Cell-based transplantation strategies hold great potential for spinal cord injury (SCI) repair. Chitosan scaffolds have therapeutic benefits for spinal cord regeneration. Human dental pulp stem cells (DPSCs) are abundant available stem cells with low immunological incompatibility and can be considered for cell replacement therapy. The purpose of this study is to investigate the role of chitosan scaffolds in the neural differentiation of DPSCs in vitro and to assess the supportive effects of chitosan scaffolds in an animal model of SCI. DPSCs were incubated with chitosan scaffolds. Cell viability and the secretion of neurotrophic factors were analyzed. DPSCs incubated with chitosan scaffolds were treated with neural differentiation medium for 14 days and then neural genes and protein markers were analyzed by Western blot and reverse transcription plus the polymerase chain reaction. Our study revealed a higher cell viability and neural differentiation in the DPSC/chitosan-scaffold group. Compared with the control group, the levels of BDNF, GDNF, b-NGF, and NT-3 were significantly increased in the DPSC/chitosan-scaffold group. The Wnt/β-catenin signaling pathway played a key role in the neural differentiation of DPSCs combined with chitosan scaffolds. Transplantation of DPSCs together with chitosan scaffolds into an SCI rat model resulted in the marked recovery of hind limb locomotor functions. Thus, chitosan scaffolds were non-cytotoxic and provided a conducive and favorable microenvironment for the survival and neural differentiation of DPSCs. Transplantation of DPSCs might therefore be a suitable candidate for treating SCI and other neuronal degenerative diseases.

Objective To retrospectively analyze the chest computed tomography (CT) features in patients with coronavirus disease 2019 (COVID-19) pneumonia. Methods From January 9, 2020, to February 26, 2020, totally 56 laboratory-confirmed patients with COVID-19 underwent chest CT. For 40 patients, follow-up CT scans were obtained. The CT images were evaluated for the number, type and distribution of the opacity, and the affected lung lobes. Furthermore, the initial CT scan and the follow-up CT scans were compared. Results Forty patients (83.6%) had two or more opacities in the lung. Eighteen (32.7%) patients had only ground-glass opacities; twenty-nine patients (52.7%) had ground-glass and consolidative opacities; and eight patients (14.5%) had only consolidation. A total of 43 patients (78.2%) showed two or more lobes involved. The opacities tended to be both in peripheral and central (30/55, 54.5%) or purely peripheral distribution (25/55, 45.5%). Fifty patients (90.9%) had the lower lobe involved. The first follow-up CT scans showed that twelve patients (30%) had improvement, 26 (65%) patients had mild-moderate progression, and two patients (5%) had severe progression with "white lungs." The second follow-up CT showed that 22 patients (71%) showed improvement compared with the first follow-up CT, four patients (12.9%) had aggravated progression, and five patients (16.1%) showed unchanged radiographic appearance. Conclusions The common CT features of COVID-19 pneumonia are multiple lung opacities, multiple types of the opacity (ground-glass, ground-glass and consolidation, and consolidation alone), and multiple lobes especially the lower lobe involved. Follow-up CT could demonstrate the rapid progression of COVID-19 pneumonia (either in aggravation or absorption). Key Points • The predominant CT features of COVID-19 pneumonia are multiple ground-glass opacities with or without consolidation and, with both lungs, multiple lobes and especially the lower lobe affected. • CT plays a crucial role in early diagnosis and assessment of COVID-19 pneumonia progression. • CT findings of COVID-19 pneumonia may not be consistent with the clinical symptoms or the initial RT-PCR test results.

Dental pulp stem cells (DPSCs) were the most widely used seed cells in the field of neural regeneration and bone tissue engineering, due to their easily isolation, lack of ethical controversy, low immunogenicity and low rates of transplantation rejection. The purpose of this study was to investigate the role of basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) on neural differentiation of DPSCs in vitro. DPSCs were cultured in neural differentiation medium containing NGF and bFGF alone or combination for 7 days. Then neural genes and protein markers were analyzed using western blot and RT-PCR. Our study revealed that bFGF and NGF increased neural differentiation of DPSCs synergistically, compared with bFGF and NGF alone. The levels of Nestin, MAP-2, βIII-tubulin and GFAP were the most highest in the DPSCs + bFGF + NGF group. Our results suggested that bFGF and NGF signifiantly up-regulated the levels of Sirt1. After treatment with Sirt1 inhibitor, western blot, RT-PCR and immunofluorescence staining showed that neural genes and protein markers had markedly decreased. Additionally, the ERK and AKT signaling pathway played a key role in the neural differentiation of DPSCs stimulated with bFGF + NGF. These results suggested that manipulation of the ERK and AKT signaling pathway may be associated with the differentiation of bFGF and NGF treated DPSCs. Our date provided theoretical basis for DPSCs to treat neurological diseases and repair neuronal damage.

