iMyoblasts for ex vivo and in vivo investigations of human myogenesis and disease modeling

Skeletal muscle myoblasts (iMyoblasts) were generated from human induced pluripotent stem cells (iPSCs) using an efficient and reliable transgene-free induction and stem cell selection protocol. Immunofluorescence, flow cytometry, qPCR, digital RNA expression profiling, and scRNA-Seq studies identify iMyoblasts as a PAX3+/MYOD1+ skeletal myogenic lineage with a fetal-like transcriptome signature, distinct from adult muscle biopsy myoblasts (bMyoblasts) and iPSC-induced muscle progenitors. iMyoblasts can be stably propagated for >12 passages or 30 population doublings while retaining their dual commitment for myotube differentiation and regeneration of reserve cells. iMyoblasts also efficiently xenoengrafted into irradiated and injured mouse muscle where they undergo differentiation and fetal-adult MYH isoform switching, demonstrating their regulatory plasticity for adult muscle maturation in response to signals in the host muscle. Xenograft muscle retains PAX3+ muscle progenitors and can regenerate human muscle in response to secondary injury. As models of disease, iMyoblasts from individuals with Facioscapulohumeral Muscular Dystrophy revealed a previously unknown epigenetic regulatory mechanism controlling developmental expression of the pathological DUX4 gene. iMyoblasts from Limb-Girdle Muscular Dystrophy R7 and R9 and Walker Warburg Syndrome patients modeled their molecular disease pathologies and were responsive to small molecule and gene editing therapeutics. These findings establish the utility of iMyoblasts for ex vivo and in vivo investigations of human myogenesis and disease pathogenesis and for the development of muscle stem cell therapeutics.

Two new polycyclic polyprenylated acylphloroglucinols derivatives from Hypericum acmosepalum

Polycyclic polyprenylated acylphloroglucinols (PPAPs) were mainly obtained from the plants of Hypericum genus of Guttiferae family, and possessed intriguing chemical structures and appealing biological activities. Two new PPAPs derivatives, hyperacmosin C (1) and hyperacmosin D (2) were isolated from H. acmosepalum. Their structures were established by NMR, HREIMS, and experimental electronic circular dichroism spectra. Besides, compound 1 showed significant hepatoprotective activity at 10 µM against paracetamol-induced HepG2 cell damage and compound 2 could moderately increase the relative glucose consumption.

[The influencing factors achieving target vancomycin trough level in critically ill patients]

Objective: To assess the rate achieving the target vancomycin trough level (VTL) and its influencing factors in critically ill patients. Methods: The retrospective observational study recruited adult patients treated with intravenous vancomycin in the intensive care unit (ICU) at Zhongda Hospital from January 2015 to December 2017. Serum VTL was tested at steady state. Patients' demographics, the sites of infection, microbial culture results, the severity of illness, laboratory data and vancomycin regimen were obtained at the baseline. The rate achieving target VTL (15-20 mg/L) was analyzed based on renal function. Linear regression was performed to determine the influencing factors of VTL. Results: A total of 85 patients were enrolled, among whom only 23.5% (20/85) achieved the target VTL. In patients with normal renal function, the achieving rate was only 11.4% (4/35), and 80.0% (28/35) was lower than the target trough level multiple linear regression analysis showed that procalcitonin (PCT), estimated glomerular filtration rate (eGFR) and acute physiology and chronic health disease classification system Ⅱ (APACHE Ⅱ) score were independent factors associated with VTL. Conclusion: Achieving target VTL in critically ill patients is not satisfactory. Further study to optimize the administration is needed to facilitate prompt attainment of target VTL.

Hyperascyrins L - N, rare methylated polycyclic polyprenylated acylphloroglucinol derivatives from Hypericum ascyron

Seven natural compounds, including new compounds hyperascyrins L-N (1-3) and four known compounds (4-7), were acquired from the aerial parts of Hypericum ascyron, that were all identified as methylated polycyclic polyprenylated acylphloroglucinol derivatives (mPPAPs). The structures of these compounds were established by NMR spectroscopy, experimental and calculated electronic circular dichroism (ECD) data. The neuroprotective activities and hepatoprotective activity of these compounds (10 µM) were evaluated. Compounds 1, 2 and 3 exhibited neuroprotection activity. Compounds 1 and 3 show hepatoprotective activity.

Methylated Polycyclic Polyprenylated Acylphloroglucinol Derivatives from Hypericum ascyron

Hyperascyrins A-H (1-11) and four known compounds (12-15) were acquired from the air-dried aerial parts of Hypericum ascyron and were all identified as methylated polycyclic polyprenylated acylphloroglucinol derivatives. Their structures were established by NMR spectroscopy, experimental and calculated electronic circular dichroism (ECD) data, and comparison with established compounds. Compounds 8 and 9 showed protection against paracetamol-induced HepG2 cell damage at 10 μM. The neuroprotective activities of all compounds (10 μM) were evaluated, and compounds 1 and 8 exhibited mild neuroprotection against glutamate-induced toxicity in SK-N-SH cells.

