Establishment of immortalized Schwann cells derived from rat embryo dorsal root ganglia

Establishment and characterization of immortalized human vocal fold fibroblast cell lines

PURPOSE

Vocal fold scarring is abnormal scar tissue in the lamina propria layer of the vocal fold. To facilitate investigation of vocal fold scarring, we established and characterized immortalized human vocal fold fibroblast (iHVFF) cell lines.

METHODS

Human vocal fold fibroblasts were immortalized by introducing Simian virus 40 large T antigen (SV40TAg) by transfection. Successfully transfected fibroblasts were sorted using flow cytometry. Immunofluorescence cytochemistry and western blot were applied to analyze the expression of fibronectin, vimentin, alpha-smooth muscle actin (α-SMA) and fibroblast activation protein (FAP). Cell proliferation rate was measured by CCK-8 assay. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to analyze the mRNA expression level.

RESULTS

The iHVFFs continued to proliferate for more than 30 generations and appeared spindle-shaped. The expression of Vimentin and α-SMA were detected in both iHVFFs and primary fibroblasts, and enhanced expression of FAP was observed in iHVFFs. Furthermore, iHVFFs exhibited an increased proliferative capability compared with the primary fibroblasts. RT-qPCR results suggested that collagen type III alpha 1 chain (COL3A1), interleukin-6, cyclooxygenase 2 (COX2), hyaluronan synthase 2 (HAS2), hepatocyte growth factor (HGF) in the iHVFFs significantly increased, whereas transforming growth factor-β1 (TGF-β1), elastin and matrix metallopeptidase-1 (MMP-1) expression significantly downregulated. No differences in mRNA expression of α-SMA, fibronectin and collagen type I alpha 2 chain (COL1A2) were noted between iHVFFs and primary fibroblasts.

CONCLUSION

iHVFFs can be used as a novel tool cell for future researches on the mechanisms of pathogenesis and treatment of vocal fold scarring.

CdTe quantum dots trigger oxidative stress and endoplasmic reticulum stress-induced apoptosis and autophagy in rat Schwann cell line RSC96

In the current study, the cytotoxicity and mechanisms of cadmium telluride quantum dots (CdTe QDs) on RSC96 cells were evaluated by exposing different doses of CdTe QDs for 24 h. Two types of cell death, including apoptosis and autophagy, as well as two important organelles, mitochondria and endoplasmic reticulum, were focused after CdTe QDs exposure. The results showed that CdTe QDs induced apoptosis in RSC96 cells in a concentration-dependent manner; promoted the accumulation of intracellular reactive oxygen species; decreased the mitochondrial membrane potential; caused the release of cytochrome c; and also increased the expression of Bcl-2 associated X protein, caspase-3, and cytochrome c proteins and decreased the expression of Bcl-2 protein. Further results also confirmed that CdTe QDs could be internalized by RSC96 cells, and the exposure and internalization of CdTe QDs could induce excessive endoplasmic reticulum stress in the cells, and the expression levels of binding immunoglobulin protein, C/EBP homologous protein, and caspase12 proteins were increased in a concentration-dependent manner. Moreover, autophagy-related proteins LC3II, Beclin1, and P62 all increased after CdTe QDs exposure, suggesting that CdTe QDs exposure both promoted autophagosome formation and inhibited autophagosome degradation, and that CdTe QDs affected the autophagic flow in RSC96 cells. In conclusion, CdTe QDs are able to cause apoptosis and autophagy in RSC96 cells through mitochondrial and endoplasmic reticulum stress pathways, and the possible neurotoxicity of CdTe QDs should be further investigated.

Schwann cell-derived exosomes: Janus-faced mediators of regeneration and disease

The phenotypic plasticity of Schwann cells (SCs) has contributed to the regenerative potential of the peripheral nervous system (PNS), but also pathological processes. This double-sided effect has led to an increasing attention to the role of extracellular vesicles (EVs) or exosomes in SCs to examine the intercellular communication between SCs and their surroundings. Here, we first describe the current knowledge of SC and EV biology, which forms the basis for the updates on advances in SC-derived exosomes research. We seek to explore in-depth the exosome-mediated molecular mechanisms involved in the regulation of SCs and their microenvironment. This review concludes with potential applications of SC-derived exosomes as delivery vehicles for therapeutics and biomarkers. The goal of this review is to emphasize the crucial role of SC-derived exosomes in the functional integration of the PNS, highlighting an emerging area in which there is much to explore and re-explore.

