Roles of cerebrospinal fluid-contacting neurons as potential neural stem cells in the repair and regeneration of spinal cord injuries.

Cerebrospinal fluid-contacting neurons (CSF-cNs) represent a distinct group of interneurons characterized by their prominent apical globular protrusions penetrating the spinal cord's central canal and their basal axons extending towards adjacent cells. Identified nearly a century back, the specific roles and attributes of CSF-cNs have just started to emerge due to the historical lack of definitive markers. Recent findings have confirmed that CSF-cNs expressing PKD2L1 possess attributes of neural stem cells, suggesting a critical function in the regeneration processes following spinal cord injuries. This review aims to elucidate the molecular markers of CSF-cNs as potential neural stem cells during spinal cord development and assess their roles post-spinal cord injury, with an emphasis on their potential therapeutic implications for spinal cord repair.

Genetically predicted hypotaurine levels mediate the relationship between immune cells and intracerebral hemorrhage.

The evidence supports a strong link between immune cells and intracerebral hemorrhage (ICH). Nonetheless, the specific cause-and-effect associations between immune cells and ICH remain indeterminate. Here, our primary investigation compared immune cell infiltration in the ICH and sham groups using the GSE24265 dataset. Afterward, we extensively examined the relationship between immune cells and ICH by applying a two-sample Mendelian randomization (MR) analysis to identify the particular immune cells that may be associated with the initiation and advancement of ICH. Nevertheless, the specific processes that regulate the cause-and-effect connection between immune cells and ICH remain unknown. In this study, our objective was to investigate the connections between immune cell characteristics and plasma metabolites, as well as the links between plasma components and ICH. Our investigation uncovered that the levels of hypotaurine play a key role in the advancement of ICH, influencing the ratio of switched memory B cells among lymphocytes. Thus, our findings provide novel insights into the potential biological mechanisms underlying immune cell-mediated ICH.

Culture of cerebrospinal fluid-contacting neurons from neonatal mouse spinal cord.

Cerebrospinal fluid-contacting neurons (CSF-cNs) act crucial role in chemosensory and mechanosensory function in spinal cord. Recently, CSF-cNs were found to be an immature neuron and may be involved in spinal cord injury recovery. But how to culture it and explore its function in vitro are not reported in previous research. Here, we first reported culture and identification of CSF-cNs in vitro. We first established a protocol for in vitro culture of CSF-cNs from the cervical spinal cord of mice within 24 h after birth. Polycystic kidney disease 2-like 1 (PKD2L1)+ cells were isolated by fluorescence-activated cell sorting and expressed the neuron marker ß-tubulin III and CSF-cNs marker GABA. Intriguingly, PKD2L1+ cells formed neurosphere and expressed neural stem cell markers Nestin, Sox2 and GFAP. Thus, our research provided culture and isolation of CSF-cNs and this facilitate the investigation the CSF-cNs function in vitro.

Association between pressure ulcers and the risk of postoperative infections in male adults with spinal cord injury.

OBJECTIVE: Data about postoperative infections in male adults with spinal cord injury are scarce. We aimed to evaluate the association between prior exposure to pressure ulcers (PU) and the risk of postoperative infections in male adults with spinal cord injury (SCI). METHODS: We conducted a prospective study of male adults receiving surgery of SCI from January 2007 to December 2019. Postoperative infection included septicemia, pneumonia, surgical incision infection and urinary tract infection. A logistic regression analysis was applied. Risk ratios (RRs) and their corresponding 95% confidence intervals (CIs) were calculated. RESULTS: There were 408 patients with SCI in this study, which comprised 204 patients with prior PU and 204 patients without. The rate of postoperative infections within 14 days in patients with PU was 23.5%, which was higher than that of patients without PU (6.9%). The amounts to a 4.18-folds elevated risk of any postoperative infections with 14 days in patients with PU (RR: 4.18, 95% CI: 2.30-7.60, p-value: <0.001). With respect to specific infections, positive associations in pneumonia (RR: 4.18, 95% CI: 2.30-7.60, p-value: <0.001), surgical incision infection (RR: 4.18, 95% CI: 2.30-7.60, p-value: <0.001), and urinary tract infection (RR: 4.18, 95% CI: 2.30-7.60, p-value: <0.001) were also statistically significant. These results did not materially alter adjustment for potential risk factors. CONCLUSIONS: The study suggests an elevated risk of postoperative infections after surgery for SCI in male patients with prior exposure to pressure ulcers.

The neural stem cell properties of Pkd2l1+ cerebrospinal fluid-contacting neurons in vivo.

