Characterization of Long Non-coding RNAs Modified by m6A RNA Methylation in Skeletal Myogenesis.

Proper development of mammalian skeletal muscle relies on precise gene expression regulation. Our previous studies revealed that muscle development is regulated by both mRNA and long non-coding RNAs (lncRNAs). Accumulating evidence has demonstrated that N6-methyladenosine (m6A) plays important roles in various biological processes, making it essential to profile m6A modification on a transcriptome-wide scale in developing muscle. Patterns of m6A methylation in lncRNAs in developing muscle have not been uncovered. Here, we reveal differentially expressed lncRNAs and report temporal m6A methylation patterns in lncRNAs expressed in mouse myoblasts and myotubes by RNA-seq and methylated RNA immunoprecipitation (MeRIP) sequencing. Many lncRNAs exhibit temporal differential expression, and m6A-lncRNAs harbor the consensus m6A motif "DRACH" along lncRNA transcripts. Interestingly, we found that m6A methylation levels of lncRNAs are positively correlated with the transcript abundance of lncRNAs. Overexpression or knockdown of m6A methyltransferase METTL3 alters the expression levels of these lncRNAs. Furthermore, we highlight that the function of m6A genic lncRNAs might correlate to their nearby mRNAs. Our work reveals a fundamental expression reference of m6A-mediated epitranscriptomic modifications in lncRNAs that are temporally expressed in developing muscle.

Dynamic m6A mRNA Methylation Reveals the Role of METTL3/14-m6A-MNK2-ERK Signaling Axis in Skeletal Muscle Differentiation and Regeneration.

N6-methyladenosine (m6A) RNA methylation has emerged as an important factor in various biological processes by regulating gene expression. However, the dynamic profile, function and underlying molecular mechanism of m6A modification during skeletal myogenesis remain elusive. Here, we report that members of the m6A core methyltransferase complex, METTL3 and METTL14, are downregulated during skeletal muscle development. Overexpression of either METTL3 or METTL14 dramatically blocks myotubes formation. Correspondingly, knockdown of METTL3 or METTL14 accelerates the differentiation of skeletal muscle cells. Genome-wide transcriptome analysis suggests ERK/MAPK is the downstream signaling pathway that is regulated to the greatest extent by METTL3/METTL14. Indeed, METTL3/METTL14 expression facilitates ERK/MAPK signaling. Via MeRIP-seq, we found that MNK2, a critical regulator of ERK/MAPK signaling, is m6A modified and is a direct target of METTL3/METTL14. We further revealed that YTHDF1 is a potential reader of m6A on MNK2, regulating MNK2 protein levels without affecting mRNA levels. Furthermore, we discovered that METTL3/14-MNK2 axis was up-regulated notably after acute skeletal muscle injury. Collectively, our studies revealed that the m6A writers METTL3/METTL14 and the m6A reader YTHDF1 orchestrate MNK2 expression posttranscriptionally and thus control ERK signaling, which is required for the maintenance of muscle myogenesis and may contribute to regeneration.

[Source Apportionment of Soil PAHs in Lanzhou Based on GIS and APCS-MLR Model].

To evaluate the pollution by polycyclic aromatic hydrocarbons (PAHs) in the surface soil of the core urban area of Lanzhou, 62 topsoil samples were collected from the area. The soil samples were analyzed for the content of 16 priority PAHs, using gas chromatography-mass spectrometry. Descriptive statistical methods were used to characterize contamination by PAHs. An absolute principal component analysis-multiple linear regression (APCS-MLR) model was applied to determine the sources of PAHs in the soil samples, and the accuracy of the model results was verified. Finally, the main influence regions of each source were determined with a geo-statistical method. The results showed that the contents of Σ16 PAHs in the surface soils of Lanzhou ranged from 1069 to 7377 µg ·kg-1, with an average of 2423 µg ·kg-1. High molecular weight PAHs (4-6 rings) were dominant, accounting for 72.81% of the Σ16 PAHs. Verification results of the APCS-MLR model showed that the measured values were in good correspondence with the predicted values, which indicated that the model had good applicability for source apportionment of soil PAHs in the study area. The main sources of PAHs in Lanzhou were traffic emissions (35.42%), petroleum emissions (29.88%), and a mixture of coal and biomass combustion (33.91%). The sources were greatly affected by human activities, and high values were mainly distributed in traffic-intensive and industrial areas. The results indicated that the sources of soil PAHs were complex and influenced by anthropogenic activities in the study area. Stringent control measures should be placed on the sources and areas of influence that contribute to soil PAHs to reduce the emissions and the level of soil pollution resulting from PAHs.

