NS1-mediated enhancement of MVC transcription and replication promoted by KAT5/H4K12ac.

Histone modifications function in both cellular and viral gene expression. However, the roles of acetyltransferases and histone acetylation in parvoviral infection remain poorly understood. In the current study, we found the histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), promoted the replication and transcription of parvovirus minute virus of canines (MVC). Notably, the expression of host acetyltransferases KAT5, GTF3C4, and KAT2A was increased in MVC infection, as well as H4 acetylation (H4K12ac). KAT5 is not only responsible for H4K12ac but also crucial for viral replication and transcription. The viral nonstructural protein NS1 interacted with KAT5 and enhanced its expression. Further study showed that Y44 in KAT5, which may be tyrosine-phosphorylated, is indispensable for NS1-mediated enhancement of KAT5 and efficient MVC replication. The data demonstrated that NS1 interacted with KAT5, which resulted in an enhanced H4K12ac level to promote viral replication and transcription, implying the epigenetic addition of H4K12ac in viral chromatin-like structure by KAT5 is vital for MVC replication.IMPORTANCEParvoviral genomes are chromatinized with host histones. Therefore, histone acetylation and related acetyltransferases are required for the virus to modify histones and open densely packed chromatin structures. This study illustrated that histone acetylation status is important for MVC replication and transcription and revealed a novel mechanism that the viral nonstructural protein NS1 hijacks the host acetyltransferase KAT5 to enhance histone acetylation of H4K12ac, which relies on a potential tyrosine phosphorylation site, Y44 in KAT5. Other parvoviruses share a similar genome organization and coding potential and may adapt a similar strategy for efficient viral replication and transcription.

Predictive factors that influence the clinical efficacy of umbilical cord-derived mesenchymal stromal cells in the treatment of type 2 diabetes mellitus.

BACKGROUND: Our previous single-center, randomized, double-blinded, placebo-controlled phase 2 study evaluated the safety and effectiveness of human umbilical cord mesenchymal stromal cell (UC-MSC) transfusion for treating patients with type 2 diabetes mellitus (T2DM). Indeed, this potential treatment strategy was able to reduce insulin use by half in a considerable number of patients. However, many other patients' responses to UC-MSC transfusion were insignificant. The selection of patients who might benefit from UC-MSC treatment is crucial from a clinical standpoint. METHODS: In this post hoc analysis, 37 patients who received UC-MSC transfusions were divided into two groups based on whether their glycated hemoglobin (hemoglobin A1c, or HbA1c) level was less than 7% after receiving UC-MSC treatment. The baseline differences between the two groups were summarized, and potential factors influencing efficacy of UC-MSCs for T2DM were analyzed by univariate and multivariate logistic regression. The correlations between the relevant hormone levels and the treatment effect were further analyzed. RESULTS: At the 9-week follow-up, 59.5% of patients achieved their targeted HbA1c level. Male patients with lower baseline HbA1c and greater C-peptide area under the curve (AUCC-pep) values responded favorably to UC-MSC transfusion, according to multivariate analysis. The effectiveness of UC-MSCs transfusion was predicted by AUCC-pep (cutoff value: 14.22 ng/h/mL). Further investigation revealed that AUCC-pep was increased in male patients with greater baseline testosterone levels. CONCLUSIONS: Male patients with T2DM with greater AUCC-pep may be more likely to respond clinically to UC-MSC therapy, and further large-scale multi-ethnic clinical studies should be performed to confirm the conclusion.

N4-acetylcytidine regulates the replication and pathogenicity of enterovirus 71.

Chemical modifications are important for RNA function and metabolism. N4-acetylcytidine (ac4C) is critical for the translation and stability of mRNA. Although ac4C is found in RNA viruses, the detailed mechanisms through which ac4C affects viral replication are unclear. Here, we reported that the 5' untranslated region of the enterovirus 71 (EV71) genome was ac4C modified by the host acetyltransferase NAT10. Inhibition of NAT10 and mutation of the ac4C sites within the internal ribosomal entry site (IRES) suppressed EV71 replication. ac4C enhanced viral RNA translation via selective recruitment of PCBP2 to the IRES and boosted RNA stability. Additionally, ac4C increased the binding of RNA-dependent RNA polymerase (3D) to viral RNA. Notably, ac4C-deficient mutant EV71 showed reduced pathogenicity in vivo. Our findings highlighted the essential role of ac4C in EV71 infection and provided insights into potential antiviral treatments.

Bone mesenchymal stromal cell-derived small extracellular vesicles inhibit inflammation and ameliorate sepsis via delivery of microRNA-21a-5p.

