GDF11 slows excitatory neuronal senescence and brain ageing by repressing p21.

As a major neuron type in the brain, the excitatory neuron (EN) regulates the lifespan in C. elegans. How the EN acquires senescence, however, is unknown. Here, we show that growth differentiation factor 11 (GDF11) is predominantly expressed in the EN in the adult mouse, marmoset and human brain. In mice, selective knock-out of GDF11 in the post-mitotic EN shapes the brain ageing-related transcriptional profile, induces EN senescence and hyperexcitability, prunes their dendrites, impedes their synaptic input, impairs object recognition memory and shortens the lifespan, establishing a functional link between GDF11, brain ageing and cognition. In vitro GDF11 deletion causes cellular senescence in Neuro-2a cells. Mechanistically, GDF11 deletion induces neuronal senescence via Smad2-induced transcription of the pro-senescence factor p21. This work indicates that endogenous GDF11 acts as a brake on EN senescence and brain ageing.

Inhibition of RIPK1 by ZJU-37 promotes oligodendrocyte progenitor proliferation and remyelination via NF-κB pathway.

Receptor interacting serine/threonine protein kinase 1 (RIPK1) activation and necroptosis have been genetically and mechanistically linked with human multiple sclerosis and neurodegenerative diseases for which demyelination is a common key pathology. Demyelination can be healed through remyelination which is mediated by new oligodendrocytes derived from the adult oligodendrocyte progenitor cells (OPCs). Unfortunately, the efficiency of remyelination declines with progressive aging partially due to the depletion of OPCs following chronic or repeated demyelination. However, to our knowledge, so far there is no drug which enhances proliferation of OPCs, and it is unknown whether inhibiting RIPK1 activity directly affect OPCs, the central player of remyelination. Using TNFα induced RIPK1-dependent necroptosis in Jurkat FADD-/- cells as a cell death assay, we screened from 2112 FDA-approved drugs and the drug candidates of new RIPK1 inhibitors selected by ourselves, and identified ZJU-37, a small molecule modified by introducing an amide bond to Nec-1s, is a new RIPK1 kinase inhibitor with higher potency than Nec-1s which has the best reported potency. We unveil in addition to protecting myelin from demyelination and axons from degeneration, ZJU-37 exhibits a new role on promoting proliferation of OPCs and enhancing remyelination by inhibiting RIPK1 kinase activity with higher potency than Nec-1s. Mechanistically, ZJU-37 promotes proliferation of OPCs by enhancing the transcription of platelet derived growth factor receptor alpha via NF-κB pathway. This work identifies ZJU-37 as a new drug candidate which enhances remyelination by promoting proliferation of OPCs, paving the way for a potential drug to enhance myelin repair.

Restoring nuclear entry of Sirtuin 2 in oligodendrocyte progenitor cells promotes remyelination during ageing.

The age-dependent decline in remyelination potential of the central nervous system during ageing is associated with a declined differentiation capacity of oligodendrocyte progenitor cells (OPCs). The molecular players that can enhance OPC differentiation or rejuvenate OPCs are unclear. Here we show that, in mouse OPCs, nuclear entry of SIRT2 is impaired and NAD+ levels are reduced during ageing. When we supplement ß-nicotinamide mononucleotide (ß-NMN), an NAD+ precursor, nuclear entry of SIRT2 in OPCs, OPC differentiation, and remyelination were rescued in aged animals. We show that the effects on myelination are mediated via the NAD+-SIRT2-H3K18Ac-ID4 axis, and SIRT2 is required for rejuvenating OPCs. Our results show that SIRT2 and NAD+ levels rescue the aged OPC differentiation potential to levels comparable to young age, providing potential targets to enhance remyelination during ageing.

Neutralization of Hv1/HVCN1 With Antibody Enhances Microglia/Macrophages Myelin Clearance by Promoting Their Migration in the Brain.