Oral P. gingivalis impairs gut permeability and mediates immune responses associated with neurodegeneration in LRRK2 R1441G mice.

BACKGROUND: The R1441G mutation in the leucine-rich repeat kinase 2 (LRRK2) gene results in late-onset Parkinson's disease (PD). Peripheral inflammation and gut microbiota are closely associated with the pathogenesis of PD. Chronic periodontitis is a common type of peripheral inflammation, which is associated with PD. Porphyromonas gingivalis (Pg), the most common bacterium causing chronic periodontitis, can cause alteration of gut microbiota. It is not known whether Pg-induced dysbiosis plays a role in the pathophysiology of PD. METHODS: In this study, live Pg were orally administrated to animals, three times a week for 1 month. Pg-derived lipopolysaccharide (LPS) was used to stimulate mononuclear cells in vitro. The effects of oral Pg administration on the gut and brain were evaluated through behaviors, morphology, and cytokine expression. RESULTS: Dopaminergic neurons in the substantia nigra were reduced, and activated microglial cells were increased in R1441G mice given oral Pg. In addition, an increase in mRNA expression of tumor necrosis factor (TNF-α) and interleukin-1ß (IL-1ß) as well as protein level of α-synuclein together with a decrease in zonula occludens-1 (Zo-1) was detected in the colon in Pg-treated R1441G mice. Furthermore, serum interleukin-17A (IL-17A) and brain IL-17 receptor A (IL-17RA) were increased in Pg-treated R1441G mice. CONCLUSIONS: These findings suggest that oral Pg-induced inflammation may play an important role in the pathophysiology of LRRK2-associated PD.

Allogeneic bone marrow-derived mesenchymal stromal cells for hepatitis B virus-related acute-on-chronic liver failure: A randomized controlled trial.

Mortality from hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF) is high due to limited treatment options. Preclinical and clinical investigations have proved that treatment with mesenchymal stromal cells (MSCs) is beneficial for recovery from liver injury. We hypothesized that the outcome of HBV-related ACLF would be improved by MSC treatment. From 2010 to 2013, 110 patients with HBV-related ACLF were enrolled in this open-label, nonblinded randomized controlled study. The control group (n = 54) was treated with standard medical therapy (SMT) only. The experimental group (n = 56) was infused weekly for 4 weeks with 1.0 to 10 × 105 cells/kg allogeneic bone marrow-derived MSCs and then followed for 24 weeks. The cumulated survival rate of the MSC group was 73.2% (95% confidence interval 61.6%-84.8%) versus 55.6% (95% confidence interval 42.3%-68.9%) for the SMT group (P = 0.03). There were no infusion-related side effects, but fever was more frequent in MSC compared to SMT patients during weeks 5-24 of follow-up. No carcinoma occurred in any trial patient in either group. Compared with the control group, allogeneic bone marrow-derived MSC treatment markedly improved clinical laboratory measurements, including serum total bilirubin and Model for End-Stage Liver Disease scores. The incidence of severe infection in the MSC group was much lower than that in the SMT group (16.1% versus 33.3%, P = 0.04). Mortality from multiple organ failure and severe infection was higher in the SMT group than in the MSC group (37.0% versus 17.9%, P = 0.02). CONCLUSION: Peripheral infusion of allogeneic bone marrow-derived MSCs is safe and convenient for patients with HBV-related ACLF and significantly increases the 24-week survival rate by improving liver function and decreasing the incidence of severe infections. (Hepatology 2017;66:209-219).