[Chemical constituents of Hypericum perforatum]

A chemical investigation on the aerial parts of Hypericum perforatum resulted in the isolation of a new phloroglucinol derivatives (1), and seven known compounds (2-8). The structures of the compounds were elucidated by means of spectroscopic methods (MS, IR, 1D NMR, and 2D NMR) as 3-methyl-4,6-di (3- methyl-2-butenyl)-3-(4-methyl-3-pentenyl)-2-(2-ethyl-1-oxobutyl)-cyclohexanone (1)，hyperforin (2)，(2R,3R,4S,6R)-3-methyl-4,6-di(3-methyl-2-butenyl)-2-(2-methyl-1-oxo-propyl)-3-(4-methyl-3-pentenyl)-cyclohexanone (3)，hyperscabrin B (4)，hyperscabrin C (5)，furohyperforin isomer 1 (6)，furoadhyperforin (7)，and furohyperforin (8). Compound 1 was a new compound, and compounds 3-5 were obtained from H. perforatum for the first time.

Synthesis and antitumor activities of sinomenine derivatives on rings A and C

A series of new sinomenine derivatives were designed, synthesized, and evaluated in tumor inhibitory activity, such as human triple negative breast cancer cell line (MDA-MB-231), glioma cell line (A172), human lung cancer cell line (A549), human colon cancer cell line (HCT-8). The modifications were carried out on rings A and C of the sinomenine by esterificating on phenolic hydroxyl with good yields. The highlight of this work was that the synthetic procedures were concise and sinomenine derivatives demonstrated promising antitumor activities.

Emodin and baicalein inhibit sodium taurocholate-induced vacuole formation in pancreatic acinar cells

AIM

To investigate the effects of combined use of emodin and baicalein (CEB) at the cellular and organism levels in severe acute pancreatitis (SAP) and explore the underlying mechanism.

METHODS

SAP was induced by retrograde infusion of 5% sodium taurocholate into the pancreatic duct in 48 male SD rats. Pancreatic histopathology score, serum amylase activity, and levels of tumour necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and IL-10 were determined to assess the effects of CEB at 12 h after the surgery. The rat pancreatic acinar cells were isolated from healthy male SD rats using collagenase. The cell viability, cell ultrastructure, intracellular free Ca²⁺ concentration, and inositol (1,4,5)-trisphosphate receptor (IP₃R) expression were investigated to assess the mechanism of CEB.

RESULTS

Pancreatic histopathology score (2.07 ± 1.20 vs 6.84 ± 1.13, P < 0.05) and serum amylase activity (2866.2 ± 617.7 vs 5241.3 ± 1410.0, P < 0.05) were significantly decreased in the CEB (three doses) treatment group compared with the SAP group (2.07 ± 1.20 vs 6.84 ± 1.13, P < 0.05). CEB dose-dependently reduced the levels of the pro-inflammatory cytokines IL-6 (466.82 ± 48.55 vs 603.50 ± 75.53, P < 0.05) and TNF-α (108.04 ± 16.10 vs 215.56 ± 74.67, P < 0.05) and increased the level of the anti-inflammatory cytokine IL-10 (200.96 ± 50.76 vs 54.18 ± 6.07, P < 0.05) compared with those in the SAP group. CEB increased cell viability, inhibited cytosolic Ca²⁺ concentration, and significantly ameliorated intracellular vacuoles and IP₃ mRNA expression compared with those in the SAP group (P < 0.05). There was a trend towards decreased IP₃R protein in the CEB treatment group; however, it did not reach statistical significance (P > 0.05).

CONCLUSION

These results at the cellular and organism levels reflect a preliminary mechanism of CEB in SAP and indicate that CEB is a suitable approach for SAP treatment.

Functional cloning of IGFBP-3 from human microvascular endothelial cells reveals its novel role in promoting proliferation of primitive CD34+CD38- hematopoietic cells in vitro