Microglia dynamically monitor the microenvironment of the central nervous system (CNS) by constantly extending and retracting their processes in physiological conditions, and microglia/macrophages rapidly migrate into lesion sites in response to injuries or diseases in the CNS. Consequently, their migration ability is fundamentally important for their proper functioning. However, the mechanisms underlying their migration have not been fully understood. We wonder whether the voltage-gated proton channel HVCN1 in microglia/macrophages in the brain plays a role in their migration. We show in this study that in physiological conditions, microglia and bone marrow derived macrophage (BMDM) express HVCN1 with the highest level among glial cells, and upregulation of HVCN1 in microglia/macrophages is presented in multiple injuries and diseases of the CNS, reflecting the overactivation of HVCN1. In parallel, myelin debris accumulation occurs in both the focal lesion and the site where neurodegeneration takes place. Importantly, both genetic deletion of the HVCN1 gene in cells in vitro and neutralization of HVCN1 with antibody in the brain in vivo promotes migration of microglia/macrophages. Furthermore, neutralization of HVCN1 with antibody in the brain in vivo promotes myelin debris clearance by microglia/macrophages. This study uncovers a new role of HVCN1 in microglia/macrophages, coupling the proton channel HVCN1 to the migration of microglia/macrophages for the first time.

[Effect of processing excipient suet oil on formation and absorption of baohuoside â -bile salt self-assembled micelles].

The fried method with suet oil,which can strengthen the effect of Epimedium in warming kidney and enhancing Yang,has been widely used in the processing of Epimedium in traditional Chinese medicine. Based on the formation mechanism of Epimedium flavonoids self-assembled micelles in vivo,the synergistic mechanism of processing excipient suet oil was investigated in this paper from the perspective of pharmaceutics. Baohuoside Ⅰ,as representative component of processed Epimedium,was selected as model drug.Average size and zeta potential were measured and the morphology of micelles was observed under transmission electron microscopy. Caco-2 monolayer cell model,rat intestinal perfusion model and in vivo serum drug concentration method were established to investigate the effect of suet oil on the formation and absorption of the baohuosideⅠ bile salt self-assembled micelles. Baohuoside Ⅰ can form selfassembled micelles under the action of sodium deoxycholate. While,adding suet oil into the baohuoside Ⅰ-bile salt micelles( BSDOC) can make it form a more stable system with a smaller average size,higher Zeta potential,lower polydispersity index( PDI) value,significantly improved encapsulation efficiency and drug loading,indicating that suet oil could significantly improve the micelle formation in vivo. In addition,the permeability coefficient of baohuoside Ⅰ in Caco-2 monolayer cells and the four intestinal organs( duodenum,jejunum,ileum and colon) was increased and the oral bioavailability was also improved after adding the suet oil to BS-DOC.All the results demonstrated that the suet oil can promote the formation and absorption of baohuoside Ⅰ self-assembled micelles,so as to enhance its synergistic effects.

[Mechanism of flavonoid components in Astragali Radix in inhibiting tumor growth and immunoregulation in C57BL/6 tumor bearing mice based on "invigorating Qi for consolidation of exterior"].