Low-dose tacrolimus combined with donor-derived mesenchymal stem cells after renal transplantation: a prospective, non-randomized study.

Calcineurin inhibitors, including tacrolimus, are largely responsible for advances in allotransplantation. However, the nephrotoxicity associated with these immunosuppressants impairs patients' long-term survival after renal allograft. Therefore, novel regimens that minimize or even eliminate calcineurin inhibitors could improve transplantation outcomes. In this pilot study, we investigated the use of low-dose tacrolimus in combination with mesenchymal stem cells (MSCs), which are immunosuppressive and prolong allograft survival in experimental organ transplant models. Donor-derived, bone marrow MSCs combined with a sparing dose of tacrolimus (0.04-0.05 mg/kg/day) were administered to 16 de novo living-related kidney transplant recipients; 16 other patients received a standard dose of tacrolimus (0.07-0.08 mg/kg/day). The safety of MSC infusion, acute rejection, graft function, graft survival, and patient survival were evaluated over ≥24 months following kidney transplantation. All patients survived and had stable renal function at the 24 month follow-up. The combination of low-dose tacrolimus and MSCs was as effective as standard dose tacrolimus in maintaining graft survival at least 2 years after transplantation. In addition, both groups had similar urea, urine protein, urinary RBC, urinary WBC, 24-h urine protein, and creatinine clearance rates from 7 days to 24 months after transplantation. Furthermore, no differences in the proportion of lymphocytes, CD19, CD3, CD34, CD38, and natural killer cells were detected between the control and experimental groups. None of the MSC recipients experienced immediate or long-term toxicity from the treatment. This preliminary data suggests that the addition of MSCs permits the use of lower dosages of nephrotoxic calcineurin inhibitors following renal transplantation.

[Clinical observation of mesenchymal stem cell as salvage treatment for refractory acute graft-versus-host disease].

OBJECTIVE: To explore the effect of mesenchymal stem cells (MSCs) on refractory acute graft-versus-host disease (GVHD) failed to second-line immunosuppressive therapy. METHODS: Twenty-two patients with refractory aGVHD received the treatment of first- and/or second-line immunosuppressive agents in combination with MSCs. The MSCs from bone marrow (BM) of HLA-unrelated third-party donors, were used at the median time of 19 (11 - 49) days after aGVHD onset, at a dose of 1×10(6)/kg once with an interval of 14 days. If the symptoms of aGVHD did not improve after continuous infusion four times, MSCs would be discontinued. Meanwhile the proportion of CD3(+)CD4(+), CD3(+)CD8(+) and CD4(+)CD25(+) was detected by flow cytometry (FCM) before and 4 weeks after the MSCs infusion. RESULTS: The median dose of MSC was 4.8 (2.5 - 6.3)×10(6) cell×kg(-1) with a median infusion of 2.5 (1 - 7) times per case. Twelve patients achieved complete response (CR), four partial response (PR) after treatment. The total effective rate was 72.7% (16/22). With a median follow-up of 246.5 (36 - 1116) days post-transplantation, 11 patients survived and 11 died. The causes of death included GVHD(n = 6), infections (n = 3), leukemia relapse (n = 1) and post-transplant lymphoproliferative diseases (n = 1), respectively. The proportion of CD3(+)CD4(+)/CD3(+)CD8(+) was significantly higher at 4th week after MSCs infusion compared to before infusion (1.58 ± 0.54 vs 0.49 ± 0.19, \%t\% = 0.628, P = 0.04). The number of CD4(+)CD25(+) Treg cells had not changed much compared to before infusion (P = 0.606). CONCLUSION: MSCs derived from the BM of a third-party donor are effective to treat aGVHD failed to second-line immunosuppressive therapy after allo-HSCT. MSCs might play a role in aGVHD by regulating the rate of CD3(+)CD4(+)/CD3(+)CD8(+).