The neural stem cells (NSCs) in the ventricular-subventricular zone of the adult mammalian spinal cord may be of great benefit for repairing spinal cord injuries. However, the sources of NSCs remain unclear. Previously, we have confirmed that cerebrospinal fluid-contacting neurons (CSF-cNs) have NSC potential in vitro. In this study, we verified the NSC properties of CSF-cNs in vivo. In mouse spinal cords, Pkd2l1+ CSF-cNs localized around the central canal express NSC markers. In vitro, Pkd2l1+ CSF-cNs form a neurosphere and express NSC markers. Activation and proliferation of CSF-cNs can be induced by injection of the neurotrophic factors basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) into the lateral ventricle. Spinal cord injury (SCI) also induces NSC activation and proliferation of CSF-cNs. Collectively, our results demonstrate that Pkd2l1+ CSF-cNs have NSC properties in vivo and may be involved in SCI recovery.

The Neural Stem Cell Properties of PKD2L1+ Cerebrospinal Fluid-Contacting Neurons in vitro.

Cerebrospinal fluid-touching neurons (CSF-cNs) exist in the region surrounding the central canal of the spinal cord, which locate in the adult neurogenic niche. Previous research showed that CSF-cNs expressed the molecular markers of immature neural cells in vivo. Here, we explored the potential of CSF-cNs as neural stem cell in intro. We first found that PKD2L1+ CSF-cNs, isolating by FACS using the molecular marker PKD2L1 of CSF-cNs, expressed neural stem cells markers like Nestin, Sox2, and GFAP by immunofluorescence staining. PKD2L1+ CSF-cNs were able to form neurospheres and passaged in vitro. Immunofluorescence staining showed that the neurospheres forming by PKD2L1+ CSF-cNs also expressed neural stem cell markers Nestin, Sox2 and GFAP. The neurospheres expressed proliferation markers Ki67 and PCNA by immunofluorescence staining, indicating that the neurospheres forming by PKD2L1+ CSF-cNs were proliferative. The neurospheres, forming by CSF-cNs, had the ability of differentiation into neurons, astrocytes, and oligodendrocytes. Collectively, our data suggested that PKD2L1+ CSF-cNs have the properties of neural stem cells in vitro and may provide a promising approach for the repair of spinal cord injury.

Wnt7a promotes the osteogenic differentiation of human mesenchymal stem cells.

Mesenchymal stem cells (MSCs) have the ability of differentiating into osteoblasts. Elucidating the molecular mechanisms of MSC differentiation into osteoblasts may provide novel therapeutic strategies for bone­related diseases. Increasing evidence has confirmed that Wnt signaling plays the key role in osteoblast differentiation; however, the role of individual Wnt proteins in osteogenesis needs to be investigated. The present study thus aimed to explore the role of Wnt7a in bone formation. For this purpose, human bone­derived MSCs were identified by flow cytometry and the cell differentiation potential, including osteogenic and adipogenic differentiation was examined. In order to explore the role of Wnt7a in MSC osteogenic differentiation, Wnt7a expression was measured at the mRNA and protein level following treatment with the osteogenic inducer, bone morphogenetic protein (BMP)4/7, and following the induction of osteogenic or adipogenic differentiation. The ectopic expression of Wnt7a in MSCs was confirmed and its influence on MSC osteogenic differentiation was detected using osteocyte markers and by Alizarin Red S staining. Mechanistically, the influence of Wnt7a on Runt­related transcription factor 2 (RUNX2) expression was examined at the mRNA and protein level. The regulatory effects of Wnt7a on RUNX2 promoter activities were examined by promoter reporter assay, and by examining the binding of TCF1, a downstream target of Wnt, to the RUNX2 promoter by ChIP assay. The results revealed that the knockdown of Wnt7a in MSCs decreased the expression of osteocyte markers and inhibited osteogenic differentiation. In accordance, the overexpression of Wnt7a in MSCs increased the expression of osteocyte markers and promoted osteogenic differentiation. Mechanistically, the knockdown of Wnt7a in MSCs reduced RUNX2 expression and the overexpression of Wnt7a in MSCs promoted RUNX2 expression. Furthermore, it was confirmed that Wnt7a regulated RUNX2 promoter activities by promoter report assay, and by examining the binding of TCF1 to the RUNX2 promoter by ChIP assay. On the whole, the present study demonstrates that Wnt7a plays a key role in MSC differentiation into osteoblasts and the findings presented herein may provide a promising therapy target for bone­related diseases.

Cerebrospinal fluid-contacting neurons affect the expression of endogenous neural progenitor cells and the recovery of neural function after spinal cord injury.