BACKGROUND AIMS: Sepsis is a potentially life-threatening disease that results from a severe systemic inflammatory response due to infection. Mesenchymal stromal cell-derived small extracellular vesicles (MSC sEVs) are able to transfer bioactive molecules and have been demonstrated to play an important role in the pathophysiological process of sepsis. Herein the authors aimed to investigate the potential role and downstream molecular mechanism of MSC sEVs in sepsis. METHODS: MSC sEVs were acquired by ultracentrifugation and then injected into a cecal ligation and puncture mouse model. The efficacy of MSC sEVs in both in vitro and in vivo models of sepsis was evaluated. RESULTS: MSC sEV therapy improved survival, reduced sepsis-induced inflammation, attenuated pulmonary capillary permeability and improved liver and kidney function in septic mice. In addition, the authors found that microRNA-21a-5p (miR-21a-5p) was highly enriched in MSC sEVs, could be transferred to recipient cells, inhibited inflammation and increased survival in septic mice. Furthermore, the authors demonstrated that MSC sEV miR-21a-5p suppressed inflammation by targeting toll-like receptor 4 and programmed cell death 4. The therapeutic efficacy of MSC sEVs was partially abrogated by transfection with miR-21a-5p inhibitors. CONCLUSIONS: Collectively, the authors' data suggest that miR-21a-5p-bearing MSC sEVs may be a prospective and effective sepsis therapeutic strategy.

Human umbilical cord mesenchymal stromal cell small extracellular vesicle transfer of microRNA-223-3p to lung epithelial cells attenuates inflammation in acute lung injury in mice.

BACKGROUND: Acute lung injury (ALI), manifested as strong pulmonary inflammation and alveolar epithelial damage, is a life-threatening disease with high morbidity and mortality. Small extracellular vesicles (sEVs), secreted by multiple types of cells, are critical cellular communication mediators and can inhibit inflammation by transferring bioactive molecules, such as microRNAs (miRNAs). Thus, we hypothesized that sEVs derived from mesenchymal stromal cells (MSC sEVs) could transfer miRNAs to attenuate inflammation of lung epithelial cells during ALI. METHODS: C57BL/6 male mice were intratracheally administered LPS (10 mg/kg). Six hours later, the mice were randomly administered with MSC sEVs (40 µg per mouse in 150 µl of saline), which were collected by ultracentrifugation. Control group received saline administration. After 48 h, the mice were sacrificed to evaluate pulmonary microvascular permeability and inflammatory responses. In vitro, A549 cells and primary human small airway epithelial cells (SAECs) were stimulated with LPS with or without MSC sEVs treatment. RESULTS: In vitro, MSC sEVs could also inhibit the inflammation induced by LPS in A549 cells and SAECs (reducing TNF-α, IL-1ß, IL-6 and MCP-1). Moreover, MSC sEV treatment improved the survival rate, alleviated pulmonary microvascular permeability, and inhibited proinflammatory responses (reducing TNF-α, IL-1ß, IL-6 and JE-1) in ALI mice. Notably, miR-223-3p was found to be served as a critical mediator in MSC sEV-induced regulatory effects through inhibition of poly (adenosine diphosphate-ribose) polymerase-1 (PARP-1) in lung epithelial cells. CONCLUSIONS: Overall, these findings suggest that MSC sEVs may offer a novel promising strategy for ALI.

Human mesenchymal stromal cells small extracellular vesicles attenuate sepsis-induced acute lung injury in a mouse model: the role of oxidative stress and the mitogen-activated protein kinase/nuclear factor kappa B pathway.

BACKGROUND AIMS: Acute lung injury (ALI) secondary to sepsis is a complex disease associated with high morbidity and mortality. Mesenchymal stem cells (MSCs) and their conditioned medium have been demonstrated to reduce alveolar inflammation, improve lung endothelial barrier permeability and modulate oxidative stress in vivo and in vitro. Recently, MSCs have been found to release small extracellular vesicles (sEVs) that can deliver functionally active biomolecules into recipient cells. The authors' study was designed to determine whether sEVs released by MSCs would be effective in sepsis-induced ALI mice and to identify the potential mechanisms. METHODS: A total of 6 h after cercal ligation and puncture, the mice received saline, sEV-depleted conditioned medium (sEVD-CM) or MSC sEVs via the tail vein. RESULTS: The administration of MSC sEVs improved pulmonary microvascular permeability and inhibited both histopathological changes and the infiltration of polymorphonuclear neutrophils into lung tissues. In addition, the activities of antioxidant enzymes were significantly increased in the group treated with sEVs compared with the saline and sEVD-CM groups, whereas lipid peroxidation was significantly decreased. Furthermore, sEVs were found to possibly inhibit phosphorylation of the mitogen-activated protein kinase/nuclear factor kappa B (MAPK/NF-κB) pathway and degradation of IκB but increase the activities of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1. CONCLUSIONS: These findings suggest that one of the effective therapeutic mechanisms of sEVs against sepsis-induced ALI may be associated with upregulation of anti-oxidative enzymes and inhibition of MAPK/NF-κB activation.

N6-methyladenosine modification and METTL3 modulate enterovirus 71 replication.