Cell populations in neonatal rat peripheral nerves identified by single-cell transcriptomics

Peripheral nerves connect central nerves with target tissues and organs and execute vital signal transduction functions. Although sub-types of neurons have been defined, the heterogeneity of cell populations in peripheral nerves, especially Schwann cells, has not been well demonstrated. Here, we collected sciatic nerves (SN) and dorsal root ganglia (DRG) from neonatal (1-day old) rats and classified cell populations by high-coverage single-cell sequencing. A total of 10 types of cells, including endothelial cells, erythrocytes, fibroblasts, monocytic cells, neurons, neutrophils, pericytes, satellite cells, Schwann cells, and vascular smooth muscle cells, were identified by transcriptome-based cell typing. The comparisons of cells in neonatal rat SN and DRG revealed distinct atlas in different tissue localizations. Investigations of ligand-receptor interactions showed that there existed direct cell-cell communications between endothelial cells and fibroblasts in SN and among endothelial cells, fibroblasts, and vascular smooth muscle cells in DRG. Schwann cells in neonatal rats were further sub-grouped to four sub-types, including LOC100134871 and Hbb expressing Schwann cell sub-type 1, Cldn19 and Emid1 expressing Schwann cell sub-type 2, Timp3 and Col5a3 expressing Schwann cell sub-type 3, and Cenpf and Mki67 expressing Schwann cell sub-type 4. These Schwann cell sub-types exhibited distinct genetic features and functional enrichments. Collectively, our results illustrated the diversity and cellular complexity of peripheral nerves at the neonatal stage and revealed the heterogeneity of Schwann cells in the peripheral nervous system.

Bioprinting: From Tissue and Organ Development to in Vitro Models

Bioprinting techniques have been flourishing in the field of biofabrication with pronounced and exponential developments in the past years. Novel biomaterial inks used for the formation of bioinks have been developed, allowing the manufacturing of in vitro models and implants tested preclinically with a certain degree of success. Furthermore, incredible advances in cell biology, namely, in pluripotent stem cells, have also contributed to the latest milestones where more relevant tissues or organ-like constructs with a certain degree of functionality can already be obtained. These incredible strides have been possible with a multitude of multidisciplinary teams around the world, working to make bioprinted tissues and organs more relevant and functional. Yet, there is still a long way to go until these biofabricated constructs will be able to reach the clinics. In this review, we summarize the main bioprinting activities linking them to tissue and organ development and physiology. Most bioprinting approaches focus on mimicking fully matured tissues. Future bioprinting strategies might pursue earlier developmental stages of tissues and organs. The continuous convergence of the experts in the fields of material sciences, cell biology, engineering, and many other disciplines will gradually allow us to overcome the barriers identified on the demanding path toward manufacturing and adoption of tissue and organ replacements.

Low-frequency pulsed electromagnetic field pretreated bone marrow-derived mesenchymal stem cells promote the regeneration of crush-injured rat mental nerve

Bone marrow-derived mesenchymal stem cells (BMSCs) have been shown to promote the regeneration of injured peripheral nerves. Pulsed electromagnetic field (PEMF) reportedly promotes the proliferation and neuronal differentiation of BMSCs. Low-frequency PEMF can induce the neuronal differentiation of BMSCs in the absence of nerve growth factors. This study was designed to investigate the effects of low-frequency PEMF pretreatment on the proliferation and function of BMSCs and the effects of low-frequency PEMF pre-treated BMSCs on the regeneration of injured peripheral nerve using in vitro and in vivo experiments. In in vitro experiments, quantitative DNA analysis was performed to determine the proliferation of BMSCs, and reverse transcription-polymerase chain reaction was performed to detect S100 (Schwann cell marker), glial fibrillary acidic protein (astrocyte marker), and brain-derived neurotrophic factor and nerve growth factor (neurotrophic factors) mRNA expression. In the in vivo experiments, rat models of crush-injured mental nerve established using clamp method were randomly injected with low-frequency PEMF pretreated BMSCs, unpretreated BMSCs or PBS at the injury site (1 × 10⁶ cells). DiI-labeled BMSCs injected at the injury site were counted under the fluorescence microscope to determine cell survival. One or two weeks after cell injection, functional recovery of the injured nerve was assessed using the sensory test with von Frey filaments. Two weeks after cell injection, axonal regeneration was evaluated using histomorphometric analysis and retrograde labeling of trigeminal ganglion neurons. In vitro experiment results revealed that low-frequency PEMF pretreated BMSCs proliferated faster and had greater mRNA expression of growth factors than unpretreated BMSCs. In vivo experiment results revealed that compared with injection of unpretreated BMSCs, injection of low-frequency PEMF pretreated BMSCs led to higher myelinated axon count and axon density and more DiI-labeled neurons in the trigeminal ganglia, contributing to rapider functional recovery of injured mental nerve. These findings suggest that low-frequency PEMF pretreatment is a promising approach to enhance the efficacy of cell therapy for peripheral nerve injury repair.