皮肤瘙痒神经传导介质的研究进展

瘙痒是皮肤科的一种常见症状,是多因素相互作用的结果,其发生受到中枢和外周机制的双重调控,但具体发生机制尚不十分清楚。近年来随着研究的不断深入,多种物质如组胺、乙酰胆碱、5-羟色胺、蛋白酶和蛋白酶相关受体、细胞因子、阿片样肽等介质在瘙痒产生过程中起重要作用,这些介质通过刺激C类神经纤维或直接与皮肤感觉神经纤维受体相结合来介导瘙痒。本文就将皮肤瘙痒的神经传导及传导介质作一综述。     

Aloe-Emodin Protects RIN-5F (Pancreatic β-cell) Cell from Glucotoxicity via Regulation of Pro-Inflammatory Cytokine and Downregulation of Bax and Caspase 3

To determine the protective effect of aloe-emodin (AE) from high glucose induced toxicity in RIN-5F (pancreatic β-cell) cell and restoration of its function was analyzed. RIN-5F cells have been cultured in high glucose (25 mM glucose) condition, with and without AE treatment. RIN-5F cells cultured in high glucose decreased cell viability and increased ROS levels after 48 hr compared with standard medium (5.5 mM glucose). Glucotoxicity was confirmed by significantly increased ROS production, increased pro-inflammatory (IFN-γ, IL-1β,) & decreased anti-inflammatory (IL-6&IL-10) cytokine levels, increased DNA fragmentation. In addition, we found increased Bax, caspase 3, Fadd, and Fas and significantly reduced Bcl-2 expression after 48 hr. RIN-5F treated with both high glucose and AE (20 μM) decreased ROS generation and prevent RIN-5F cell from glucotoxicity. In addition, AE treated cells cultured in high glucose were transferred to standard medium, normal responsiveness to glucose was restored within 8hr and normal basal insulin release within 24 hr was achieved when compared to high glucose.     

Central nervous system and peripheral cell labeling by vascular endothelial cadherin-driven lineage tracing in adult mice

Understanding the contribution of endothelial cells to the progenitor pools of adult tissues has the potential to inform therapies for human disease.To address whether endothelial cells transdifferentiate into non-vascular cell types,we performed cell lineage tracing analysis using transgenic mice engineered to express a fluorescent marker following activation by tamoxifen in vascular endothelial cadherin promoter-expressing cells(VEcad-CreERT2;B6 Cg-Gt(ROSA)26Sortm9(CAG-tdTomato)Hze).Activation of target-cell labeling following 1.5 months of ad libitum feeding with tamoxifen-laden chow in 4–5 month-old mice resulted in the tracing of central nervous system and peripheral cells that include:cerebellar granule neurons,ependymal cells,skeletal myocytes,pancreatic beta cells,pancreatic acinar cells,tubular cells in the renal cortex,duodenal crypt cells,ileal crypt cells,and hair follicle stem cells.As Nestin expression has been reported in a subset of endothelial cells,Nes-CreERT2 mice were also utilized in these conditions.The tracing of cells in adult Nes-CreERT2 mice revealed the labeling of canonical progeny cell types such as hippocampal and olfactory granule neurons as well as ependymal cells.Interestingly,Nestin tracing also labeled skeletal myocytes,ileal crypt cells,and sparsely marked cerebellar granule neurons.Our findings provide support for endothelial cells as active contributors to adult tissue progenitor pools.This information could be of particular significance for the intravenous delivery of therapeutics to downstream endothelial-derived cellular targets.The animal experiments were approved by the Boise State University Institute Animal Care and Use Committee(approval No.006-AC15-018)on October 31,2018.     

HIFα Regulates Developmental Myelination Independent of Autocrine Wnt Signaling

The developing CNS is exposed to physiological hypoxia, under which hypoxia-inducible factor α (HIFα) is stabilized and plays a crucial role in regulating neural development. The cellular and molecular mechanisms of HIFα in developmental myelination remain incompletely understood. A previous concept proposes that HIFα regulates CNS developmental myelination by activating the autocrine Wnt/β-catenin signaling in oligodendrocyte progenitor cells (OPCs). Here, by analyzing a battery of genetic mice of both sexes, we presented in vivo evidence supporting an alternative understanding of oligodendroglial HIFα-regulated developmental myelination. At the cellular level, we found that HIFα was required for developmental myelination by transiently controlling upstream OPC differentiation but not downstream oligodendrocyte maturation and that HIFα dysregulation in OPCs but not oligodendrocytes disturbed normal developmental myelination. We demonstrated that HIFα played a minor, if any, role in regulating canonical Wnt signaling in the oligodendroglial lineage or in the CNS. At the molecular level, blocking autocrine Wnt signaling did not affect HIFα-regulated OPC differentiation and myelination. We further identified HIFα–Sox9 regulatory axis as an underlying molecular mechanism in HIFα-regulated OPC differentiation. Our findings support a concept shift in our mechanistic understanding of HIFα-regulated CNS myelination from the previous Wnt-dependent view to a Wnt-independent one and unveil a previously unappreciated HIFα–Sox9 pathway in regulating OPC differentiation.SIGNIFICANCE STATEMENT Promoting disturbed developmental myelination is a promising option in treating diffuse white matter injury, previously called periventricular leukomalacia, a major form of brain injury affecting premature infants. In the developing CNS, hypoxia-inducible factor α (HIFα) is a key regulator that adapts neural cells to physiological and pathologic hypoxic cues. The role and mechanism of HIFα in oligodendroglial myelination, which is severely disturbed in preterm infants affected with diffuse white matter injury, is incompletely understood. Our findings presented here represent a concept shift in our mechanistic understanding of HIFα-regulated developmental myelination and suggest the potential of intervening with an oligodendroglial HIFα-mediated signaling pathway to mitigate disturbed myelination in premature white matter injury.     