OBJECTIVE: To explore the relationship between cerebrospinal fluid-contacting neurons (CSF-cNs) and endogenous neural progenitor cells (ENPCs) and whether CSF-cNs are involved in nerve repair after spinal cord injury (SCI). METHODS: Cholera toxin B-horseradish peroxidase complex (CB-HRP) and cholera toxin B conjugated with saporin (CB-SAP) were injected into the lateral ventricles of spinal cord injured rats to mark and destroy the CSF-cNs. Then the rats in the experimental group were injured by SCI. Observe the content and co-expression of CSF-cNs and ENPCs in rats of each group, and observe the recovery of motor function after SCI in each group. RESULTS: After the destruction of CSF-cNs, the number of ENPCs decreased significantly in the long term after the surgery, and the recovery of motor function also deteriorated as compared to the group with intact CSF-cNs. Meanwhile some cells in the spinal cord express both the biological marker of CSF-cNs and ENPCs. CONCLUSION: This study shows that the population of ENPCs and motor function recovery in SCI rats declined after the destruction of CSF-cNs, suggesting that CSF-cNs affect the ENPCs population and may be involved in the recovery of neural function after SCI.

Elevated Risk of Infections after Spinal Cord Surgery in Relation to Preoperative Pressure Ulcers: a Follow-up Study.

Factors associated with infections after spinal cord surgery were not fully understood. This study aimed to evaluate whether preoperative pressure ulcers was a risk factor of infections after spinal cord operation. A 1:1 matched follow-up study was performed in a tertiary referral center in southwest China between 2010 and 2015. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression analysis. A total of 334 patients with spinal cord surgery were recruited (167 patients with preoperative pressure ulcers and 167 patients without preoperative pressure ulcers). Participants previously exposed to pressure ulcers had an elevated risk of infections post spinal cord operation including surgical site infection (RR: 2.3, 95% CI: 1.1, 4.7), pneumonia (RR: 2.4, 95% CI: 1.1,5.3), urinary tract infection (RR: 2.8, 95% CI: 1.1, 7.3), any kinds of postoperative infections (RR: 3.4, 95% CI: 2.1, 5.6) and 30-day postoperative hospitalization for infections (RR: 2.6, 95% CI: 1.1, 6.0). The associations between preoperative pressure ulcers in stage III to IV and postoperative infections were also pronounced, but towards null in stage I to II. The study showed an increased risk of infections after spinal cord surgery in patients with preoperative pressure ulcers, indicative of an urgent need for monitoring postoperative infections and medical treatment for patients with pressure sores.

3-Iodothyronamine Acting through an Anti-Apoptotic Mechanism Is Neuroprotective Against Spinal Cord Injury in Rats.

This study aims to show how 3-iodothyronamine (T1AM) protects against spinal cord injury (SCI) in rats. We randomly divided adult female Sprague-Dawley rats (N=54) into three equal groups: (1) untreated control (n=18) (2) T1AM (n=18) (3) T1AM+EPPTB (n=18). The clamp method was used to produce SCI at the T10 segment, and the following data were collected 3, 5, and 7 days after the injury plus treatment. The mean BBB scores of both the control and T1AM+EPPTB groups were 1.5±0.5, 3.5±0.5, and 4.5±0.5 on days 3, 5, and 7 after SCI, respectively, whereas those for the T1AM group were 3.3±0.5, 5.3±0.5, and 7.5±0.5, a significant difference from the first two groups mentioned on each day (all P values <0.05). Although HE staining indicated that all three groups displayed neuronal degeneration and necrosis, disorganized spinal cord tissue structure, proliferation of glial cells, and spinal cord porosis, the damage was less in the T1AM group than in the other two groups. The number of apoptotic cells gradually increased in all three groups. However, while the mean numbers of apoptotic cells in the control (9.8%±2.6%, 14.2%±5.9%, 57.2%±15.1%) and T1AM+EPPTB groups (9.1%±3.0%, 13.4%±6.3%, 57.4%±11.1%) on days 3, 5, and 7, respectively, were not significantly different from each other, those in the T1AM group (2.3%±1.4%, 7.6%±1.8%, 36.1%±9.9%) were significantly lower than those in both the other groups at each time point (all P values <0.05). Thus, T1AM is involved in the apoptosis pathway through stimulation of TAAR1. The T1AM-TAAR1 interaction decreased spinal cord neuron apoptosis, reduced secondary SCI, and promoted hind limb motor function recovery in rats with SCI.