Ex vivo expansion of hematopoietic stem cells (HSCs) has been investigated as a means of enhancing engraftment of transplantation therapies, but current ex vivo expansion methods typically result in a loss of functional stem cell activity. Factors that can selectively expand human HSCs remain elusive. Recently we have isolated three functionally distinct human brain microvascular endothelial cells (HBMVECs) that differ greatly in their ability to support in vitro proliferation of human umbilical cord blood (UBC) CD34+CD38-cells. Using these distinct HBMVEC populations, we have devised a cell-based functional cloning assay to identify a molecule(s) capable of facilitating expansion of HSCs in vitro. A gene encoded for IGFBP-3 (insulin-like growth factor binding protein-3) has been identified. IGFBP-3 mRNA and protein are differentially expressed in distinct HBMVEC populations. In vitro cell proliferation assay and CD34+CD38- immunophenotype analysis showed that the addition of an exogenous IGFBP-3 to cultures of purified CD34+/-CD38-Lin- cells (CD2/CD3/CD14/CD16/CD19/CD24/CD56/CD66b/GlyA depleted) enhanced proliferation of primitive hematopoietic cells with CD34+CD38- phenotype, suggesting that IGFBP-3 is capable of expanding primitive human blood cells. These expanded primitive blood cells were illustrated to maintain ability to generate functional progenitors. IGFBP-3 belongs to a family of high-affinity IGFBPs, which binds to IGFs and modulates their actions. IGFBP-3 appears to have intrinsic bioactivity that is independent of IGF binding. We are currently exploring the underlying mechanism by which IGFBP-3 modulates proliferation of primitive hematopoietic cells, and the potential of IGFBP-3 to expand pluripotent human repopulating cells capable of hematopoietic reconstitution of irradiated NOD/SCID recipients.

Roles of Ets proteins, NF-kappa B and nocodazole in regulating induction of transcription of mouse germline Ig alpha RNA by transforming growth factor-beta 1

Antibody class switch recombination (CSR) occurs after antigen activation of B cells. CSR is directed to specific heavy chain isotypes by cytokines and B cell activators that induce transcription from the unrearranged, or germline (GL), C(H) region genes. Transforming growth factor (TGF)-beta1 is essential for switch recombination to IgA due to its ability to induce transcription from GL Ig alpha genes. It has been shown that the promoters which regulate transcription of mouse and human GL alpha RNAs contain a TGF-beta1-responsive element that binds Smad and core binding factor (CBFalpha)/AML/PEBPalpha/RUNX: They also contain other elements which bind the transcription factors CREB, BSAP and Ets family proteins. In this manuscript we demonstrate that two tandem Ets sites in the mouse GL alpha promoter bind the transcription factors Elf-1 and PU.1, and that the 3' site is essential for expression of a luciferase reporter gene driven by the GL alpha promoter. Binding of Elf-1 to the GL alpha promoter is inducible by lipopolysaccharide in nuclear extracts from splenic B cells. An NF-kappaB site is identified, although it does not contribute to expression of the promoter in reporter gene assays. Since CSR to IgA is greatly reduced in NF-kappaB/p50-deficient mice, these data support the hypothesis that NF-kappaB has roles in switching in addition to regulation of GL transcription. Finally, we demonstrate that nocodazole, which disrupts microtubules that sequester Smad proteins in the cytoplasm, stimulates transcription from the GL alpha promoter.

[Effects of total flavones of metasequosia on left ventricular hypertrophy due to pressure overload in rats]

OBJECTIVE

To determine the preventive and regressive effects of total flavones of metasequosia (TFM) on left ventricular hypertrophy in rats.

METHOD

Left ventricular hypertrophy was inducedin by partial ligation of abdominal aorta. The rats were given ig TFM(4, 40, 400 mg.kg-1.d-1) for six weeks.

RESULT

TFM markedly reduced the HW/BW, LVW/BW, myofibril diameter and Ca2+ content in left ventricles but the systolic blood pressure (SBP) in rats wasn't obviously influenced.

CONCLUSION

TFM can prevent and reverse the left ventricular hypertrophy due to pressure overload in rats. The mechanism may be related to its calcium antagonistic properties.

Evidence for class-specific factors in immunoglobulin isotype switching

Immunoglobulin class switch recombination (SR) occurs by a B cell-specific, intrachromosomal deletional process between switch regions. We have developed a plasmid-based transient transfection assay for SR to test for the presence of transacting switch activities. The plasmids are novel in that they lack a eukaryotic origin of DNA replication. The recombination activity of these switch substrates is restricted to a subset of B cell lines that support isotype switching on their endogenous loci and to mitogen-activated normal splenic B cells. The factors required for extrachromosomal plasmid recombination are constitutively expressed in proliferating splenic B cells and in B cell lines capable of inducibly undergoing immunoglobulin SR on their chromosomal genes. These studies suggest that mitogens that induce switching on the chromosome induce accessibility rather than switch recombinase activity. Finally, we provide evidence for two distinct switching activities which independently mediate mu-->alpha and mu-->gamma3 SR.

