGFR, c-MET and/or FGFR1 forecasted resistance, while overexpression of IGF-1R and/or HER2 predicted sensitivity to BYL719 in breast cancer cells. Similar correlation between BYL719 efficacy and expression profile of RTKs was found in patient-derived xenograft models of breast cancer. Thus, inhibition of ERK phosphorylation by PI3Kα inhibitor BYL719 contributes to its antitumor efficacy and is determined by the converged signaling from RTKs. The expression profile of RTKs in breast cancer tissue could be potentially developed as a predictive biomarker for the efficacy of PI3Kα inhibitors.

Novel PARP1/2 inhibitor mefuparib hydrochloride elicits potent in vitro and in vivo anticancer activity, characteristic of high tissue distribution.

The approval of poly(ADP-ribose) polymerase (PARP) inhibitor AZD2281 in 2014 marked the successful establishment of the therapeutic strategy targeting homologous recombination repair defects of cancers in the clinic. However, AZD2281 has poor water solubility, low tissue distribution and relatively weak in vivo anticancer activity, which appears to become limiting factors for its clinical use. In this study, we found that mefuparib hydrochloride (MPH) was a potent PARP inhibitor, possessing prominent in vitro and in vivo anticancer activity. Notably, MPH displayed high water solubility (> 35 mg/ml) and potent PARP1/2 inhibition in a substrate-competitive manner. It reduced poly(ADP-ribose) (PAR) formation, enhanced γH2AX levels, induced G2/M arrest and subsequent apoptosis in homologous recombination repair (HR)-deficient cells. Proof-of-concept studies confirmed the MPH-caused synthetic lethality. MPH showed potent in vitro and in vivo proliferation and growth inhibition against HR-deficient cancer cells and synergistic sensitization of HR-proficient xenografts to the anticancer drug temozolomide. A good relationship between the anticancer activity and the PARP inhibition of MPH suggested that PAR formation and γH2AX accumulation could serve as its pharmacodynamic biomarkers. Its high bioavailability (40%~100%) and high tissue distribution in both monkeys and rats were its most important pharmacokinetic features. Its average concentrations were 33-fold higher in the tissues than in the plasma in rats. Our work supports the further clinical development of MPH as a novel PARP1/2 inhibitor for cancer therapy.

Poly(ADP-ribose)polymerase (PARP) inhibition and anticancer activity of simmiparib, a new inhibitor undergoing clinical trials.

Poly(ADP-ribose)polymerase (PARP)1/2 inhibitors have been proved to be clinically effective anticancer drugs. Here we report a new PARP1/2 inhibitor, simmiparib, displaying apparently improved preclinical anticancer activities relative to the first approved inhibitor olaparib. Simmiparib inhibited PARP1/2 approximately 2-fold more potently than olaparib, with more than 90-fold selectivity over the other tested PARP family members. Simmiparib and olaparib caused similar cellular PARP1-DNA trapping. Simmiparib selectively induced the accumulation of DNA double-strand breaks, G2/M arrest and apoptosis in homologous recombination repair (HR)-deficient cells. Consistently, simmiparib showed 26- to 235-fold selectivity in its antiproliferative activity against HR-deficient cells over the corresponding isogenic HR-proficient cells. Notably, its antiproliferative activity was 43.8-fold more potent than that of olaparib in 11 HR-deficient cancer cell lines. Simmiparib also potentiated the proliferative inhibition of several conventional anticancer drugs. Simmiparib reduced the poly(ADP-ribose) formation in HR-deficient cancer cells and xenografts. When orally administered to nude mice bearing xenografts, simmiparib revealed excellent pharmacokinetic properties. Simmiparib caused approximately 10-fold greater growth inhibition than olaparib against HR-deficient human cancer cell- or tissue-derived xenografts in nude mice. Collectively, these findings support the undergoing clinical trials of simmiparib.

Requirements of myocyte-specific enhancer factor 2A in zebrafish cardiac contractility.

Myocyte-specific enhancer factor 2A (MEF2A) regulates a broad range of fundamental cellular processes including cell division, differentiation and death. Here, we tested the hypothesis that MEF2A is required in cardiac contractility employing zebrafish as a model organism. MEF2A is highly expressed in heart as well as somites during zebrafish embryogenesis. Knock-down of MEF2A in zebrafish impaires the cardiac contractility and results in sarcomere assembly defects. Dysregulation of cardiac genes in MEF2A morphants suggests that sarcomere assembly disturbances account for the cardiac contractile deficiency. Our studies suggested that MEF2A is essential in cardiac contractility.

Interleukin-21 inhibits HBV replication in vitro.

BACKGROUND: Cytokines are crucial factors in the non-cytolytic antiviral process to inhibit HBV gene expression and replication. Interleukin (IL)-21 has been suggested to play an important role in HBV infection, but it remains unknown whether IL-21 can inhibit HBV replication or how it inhibits HBV replication. METHODS: In this study, we investigated the influence of IL-21 on HBV replication based on human hepatoma Huh7.93 cells co-cultured with human peripheral blood mononuclear cells (PBMCs) and the possible correlation among IL-21, interferon-γ, tumour necrosis factor-α and IL-10. RESULTS: We demonstrated that the decrease of IL-21 expression and the increase of IL-10 expression in PBMCs could promote HBV replication in vitro. We further revealed that IL-21 is not only able to effectively suppress HBV replication directly but also reduce HBV replication by inhibition of IL-10 secretion. CONCLUSIONS: Our results provide important evidence for the non-cytolytic antiviral mechanism mediated by cytokines and their interactions in chronic hepatitis B.