[The outcome and safety of mesenchymal stem cells from bone marrow of a third party donor in treatment of secondary poor graft function following allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To evaluate the efficacy and safety of bone marrow-derived mesenchymal stem cells (MSC) from a third party donor for secondary poor graft function (PGF) following allogeneic hematopoietic stem cell transplantation(allo-HSCT). METHODS: Five patients with secondary PGF were treated with MSC at a dose of 1 x 10(6)/kg body weight at a median of 47 days (35 to 61) after secondary PGF. MSC were derived from bone marrow (BM) of HLA-disparate third party donors, cultured in vitro and infused without HSC. If absolute neutrophil cell (ANC) and platelet counts (PLT) did not reach the standardization of > 1.5 x 10(9)/L and > 50.0 x 10(9)/L, respectively, within 28-30 days after the first MSC treatment, a second MSC treatment was required. RESULTS: MSC were infused once in one patient and twice in four patients with an interval of 28 to 30 days. All patients obtained ANC and PLT recovery at a median of 34 (25 to 49) days and 47 (26 to 54) days, respectively, without toxic side effects within follow-up periods of median 761 (204-1491) days. Three patients developed Epstein-Barr virus (EBV) reactivation at 42, 48, 108 days after MSC infusion, respectively and two of the three coverted to posttransplant lymphoproliferative disorders (PTLD). CONCLUSION: MSC from a third party donor are effective to patients with secondary PGF following allo-HSCT, whether it might increase the risk of EBV reactivation and EBV-associated PTLD need further observation.

[Study of relationship between cyclooxygenase and platelet-activating factor on peripheral blood mononuclear cells in patients with systemic inflammatory response syndrome and multiple organ dysfunction syndrome].

OBJECTIVE: To study the role of cyclooxygenase (COX) and platelet-activating factor (PAF) in pathophysiologic mechanisms of patients with systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). METHODS: Twenty-eight adult patients whose diagnosis met American college of chest physicians/society of critical care medicine (ACCP/SCCM) criteria for SIRS and MODS were enrolled for study including 13 cases for SIRS group and 15 cases for MODS group. The normal control group consisted of 11 healthy volunteers who matched with study subjects for age and gender. Enzyme linked immunoadsorbent assay (ELISA) was used to measure the content of COX-2 and the activity of platelet-activating factor acetylhydrolase (PAF-AH) of peripheral blood mononuclear cells (PBMCs). Reverse transcription polymerase chain reaction (RT-PCR) was used to measure the COX-2 mRNA and PAF-AH mRNA expression of PBMCs. RESULTS: The content of COX-2 and the activity of PAF-AH of PBMCs and the expression of their mRNA in MODS group were higher than those in SIRS group and control group (all P<0.05). There was no significant difference between SIRS group and control group. The content of COX-2 and the activity of PAF-AH and the expression of their mRNA of PBMCs in non-survivors were higher than those in survived patients (all P<0.05). In 3 groups, positive correlation was found between the COX-2 content and PAF-AH activity (r=0.329, P<0.05). The leukocyte count, lymphocyte count, and PaO(2)/FiO(2) of peripheral blood in non-survivors showed no significant difference with those of survived patients (all P>0.05). The blood glucose and creatinine of non-survivors were higher than those of survived patients (P<0.05 and P<0.01). The total CO(2) content (TCO(2)) and pH value of non-survivors were lower than those of survived patients (both P<0.01). CONCLUSION: This study shows that COX-2 and PAF-AH play a role in the occurrence of MODS and they can be used as indexes to judge the prognosis of SIRS and MODS. Blood glucose, creatinine, TCO(2) and pH value of blood can be used as other indexes for judging the state and the prognosis of the illness.