Fibroblast exosomal TFAP2C induced by chitosan oligosaccharides promotes peripheral axon regeneration via the miR-132-5p/CAMKK1 axis.

Chitosan and its degradation product, oligosaccharides, have been shown to facilitate peripheral nerve regeneration. However, the underlying mechanisms are not well understood. In this study, we analyzed the protein expression profiles in sciatic nerves after injury using proteomics. A group of proteins related to exosome packaging and transport is up-regulated by chitosan oligosaccharides (COS), implying that exosomes are involved in COS-induced peripheral nerve regeneration. In fact, exosomes derived from fibroblasts (f-EXOs) treated with COS significantly promoted axon extension and regeneration. Exosomal protein identification and functional studies, revealed that TFAP2C is a key factor in neurite outgrowth induced by COS-f-EXOs. Furthermore, we showed that TFAP2C targets the pri-miRNA-132 gene and represses miR-132-5p expression in dorsal root ganglion neurons. Camkk1 is a downstream substrate of miR-132-5p that positively affects axon extension. In rats, miR-132-5p antagomir stimulates CAMKK1 expression and improves axon regeneration and functional recovery in sciatic nerves after injury. Our data reveal the mechanism for COS in axon regeneration, that is COS induce fibroblasts to produce TFAP2C-enriched EXOs, which are then transferred into axons to promote axon regeneration via miR-132-5p/CAMKK1. Moreover, these results show a new facet of fibroblasts in axon regeneration in peripheral nerves.

Conductive biocomposite hydrogels with multiple biophysical cues regulate schwann cell behaviors.

Peripheral nerve injuries are serious clinical events, and surgical treatment has certain limitations. Conductive hydrogels are promising biomaterials for neural tissue engineering, as they can enhance the functionality of neurons and Schwann cells (SCs) by mimicking the biophysical and biochemical cues existing in the natural extracellular matrix. It remains unexplored, however, whether there is a connection between the effects of different cues, such as hydrogel elasticity and conductivity, on SC fate. In the present work, we fabricated a series of conductive biocomposite hydrogels with the combination of silk fibroin (SF) and graphene oxide (GO) nanosheets and demonstrated an approach to control hydrogel electrical conductivity, independent of matrix elasticity and polymer concentration. Our results indicated that the soft substrates play a more critical role in SC survival, proliferation, spreading, and gene expression of neurotrophic factors, while the increased conductivity may also be beneficial to SC functional behaviors. These findings may promote the understanding of cell-matrix interactions and provide new insights for the design of neural tissue engineering scaffolds.

Exosomal miR-673-5p from fibroblasts promotes Schwann cell-mediated peripheral neuron myelination by targeting the TSC2/mTORC1/SREBP2 axis.

Peripheral myelination is a complicated process, wherein Schwann cells (SCs) promote the formation of the myelin sheath around the axons of peripheral neurons. Fibroblasts are the second resident cells in the peripheral nerves; however, the precise function of fibroblasts in SC-mediated myelination has rarely been examined. Here, we show that exosomes derived from fibroblasts boost myelination-related gene expression in SCs. We used exosome sequencing, together with bioinformatic analysis, to demonstrate that exosomal microRNA miR-673-5p is capable of stimulating myelin gene expression in SCs. Subsequent functional studies revealed that miR-673-5p targets the regulator of mechanistic target of the rapamycin (mTOR) complex 1 (mTORC1) tuberous sclerosis complex 2 in SCs, leading to the activation of downstream signaling pathways including mTORC1 and sterol-regulatory element binding protein 2. In vivo experiments further confirmed that miR-673-5p activates the tuberous sclerosis complex 2/mTORC1/sterol-regulatory element binding protein 2 axis, thus promoting the synthesis of cholesterol and related lipids and subsequently accelerating myelin sheath maturation in peripheral nerves. Overall, our findings revealed exosome-mediated cross talk between fibroblasts and SCs that plays a pivotal role in peripheral myelination. We propose that exosomes derived from fibroblasts and miR-673-5p might be useful for promoting peripheral myelination in translational medicine.

[Effects of emulsified isoflurane preconditioning on LPS-induced acute lung injury in rats].

