To address the molecular mechanism underlying the functional defects of peripheral T cells in systemic lupus erythematosus (SLE), we focused on early signaling events. We demonstrated that protein expression of the TCR zeta chain was significantly decreased in peripheral T cells from patients with SLE compared to normal controls and patients with systemic sclerosis (SSc). Among those patients showing decreased TCR zeta chain expression, we found two patients with pronounced TCR zeta chain abnormalities, including an aberrant 14 kDa form in one and only trace expression in the other. RT-PCR, SSCP and subsequent cloning of the transcripts revealed that bases 468503, corresponding to exon 7, were deleted in both patients. Since exon 7 spans the GTP/GDP binding site and N-terminal tyrosine in the third ITAM domain of TCR zeta chain, the transcript lacking exon 7 may be responsible for altered signal transduction via TCR in these SLE patients.
ObjectiveDue to the continuing debates on the utility of high-dose methylprednisolone (MP) early after acute spinal cord injury (ASCI), we aimed to evaluate the therapeutic and adverse effects of high-dose MP according to the second National Acute Spinal Cord Injury Study (NASCIS-2) dosing protocol in comparison to no steroids in patients with ASCI by performing a meta-analysis on the basis of the current available clinical trials.MethodsWe searched PubMed and Cochrane Library (to May 22, 2018) for studies comparing neurologic recoveries, adverse events, and in-hospital costs between ASCI patients who underwent high-dose MP treatment or not. Data were synthesized with corresponding statistical models according to the degree of heterogeneity.ResultsWe enrolled 16 studies (1,863 participants) including 3 randomized controlled trials (RCTs) and 13 observational studies. Pooled results indicated that MP was not associated with an increase in motor score improvement (RCTs: p = 0.84; observational studies: p = 0.44) and incidence of recovery by at least one grade on the American Spinal Injury Association Impairment Scale or Frankel (p = 0.53). Meanwhile, MP did not lead to better sensory recovery (p = 0.07). However, MP was associated with a significantly higher incidence of gastrointestinal hemorrhage (p = 0.04) and respiratory tract infection (p = 0.01). The difference in the overall in-hospital costs between MP and control groups was not statistically significant (p = 0.78).ConclusionsBased on the current evidence, high-dose MP treatment, in comparison to controls, does not contribute to better neurologic recoveries but may increase the risk of adverse events in patients with ASCI. Therefore, we recommend against routine use of high-dose MP early after ASCI.
Tissue engineering has brought new possibilities for the treatment of spinal cord injury. Two important components for tissue engineering of the spinal cord include a suitable cell source and scaffold. In our study, we investigated induced mouse embryonic fibroblasts (MEFs) directly reprogrammed into neural stem cells (iNSCs), as a cell source. Three-dimensional (3D) electrospun poly (lactide-co-glycolide)/polyethylene glycol (PLGA-PEG) nanofiber scaffolds were used for iNSCs adhesion and growth. Cell growth, survival and proliferation on the scaffolds were investigated. Scanning electron microcopy (SEM) and nuclei staining were used to assess cell growth on the scaffolds. Scaffolds with iNSCs were then transplanted into transected rat spinal cords. Two or 8 weeks following transplantation, immunofluorescence was performed to determine iNSC survival and differentiation within the scaffolds. Functional recovery was assessed using the Basso, Beattie, Bresnahan (BBB) Scale. Results indicated that iNSCs showed similar morphological features with wild-type neural stem cells (wt-NSCs), and expressed a variety of neural stem cell marker genes. Furthermore, iNSCs were shown to survive, with the ability to self-renew and undergo neural differentiation into neurons and glial cells within the 3D scaffolds in vivo. The iNSC-seeded scaffolds restored the continuity of the spinal cord and reduced cavity formation. Additionally, iNSC-seeded scaffolds contributed to functional recovery of the spinal cord. Therefore, PLGA-PEG scaffolds seeded with iNSCs may serve as promising supporting transplants for repairing spinal cord injury (SCI).
BackgroundThe advent of human-induced pluripotent stem cells holds great promise for producing ample individualized hepatocytes. Although previous efforts have succeeded in generating hepatocytes from human pluripotent stem cells in vitro by viral-based expression of transcription factors and/or addition of growth factors during the differentiation process, the safety issue of viral transduction and high cost of cytokines would hinder the downstream applications. Recently, the use of small molecules has emerged as a powerful tool to induce cell fate transition for their superior stability, safety, cell permeability, and cost-effectiveness.MethodsIn the present study, we established a novel efficient hepatocyte differentiation strategy of human pluripotent stem cells with pure small-molecule cocktails. This method induced hepatocyte differentiation in a stepwise manner, including definitive endoderm differentiation, hepatic specification, and hepatocyte maturation within only 13 days.ResultsThe differentiated hepatic-like cells were morphologically similar to hepatocytes derived from growth factor-based methods and primary hepatocytes. These cells not only expressed specific hepatic markers at the transcriptional and protein levels, but also possessed main liver functions such as albumin production, glycogen storage, cytochrome P450 activity, and indocyanine green uptake and release.ConclusionsHighly efficient and expedited hepatic differentiation from human pluripotent stem cells could be achieved by our present novel, pure, small-molecule cocktails strategy, which provides a cost-effective platform for in vitro studies of the molecular mechanisms of human liver development and holds significant potential for future clinical applications.Electronic supplementary materialThe online version of this article (10.1186/s13287-018-0794-4) contains supplementary material, which is available to authorized users.
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SUMMARYWe have reported that tyrosine phosphorylation and expression of the T cell receptor zeta chain (TCR z ) was decreased in two systemic lupus erythematosus (SLE) patients with an abnormal TCR z lacking exon-7. To examine further the TCR z defect and any possible relationship with specific clinical features, we studied the expression of TCR z in peripheral blood T cells from 44 patients with SLE, 53 with other rheumatic diseases (30 rheumatoid arthritis (RA), 11 systemic sclerosis (SSc) and 12 primary Sjögren's syndrome(SjS)) and 39 healthy individuals. Flow cytometric analysis demonstrated a significant decrease in the expression of TCR z in SLE (P < 0·001), but not in the other rheumatic diseases. Immunoprecipitation experiments confirmed that the expression of TCR z in SLE T cells was decreased dramatically (normal: 111·4 ± 22·6%, SLE: 51·6 ± 37·4%, P < 0·0001). The decrease in TCR z did not correlate with disease activity, or with the dose of prednisolone (PSL). There were, however, three SLE patients in whom the level of TCR z expression normalized after treatment, suggesting that mechanisms responsible for the TCR z defect appear to be heterogeneous. These results confirm the defective expression and altered tyrosine phosphorylation of TCR z in a large proportion of SLE patients, suggesting that it may play an important role in T cell dysfunction in SLE.
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