Traditional Chinese medicine believes that the occurrence and development of tumors is related to the body's Qi deficiency. " Invigorating Qi for consolidation of exterior" has became an effective way to treat tumors by traditional Chinese medicine. This study is based on the " invigorating Qi for consolidation of exterior" to explore the effect of flavonoid components in Qi-invigorating herbs Astragali Radix( AR) on the growth and immune function of mouse Lewis lung cancer xenografts,and further explore its mechanism of action. In the present study,high performance liquid chromatography was performed to analyze the flavonoid components in AR.The Lewis lung cancer model of C57 BL/6 mice was constructed,and the tumor volume of mice was determined by Visual Sonics Vevo2100 high frequency color ultrasound. The levels of IL~(-1)7 and RORγt in serum and tumor tissues were detected by ELISA and immunohistochemistry. The expression of IRE~(-1)/XBP~(-1) pathway-related proteins in tumor tissues was detected by Western blot. The results revealed that treatment of 5 and 10 g·kg~(-1)·d~(-1) of flavonoid components in AR significantly inhibited tumor growth of C57 BL/6 tumorbearing mice. The inhibition rates at the dose of 5 and 10 g·kg~(-1)·d~(-1) of flavonoid components in AR were( 29. 5±4. 4) % and( 43. 4±5. 2) %,respectively. The expression of IL~(-1)7 and RORγt in serum and tumor tissues of Lewis lung cancer mice were decreased,and the spleen index and thymus index were significantly enhanced by the flavonoid components in AR. Flavonoid components in AR could decrease the expression of X-box binding protein 1( XBP1),inositol-requiring enzyme( IRE1) and glucose regulated protein 78 k D( GRP78),and increase the expression of C/EBP homologous protein( CHOP),and the high-dose group is better,suggesting that the anti-lung cancer effect of flavonoid components in AR is related to the regulation of XBP1 mediated ERs. This study provides new evidence that the flavonoid components in AR could inhibit the tumor growth of C57 BL/6 tumor-bearing mice by regulating the body's immune function through " invigorating Qi for consolidation of exterior".

[Responses of main characters of root system to salt stress among cotton varieties with diffe-rent salt tolerance]. / ä¸åŒè€ç›å“ç§æ£‰èŠ±æ ¹ç³»ä¸»è¦æŒ‡æ ‡å¯¹ç›åˆ†èƒè¿«çš„å“åº”.

A pot experiment was carried out to test the effects of salt levels on root morphology as well as the relationship between root morphology and salt tolerance with four cotton cultivars (salt-sensitive cultivar CCRI45, weak salt-resistance cultivar XLZ17, moderate salt-resistance cultivar XLZ13 and salt-resistance cultivar CCRI35). Results showed that dry mass and K+/Na+ ratio of cotton root and leaf were significantly reduced by salt stress. Dry mass of root and leaf and K+/Na+ ratio of root of cultivars XLZ13 and CCRI35 were 69.3%-104.4%, 24.8%-45.3% and 25.0%-45.8% higher than those of cultivar CCRI45, respectively. Root development was significantly restrained by salt stress. Total root length, total root surface area and total root volume of cultivars XLZ13 and CCRI35 were 15.2%-85.8%, 12.0%-68.5% and 31.7%-217.8% higher than those of cultivar CCRI45, respectively. Furthermore, the length of fine and middle roots, root surface area and root volume of cultivars XLZ13 and CCRI35 in 0-10 cm soil layer were 27.2%-73.9%, 39.6%-74.3% and 99.0%-309.7% higher than those of cultivar CCRI45, respectively. Results from principal component analysis showed that the variations of specific root length, root length ratio at 0-10 cm soil layer and fine root length ratio at 0-10 cm soil layer among cultivars was significant. Specific root length, root length ratio at 0-10 cm soil layer and fine root length ratio at 0-10 cm soil layer were the main root characters to distinguish different salt tolerant cotton cultivars. Results from the stepwise regression analysis showed that specific root length, coarse root length, coarse root area, and coarse root volume at 0-10 cm and 10-20 cm soil layers, as well as fine root area and middle root ratio at 0-10 cm soil layer were sensitive to salt. Salt tolerant cultivar adapted to salt stress through increasing root length ratio, fine length ratio, and specific root length.

[A study of tracking the superparamagnetic iron oxide and enhanced green fluorescent protein labeled miniature porcine bone marrow stem cells by in vitro MRI].