The impact of frost-damage on the quality and quantity of the secreted antigen-specific IgG repertoire

Freezing of alum-based vaccines drastically alters their colloidal composition and leads to irreversible cluster formation. The loss of stability is well described, but the impact of frost damage on the functionality of the induced and secreted antibody repertoire has not been studied in detail. We therefore applied our single-cell measurement platform to extract the frequencies of Immunoglobulin G-secreting cells in combination with individual secretion rates and affinities. We showed that, frost-damaged or not, the tested vaccine was able to generate similar frequencies of total and antigen-affine IgG-secreting cells. Additionally, the frost-damaged vaccine stimulated a similar T-cell cytokine secretion pattern when compared to the regularly stored vaccine. However, frost-damaged vaccines induced no efficient affinity maturation and a complete collapse of the affinity distribution was observed. This study unveiled the impact of frost-damage to alum-based vaccines on the induced secreted antibody repertoire, and illustrated the power of functional single-antibody analysis.     

Suppression of PRDX4 inhibits cell proliferation and invasion of ectopic endometrial stromal cells in endometriosis

Abstract

Oxidative stress (OS) has been proposed to play a role in the development of EMs. Peroxiredoxins are a family of antioxidant proteins that exhibit peroxidase activity in a thioredoxin-dependent manner, protecting cells against OS. The Western blotting results showed that the relative expression of PRDX4 was significantly increased in ectopic endometria compared with the normal endometria of EMs-free (p?<?.05). The H₂O₂ concentration was also significantly higher in the ectopic endometrium. PRDX4 siRNA was transfected into primary ectopic endometrial stromal cells (EESCs). The viability of the transfected EESCs was measured by CCK-8 assay, and the results showed significantly decreased cell viability. Furthermore, the apoptosis rate and ROS generation in flow cytometry assays were significantly increased after the knockdown of PRDX4 expression (p?<?.05). Scratch assays and transwell assays revealed that decreased expression of PRDX4 mediated by siRNA inhibited EESC migration and invasion. In conclusion, these findings indicate the potential role of PRDX4 in the development of EMs and PRDX4 as a possible therapeutic target for EMs treatment.     

Cost-effective differentiation of hepatocyte-like cells from human pluripotent stem cells using small molecules

Significant efforts have been invested into the differentiation of stem cells into functional hepatocyte-like cells that can be used for cell therapy, disease modeling and drug screening. Most of these efforts have been concentrated on the use of growth factors to recapitulate developmental signals under in vitro conditions. Using small molecules instead of growth factors would provide an attractive alternative since small molecules are cell-permeable and cheaper than growth factors. We have developed a protocol for the differentiation of human embryonic stem cells into hepatocyte-like cells using a predominantly small molecule–based approach (SM-Hep). This 3 step differentiation strategy involves the use of optimized concentrations of LY294002 and bromo-indirubin-3’-oxime (BIO) for the generation of definitive endoderm; sodium butyrate and dimethyl sulfoxide (DMSO) for the generation of hepatoblasts and SB431542 for differentiation into hepatocyte-like cells. Activin A is the only growth factor required in this protocol. Our results showed that SM-Hep were morphologically and functionally similar or better compared to the hepatocytes derived from the growth-factor induced differentiation (GF-Hep) in terms of expression of hepatic markers, urea and albumin production and cytochrome P450 (CYP1A2 and CYP3A4) activities. Cell viability assays following treatment with paradigm hepatotoxicants Acetaminophen, Chlorpromazine, Diclofenac, Digoxin, Quinidine and Troglitazone showed that their sensitivity to these drugs was similar to human primary hepatocytes (PHHs). Using SM-Hep would result in 67% and 81% cost reduction compared to GF-Hep and PHHs respectively. Therefore, SM-Hep can serve as a robust and cost effective replacement for PHHs for drug screening and development.