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Facet joint osteoarthritis is common lumbar osteoarthritis characterized by facet joint cartilage degeneration. However, the molecular basis of facet joint osteoarthritis remains largely undetermined. In the current study, we collected facet joint tissue samples from 10 control patients and 48 patients with facet joint osteoarthritis (20 patients with moderate degeneration and 28 with severe degeneration). The control patients underwent internal fixation of the lumbar spine due to vertebral fracture. RNA deep sequencing was performed, and Bioinformatic tools were applied. Among top 30 enriched signaling pathways, we focused on two inflammation-related signaling pathways, Wnt and NF-κB signaling pathways. Subsequently, using the quantitative RT-PCR analysis, we confirmed that in Wnt signaling pathway, the mRNA levels of Dickkopf WNT Signaling Pathway Inhibitor 2 (DKK2), Sex-determining Region Y-box 17 (SOX17), MYC, Cyclin D1, Calcium/Calmodulin Dependent Protein Kinase II Alpha (CAMK2A), and Wnt Family Member 11 and 5 were increased in facet joint osteoarthritis, while the mRNA levels of WNT Inhibitory Factor 1, Casein Kinase 1 Alpha 1, Transcription Factor 7/Lymphoid Enhancer Binding Factor 1 (TCF7/LEF1), and VANGL Planar Cell Polarity Protein 2 were decreased. In NF-κB signaling pathway, the mRNA levels of C-C Motif Chemokine Ligand 4 (CCL4) and C-C Motif Chemokine Ligand 4 Like 2 (CCL4L2) were increased, while the mRNA levels of BCL2 Related Protein A1 were decreased. These results suggest that Wnt and NF-κB signaling may be altered in the process of facet joint cartilage degeneration. The present study will expand our understanding of the molecular bases underlying facet joint osteoarthritis.

Department of Stomatology; Affiliated Hospital of Nantong University, Nantong; Nantong University; 226001, Nantong, Jiangsu, PR China y These authors equally contributed to this work, and should be considered as joint first authors.Keywords: astrocyte proliferation, b-catenin, p27, PKM2, spinal cord injuryAbbreviations: CNS, Central nervous system; CDKs, cyclin-dependent kinases; CAK, CDK activating kinase; E2F, E2 promoter-binding protein dimerization partners; GFAP, Glial fibrillary acidic protein; GAPDH, Glyceraldehyde-3-phosphate dehydrogenase; NeuN, Neuronal nuclei; PCNA, Proliferating cell nuclear antigen; PEP, phosphoenolpyruvate; PK, Pyruvate kinase; PKM2, pyruvate kinase M2; pRb, protein retinoblastoma; SCI, Spinal cord injury; EGFR, Epidermal growth factor receptor.Aberrant functionality of the cell cycle has been implicated in the pathology of traumatic SCI. Although it has been reported that the expressions of various cell cycle related proteins were altered significantly following SCI, detailed information on the subject remains largely unclear. The embryonic pyruvate kinase M2 (PKM2) is an important metabolic kinase in aerobic glycolysis or the warburg effect, however, its functions in central nervous system (CNS) injury remains elusive. Here we demonstrate that PKM2 was not only significantly upregulated by western blot and immunohistochemistry but certain traumatic stimuli also induced translocation of PKM2 into the nucleus in astrocytes following spinal cord injury (SCI). Furthermore, the expression levels and localization of p-b-catenin, p27, cyclin D1 and PCNA were correlated with PKM2 after SCI. In vitro, we also found that PKM2 co-immunoprecipitation with p-b-catenin and p27 respectively. Knockdown of PKM2 apparently decreased the level of PCNA, cyclinD1, p27 in primary astrocyte cells. Taken together, our findings indicate that nuclear translocation of PKM2 promotes astrocytes proliferation after SCI through modulating cell cycle signaling. These discoveries firstly uncovered the role of PKM2 in spinal cord injury and provided a potential therapeutic target for CNS injury and repair.