OBJECTIVES: To track bone marrow stem cells (BMSCs) labeled by enhanced green fluorescent protein (EGFP) and superparamagnetic iron oxide (SPIO)-poly-L-lysine (PLL) compound by MRI in vitro for autotransplantation into pancreas of type 1 diabetes miniature pigs. METHODS: The BMSCs were isolated by density gradient centrifugation and attachment culture from type 1 diabetes minipigs' bone marrow. Expressional intensity of EGFP in BMSCs transfected lentivirus-EGFP with a multiplicity of infection (MOI) of 30:1 reached the highest level after 96 h from transfection, while the positive rate was 43.2%. Different magnetic resonance scanning protocols were carried out on various density BMSCs labeled by different concentration of SPIO in various time-point in vitro. RESULTS: When SPIO concentration was 25 mg/L (count in Fe(3+)), the positive Fe(3+)-labeling rate of BMSCs was 93.1%. Most of SPIO particles in BMSCs' cytoplasm were observed in secondary lysosomes, but they were not detected in important organelle as cell nucleus. Comparing with gelatin the MRI of BMSCs labeled with SPIO in the condition with 1 × 10(4)/ml cells density and 25 mg/L Fe(3+) concentration in vitro, the signal intensity changes (ΔSI) after BMSCs labeled with SPIO 3 weeks and 6 weeks in TSE T(1)WI, TSE T(2)WI and FLASH T(2) WI sequences were 12%, 41%, 63% and 7%, 28%, 46% respectively (P < 0.01 and P < 0.05, respectively). CONCLUSIONS: The data showed that the porcine BMSCs labeled with SPIO and EGFP could be traced successfully in vitro by MRI in the suitable sequences.

[Pathology and molecular pathogenesis of spondyloepiphyseal dysplasia tarda with progressive arthropathy caused by compound CCN6 heterogeneous gene mutations].

OBJECTIVE: To characterize the clinical manifestations, features of roentgenography and MR imaging, and the pathology of articular cartilage and matrix of spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA), to screen the mutations of the disease-causing CCN6 gene, and try to elucidate the molecular pathogenesis of SEDT-PA. METHODS: A questionnaire survey on the clinical manifestations and history was conducted among a pedigree of SEDT-PA with 57 persons (53 living members) in tolal, including 2 probands, a 19-year old female and a 9-year old male. Physical examination and roentgenography and MR imaging were used on the 2 probands to characterize the features of their joints and articular cartilage. The femoral head extracted during replacement of hip of the proband 1 underwent hematoxylin-eosin staining and toludine blue (TB) staining to observe the pathological changes and ultra-microstructure of the articular chondrocytes and cartilage matrix using electron microscopy. Peripheral blood samples were collected from these 53 living members and 100 healthy controls. PCR was used to examine and sequence the exons of CCN6. 3D-conformational illustration of mutant CCN6 proteins were predicted using the Prospect Software. RESULTS: The clinical manifestations, radiology, and MR imaging established the diagnosis of SEDT-PA. Pathologic examination demonstrated that the articular cartilage chondrocytes became hyper-proliferative and immature, while the density and diameter of matrix collagens were dramatically decreased. Mutation studies showed the two probands carried a deletion (840delT) mutation in maternal allele, that caused the truncated CCN6 protein to miss 43 residues in C-terminus; and a substitution mutation (1000T-->C, Ser334Pro) in paternal allele, which was also inherited down to other 4 members in the SEDT-PA kindred. The predicted 3D-conformational changes of the truncated mutant and the Ser334Pro mutant CCN6 proteins demonstrated that in comparison with the wild CCN6 protein, the single long peptide loop in the region from signal peptide to the beginning 24 amino acid residues in the first domain (IGFBP) was subjected to folding into two smaller cross-loops accompanied with a much shorter C-terminus in 840 delT truncated mutant CCN6 protein, and no substantial 3D-conformational change of Ser334Pro mutant CCN6 protein was detected except for the C-terminal peptide towards the opposite direction. CONCLUSION: Novel 840delT mutation of CCN6 gene is the leading cause of SEDT-PA though coexistence of T1000C substitution is necessary for the clinical onset of SEDT-PA, in which marked abnormalities of cartilage chondrocytes and matrix are morphologically and functionally presented.