OBJECTIVE: To investigate the effects of emulsified isoflurane preconditioning on LPS-induced acute lung injury in rats. METHODS: Acute lung injury was induced by the administration of LPS 8 mg/kg intravenously in male Sprague-Dawley rats. The ratswere randomly assigned to 4 groups: LPS-induced acute lung injury group (LPS, n = 10); emulsified Isoflurane Preconditioning group (EISO, n = 10); Intralipid pre-treated group (INT, n = 10), and saline pre-reated control group (CON, n = 5). In the later 3 groups, 2 mL/kg NS, IL and EISO were infused intravenously for 30 min before the administration of LPS respectively. The animals were then observed for 5 hours. The mean arterial blood pressure(MAP) and heart rate(HR) were monitored hourly. Arterial blood gas (ABG) was measured for oxygenation index (OI) at the end of 5h. The blood samples were taken for the measurements of plasma tumor necrosis factor-alpha (TNF-alpha) and interleukin-6(IL-6). The lungs were removed for the measurements of wet/dry (W/D) weight ratio, as well as the levels of malondialdehyde (MDA), superoxide dismutase (SOD), myeloperoxidase (MPO). RESULTS: The OI of group CON was 435 +/- 30, group LPS 225 +/- 49, group EISO 367 +/- 41, and group INT 267 +/- 41. Compared with group CON, OI and pulmonary SOD activity significantly decreased while plasma TNF-alpha, IL-6 concentration and pulmonary MDA level, MPO activity increased in LPS, EISO and INT groups. The plasma TNF-alpha, IL-6 concentration, pulmonary MDA level and pulmonary MPO activity of group EISO were lower while OI and pulmonary SOD activity were higher than those of group LPS. CONCLUSION: The emulsified isoflurane pretreatment can ameliorate LPS-induced acute lung injury in rats.

[The expression of caspase-3, bFGF and MVD in laryngeal squamous cell carcinoma and the relationship among them].

OBJECTIVE: To investigate the expression of Caspase-3 and bFGF in laryngeal squamous cell carcinoma and the affection angiogenesis. METHOD: Immunohistochemistry was used to detect the expression of Caspase-3. bFGF and MVD in 36 cases of para-carcinoma tissue and 67 cases of laryngeal squamous cell carcinoma. RESULT: The expression of bFGF in laryngeal squamous cell carcinoma was significantly higher than that in para-carcinoma tissue (P < 0.05), however the expression of Caspase-3 was significantly higher in para-carcinoma tissue than that in Laryngeal squamous cell carcinoma (P < 0.05). In laryngeal carcinoma, the expression of bFGF and Caspase-3 were associated with differentiation, lymph node metastasis and clinical stage (P < 0.05), but was independent of clinical classification,smoking history, sex and gender (P > 0.05). A significantly negative correlation was found between hFGF and Caspase-3 (P < 0.05). The value of MVD in laryngeal squamous cell carcinoma was significantly higher than that in para-carcinoma tissue (P < 0.05), and was significantly associated with lymph node metastasis (P < 0.05), but not associated with age, gender, differentiation, clinical stage, clinical classification or smoking history. The MVD of the tissue with positive expression of bFGF was significantly higher than that with negative expression of bFGF in laryngeal squamous cell carcinoma (P < 0.05). There was no significant difference between the MVI) of the tissue with positive expression of bFGF and that with negative expression of bFGF in laryngeal squamous cell carcinoma (P > 0.05). CONCLUSION: bFGF was positively related to Caspase-3, which might play an important role in the carcinogenesis and development of laryngeal carcinoma by synergic effect.

[Expression of EMS1 protein and its clinical significance in laryngeal carcinoma].

OBJECTIVE: To investigate the expression of EMS1 in laryngeal carcinoma and its clinical significance. METHOD: The expression of EMS1 protein was measured in 40 samples of, 40 samples of para carcinoma tissues (which were near to cutting margin of laryngeal carcinoma tissue over 0.5 cm), and 20 samples of normal laryngeal mucosa as controls by Flow Cytometer (Epics-XL II). RESULT: The quantity and percentage of EMS1 protein expression in laryngeal carcinoma tissues was significantly higher than those in para carcinoma and in normal laryngeal mucosa tissues respectively (P<0.05). There was no significant expression difference between the para carcinoma tissues and normal laryngeal mucosa tissues. There were positive correlation between the expressions of EMS1 protein and metastasis, pathological grade and clinical stage in laryngeal carcinoma. But there were not relationship with patients' clinical classification, tumor size, smoking history, age and sex. CONCLUSION: The high expression of EMS1 may contribute to the carcinogenesis and development of laryngeal carcinoma. The expression of EMS1 protein is an important index of judging differentiation, infiltration, metastasis and staging of laryngeal carcinoma.