Interaction and functional cooperation of PEBP2/CBF with Smads. Synergistic induction of the immunoglobulin germline Calpha promoter

Smads are signal transducers for members of the transforming growth factor-beta (TGF-beta) superfamily. Upon ligand stimulation, receptor-regulated Smads (R-Smads) are phosphorylated by serine/threonine kinase receptors, form complexes with common-partner Smad, and translocate into the nucleus, where they regulate the transcription of target genes together with other transcription factors. Polyomavirus enhancer binding protein 2/core binding factor (PEBP2/CBF) is a transcription factor complex composed of alpha and beta subunits. The alpha subunits of PEBP2/CBF, which contain the highly conserved Runt domain, play essential roles in hematopoiesis and osteogenesis. Here we show that three mammalian alpha subunits of PEBP2/CBF form complexes with R-Smads that act in TGF-beta/activin pathways as well as those acting in bone morphogenetic protein (BMP) pathways. Among them, PEBP2alphaC/CBFA3/AML2 forms a complex with Smad3 and stimulates transcription of the germline Ig Calpha promoter in a cooperative manner, for which binding of both factors to their specific binding sites is essential. PEBP2 may thus be a nuclear target of TGF-beta/BMP signaling.

CBFα3 (AML2) Is Induced by TGF-β1 to Bind and Activate the Mouse Germline Ig α Promoter

TGF-β1 directs class switching to IgA by splenic B cells and by the surface IgM+ B cell line, I.29μ, by inducing germline (GL) Ig α transcripts. The promoter segment between −130 and +46, relative to the first initiation site for mouse GL α transcripts, is sufficient for expression and TGF-β1 inducibility of a reporter gene in B cell lines. Within this segment resides a TGF-β1-responsive element (TβRE) that is required for induction of the promoter by TGF-β1 and, when multimerized, is sufficient to transfer TGF-β1 inducibility to another promoter. In this report we show that a TGF-β1-inducible complex binds the TβRE and contains the transcription factor core-binding factor (CBF; also known as acute myeloid leukemia, AML). Although all three CBFα family members activate the GL α promoter, only CBFα3 (AML-2) is induced by TGF-β1 in splenic B and I.29μ cells. The TβRE contains two CBF binding sites. Mutation of both sites reduces but does not eliminate induction of the GL α promoter by TGF-β1 or by overexpression of CBF, possibly due to the presence of an additional CBF site in the promoter. In addition, the TβRE contains two copies of another sequence motif. Mutation of these motifs eliminates TGF-β1 induction of the GL α promoter. Together the data indicate that TGF-β1 induction of the α promoter involves induction of CBFα3, which binds to the TβRE of the promoter along with one or more proteins.

CBF alpha3 (AML2) is induced by TGF-beta1 to bind and activate the mouse germline Ig alpha promoter

TGF-beta1 directs class switching to IgA by splenic B cells and by the surface IgM+ B cell line, I.29mu, by inducing germline (GL) Ig alpha transcripts. The promoter segment between -130 and +46, relative to the first initiation site for mouse GL alpha transcripts, is sufficient for expression and TGF-beta1 inducibility of a reporter gene in B cell lines. Within this segment resides a TGF-beta1-responsive element (TbetaRE) that is required for induction of the promoter by TGF-beta1 and, when multimerized, is sufficient to transfer TGF-beta1 inducibility to another promoter. In this report we show that a TGF-beta1-inducible complex binds the TbetaRE and contains the transcription factor core-binding factor (CBF; also known as acute myeloid leukemia, AML). Although all three CBF alpha family members activate the GL alpha promoter, only CBF alpha3 (AML-2) is induced by TGF-beta1 in splenic B and I.29mu cells. The TbetaRE contains two CBF binding sites. Mutation of both sites reduces but does not eliminate induction of the GL alpha promoter by TGF-beta1 or by overexpression of CBF, possibly due to the presence of an additional CBF site in the promoter. In addition, the TbetaRE contains two copies of another sequence motif. Mutation of these motifs eliminates TGF-beta1 induction of the GL alpha promoter. Together the data indicate that TGF-beta1 induction of the alpha promoter involves induction of CBF alpha3, which binds to the TbetaRE of the promoter along with one or more proteins.

[Effect of intestinal lymph on blood pressure of rat]

The effect of intestinal lymph on blood pressure in rats was observed by the methods of lymph drainage and lymph infusion. The results obtained are as follows: (1) After 150 min of the lymph drained through the cannula of intestinal lymph duct, the blood pressure was significantly lower than that of the sham group (P < 0.05). (2) Equivalent albumin or intralipid infusion was not able to prevent the decrease in blood pressure when the lymph was lost. But in jugular-intestinal lymph duct shunt group, no significant blood pressure decrease could be seen during the drainage procedure for 4 h. (3) The blood pressure of rat with serious hemorrhagic shock could be increased significantly with a little amount of intestinal lymph infusion, and the rats survived longer than those of the control group (P < 0.05-0.01). The above results suggest that the intestinal lymph may play an important role in maintenance of blood pressure, in addition to the known function of lymphatic system by returning tissue fluid to blood and maintaining circulating blood volume.