N6-methyladenosine (m6A) constitutes one of the most abundant internal RNA modifications and is critical for RNA metabolism and function. It has been previously reported that viral RNA contains internal m6A modifications; however, only recently the function of m6A modification in viral RNAs has been elucidated during infections of HIV, hepatitis C virus and Zika virus. In the present study, we found that enterovirus 71 (EV71) RNA undergoes m6A modification during viral infection, which alters the expression and localization of the methyltransferase and demethylase of m6A, and its binding proteins. Moreover, knockdown of m6A methyltransferase resulted in decreased EV71 replication, whereas knockdown of the demethylase had the opposite effect. Further study showed that the m6A binding proteins also participate in the regulation of viral replication. In particular, two m6A modification sites were identified in the viral genome, of which mutations resulted in decreased virus replication, suggesting that m6A modification plays an important role in EV71 replication. Notably, we found that METTL3 interacted with viral RNA-dependent RNA polymerase 3D and induced enhanced sumoylation and ubiquitination of the 3D polymerase that boosted viral replication. Taken together, our findings demonstrated that the host m6A modification complex interacts with viral proteins to modulate EV71 replication.

Berberine: A Traditional Natural Product With Novel Biological Activities.

CONTEXT: Having been used for thousands of years to treat gastrointestinal diseases, the natural isoquinoline alkaloid, berberine, has exhibited a wide spectrum of biochemical and pharmacological effects in studies of recent years. OBJECTIVE: The review intended to examine the many novel bioactivities of berberine, including antidiabetic, anticancer, neuroprotective, anti-inflammatory, and anti-atherosclerotic actions. DESIGN: The research team searched the MEDLINE database using PubMed, using different keyword combinations, including berberine AND diabetes, berberine AND cancer, berberine AND (neuron OR brain), berberine AND inflammation, and "berberine AND atherosclerosis to find studies evaluating the various effects exerted berberine. CONCLUSION: Berberine is a promising multipotent agent to combat diabetes, cancer, Alzheimer's disease, and other diseases.

Arsenic trioxide inhibits the differentiation of fibroblasts to myofibroblasts through nuclear factor erythroid 2-like 2 (NFE2L2) protein and the Smad2/3 pathway.

BACKGROUND: Tissue contraction and the extracellular matrix deposition are part of the pathogenesis of hypertrophic scars. The transcriptional factor NFE2L2 inhibits fibroblast differentiation in idiopathic pulmonary fibrosis and promotes myofibroblast dedifferentiation. Our previous study showed that the transcription factor NFE2L2 was strongly induced on treatment with arsenic trioxide (ATO). OBJECTIVE: The present study sought to investigate the effect of ATO on myofibroblast formation to determine its potential role in hypertrophic scar treatment. METHODS: Small interfering RNA against NFE2L2 was used on treatment with ATO in human skin myofibroblasts. The expression levels of fibrosis markers were assessed by reverse transcription polymerase chain reaction, western blot, and immunofluorescence staining. The transforming growth factor-ß1 (TGF-ß1)/Smad2/3 signaling was detected by western blot. A rabbit ear model was used to evaluate the antifibrotic role of ATO. RESULTS: At the cellular level, ATO abolished fibroblast differentiation in response to TGF-ß1. ATO reduced TGF-ß1-induced reactive oxygen species accumulation through increased expression of the antioxidant gene HO-1 in fibroblasts. In addition, ATO promoted the nuclear translocation of NFE2L2 and inhibited the phosphorylation of Smad2/3. In the rabbit ear model, ATO prevented the progression of hypertrophic scar formation. CONCLUSIONS: This study provides the first evidence implying that ATO inhibits the formation of myofibroblasts in vivo and in vitro and provides a possible treatment for hypertrophic scars.

Induction of hepatocytes-derived insulin-producing cells using small molecules and identification of microRNA profiles during this procedure.

The transplantation of insulin-producing cells (IPCs) or pancreatic progenitor cells is a theoretical therapy for diabetes with insulin insufficiency. Isolated hepatocytes from newborn rats (within 24 h after birth) were progressively induced into IPCs using 5-aza-2'-deoxycytidine, Trichostatin A, retinoic acid, insulin-transferrin-selenium, and nicotinamide. We transplanted Pdx1+ pancreatic progenitors into STZ-induced diabetic mice and found the decreased blood glucose and increased insulin level in comparison with diabetic model. The dynamic expression profiles of microRNAs (miRNAs) were identified using microarray. We found 67 miRNAs were decreasingly expressed; 52 miRNAs were increasingly expressed; 27 miRNAs were specially inhibited in Stage 1 cells (multipotent progenitor cells); and 58 miRNAs were specially inhibited in Pdx1+ cells (Stage 2). Further analysis showed these miRNAs' targets were associated with genetic recombination, stem cell pluripotency maintenance, cellular structure reorganization and insulin secretion. Enrichment analysis using KEGG pathway showed the differentiation of IPCs from hepatocytes was massively more likely not mediated by canonical Wnt/ß-catenin signaling. In addition, the BMP/Smad signaling was involved in this progression. We found the dysregulated miRNAs profiles were inconsistent with cell phenotypes and might be responsible for small molecule-mediated cell differentiation during IPCs induction.