Isolation and characterization of cellulose obtained from ultrasonic irradiated sugarcane bagasse.

Cell walls of sugarcane bagasse were first delignified with chlorite followed by ultrasonic irradiation and then by two-step sequential extractions at 23 degrees C with 15 and 18% KOH for 2 h, 15 and 18% NaOH for 2 h, 8 and 10% KOH for 12 h, and 8 and 10% NaOH for 12 h and by a single one-stage isolation with 10% KOH for 16 h and with 10% NaOH for 16 h, which released 79.4, 81.8, 83.6, 85.7, 61.5, and 65.6% of the original hemicelluloses, and subsequently yielded 50.7, 49.5, 48.6, 47.8, 57.2, and 55.4% of the cellulose, respectively. The six cellulosic preparations were free of bound lignin and had a purity of 77.1-90.1% with the intrinsic viscosity (eta), viscosity average degree of polymerization, and molecular weight (M(w)) ranging from 534.1 to 631.6 mL g(-1), from 1858.1 to 2238.2 mL g(-1), and from 301000 to 362600 g mol(-1), respectively. The structural features of the isolated six cellulosic samples were comparatively examined by Fourier transform infrared and cross-polarization/magic angle spinning (13)C NMR spectroscopy and X-ray diffraction, and their thermal stability was investigated by using thermogravimetric analysis. It was found that all of the cellulosic preparations have the typical cellulose I structure but the crystallinity of the SCB cellulose was lower than that of flax, cotton, and kenaf.

[Transesophageal arterial oxygen saturation monitoring: an experimental study].

OBJECTIVE: To assess the sensitivity and accuracy of a novel transesophageal approach to monitoring the descending aortic oximetry (SeO2). METHODS: Nine dogs were involved in the experimental study. After the induction of anaesthesia, the carrier of the oximetry probe (Nellcor-D20, USA) was inserted into the lower segment of esophagus to monitor SeO2, and the probe was "locked" in position of post-descending aorta after the opening of thoracic cavity. Another probe was pasted on the surface of lingual mucous membrane. The readings and figures of SeO2 and surface of lingual mucosa oximetry (SmO2) were observed continuously and recorded simultaneously. Vital signs were monitored with pulse oxygen saturation (SpO2), invasive blood pressure by femoral artery, HR, EKG, PetCO2, T, FiO2. The SaO2 of blood gas analysis by femoral artery was used as the "gold standard" to calculated the relative and absolute deviations of SeO2 and SmO2. The changes of SeO2 and SaO2 were compared in case of acute hypoxia when values of SmO2 dropped to 90%, 80%, 70%, 60% and the patient was re-ventilated with 100% oxygen. RESULTS: (1) SeO2, SmO2 and SaO2 were 100% when the patients were ventilated with 100% oxygen. During hypoxia, the descent of SeO2 from 100% to 90% was (91.03+/-20.23) s (P<0.001) earlier than that of SmO2. And after re-supply of pure oxygen, the ascent of SeO2 was (25.9+/-6.0) s (P<0.05) earlier than that of SmO2. (2) SaO2 was well related with SeO2 and SmO2 (R2: 0.9884 and 0.9296) respectively. The relative and absolute deviations of SeO2 were 1.6% and 1.3%, while those of SmO2 were 7.6% and 6.1% from arterial blood samples SaO2. (3) There were no significant differences in MAP, HR, ECG, PetCO2 and T. CONCLUSION: This study showed that SeO2 monitoring is sensitive. It could accurately reflect the arterial oxygen saturation not only in normal condition but also during hypoxia and the re-ventilation with 100% oxygen. SeO2 responds faster and is closer to SaO2, compared with SmO2 measurements. This may be an alternative method in the cases where the monitoring of peripheral SpO2 is difficult.