MicroRNA-34a alleviates steroid-induced avascular necrosis of femoral head by targeting Tgif2 through OPG/RANK/RANKL signaling pathway.

The study aims to investigate the effect of microRNA-34a (miR-34a) targeting Tgif2 on steroid-induced avascular necrosis of femoral head (SANFH) by regulating OPG/RANK/RANKL signaling pathway. SD rats were divided into normal control and model (RNAKL rat models) groups. The model group was further assigned into model control, negative control, miR-34a mimics and miR-34a inhibitors groups. QRT-PCR was applied to detect miR-34a, Tgif2, OPG, RANK and RNAKL mRNA expressions. Femoral head tissues were collected for Micro-CT scanning and HE staining. QRT-PCR and Western blotting were used to detect expressions of miR-34a, Tgif2, OPG, RANK, RANKL and Runx2, OPN and OC in bone tissues. Dual-luciferase reporter gene assay was used to testify the target relationship between miR-34a and Tgif2. Compared with the normal control group, the model group showed increased Tgif2, RANK and RANKL mRNA expressions, but decreased miR-34a and OPG mRNA expressions. Tgif2 mRNA expression was negatively correlated with miR-34a and OPG mRNA expressions. Micro-CT showed cystic degeneration of femoral head, with decreased bone volume/total volume (BV/TV), bone surface area/bone volume and trabecular number in the model control group compared with the normal control group. Compared with the model control group, the miR-34a mimics group showed increased BV/TV and trabecular thickness and Runx2, OPN and OC expressions, while the parameters decreased in the miR-34a inhibitors group. Compared with the normal control group, the other groups showed increased Tgif2, RANK and RANKL expressions but decreased miR-34a and OPG expressions. Compared with the model control group, Tgif2, RANK and RANKL expressions decreased and miR-34a and OPG expressions increased in the miR-34a mimics group, while the miR-34a inhibitors group had a reverse trend in contrast to the miR-34a mimics group. Tgif2 is a target gene of miR-34a. In conclusion, miR-34a can alleviate SANFH through targeting Tgif2 and further regulating OPG/RANK/RANKL signaling pathway. Impact statement miR-34a can alleviate SANFH through targeting Tgif2 and further regulating OPG/RANK/RANKL signaling pathway, which can be used as a new theoretical basis for SANFH treatment.

A comparison between nucleus pulposus-derived stem cell transplantation and nucleus pulposus cell transplantation for the treatment of intervertebral disc degeneration in a rabbit model.

INTRODUCTION: In recent years, nucleus pulposus cell (NPC) transplantation has been used to treat intervertebral disc degeneration (IDD); however, the degenerative nature of NPCs influences its effectiveness. Nucleus pulposus-derived stem cells (NPSCs), which are self-renewing, have high expansion potential and can adapt to the intervertebral disc (IVD) microenvironment and may have a better regenerative capacity, which is favourable for treating IDD. The aim of this study was to compare the effectiveness of transplantation with NPSCs and NPCs on the regeneration of the IVD in rabbit models. METHODS: NPSCs and NPCs were isolated from human degenerate nucleus pulposus tissue by differential adhesion method, and stem cell surface markers were detected by flow cytometry. Degenerative discs in rabbits were randomly distributed into three groups: NPSCs, NPCs and vehicle control group; the normal discs served as the normal control group. Cells of the P3 generation were prepared for transplantation. About 20 µl of cell suspension (NPSCs or NPCs) or DMEM was injected into corresponding discs, while the normal discs were left untreated. After 8 weeks, disc height was evaluated using X-ray, water content was evaluated by MRI, and gene and protein expression levels of collagen II and aggrecan in the nucleus were determined by real-time PCR and ELISA. RESULTS: NPCs and NPSCs from the P3 generation were polygonal and spindle-shaped, respectively. Both NPSCs and NPCs strongly expressed surface markers CD73, CD90, and CD105 and weakly expressed CD34 and CD45. The relative rates of expression of CD73, CD90, and CD105 were higher in NPSCs than in NPCs. After 8 weeks, X-ray results showed no significant difference in disc height index among the groups (p > 0.05). MRI revealed that the intensity of the nucleus pulposus signal was increased in NPSCs (p < 0.05). The results from PCR and ELISA demonstrated that NPSCs promoted gene and protein expression of aggrecan instead of collagen II (p < 0.05). CONCLUSION: Compared to NPCs, NPSCs harvested by differential adhesion method displayed a higher positive rate of stem cell surface markers and showed superior regenerative effectiveness for treating IDD in rabbit models. Therefore, NPSCs are potential candidates for cell therapy for the regeneration of the IVD.