Jinqian Liang

MicroRNA-10b promotes nucleus pulposus cell proliferation through RhoC-Akt pathway by targeting HOXD10 in intervetebral disc degeneration.

Aberrant proliferation of nucleus pulposus cell is implicated in the pathogenesis of intervertebral disc degeneration. Recent findings revealed that microRNAs, a class of small noncoding RNAs, could regulate cell proliferation in many pathological conditions. Here, we showed that miR-10b was dramatically upregulated in degenerative nucleus pulposus tissues when compared with nucleus pulposus tissues isolated from patients with idiopathic scoliosis. Moreover, miR-10b levels were associated with disc degeneration grade and downregulation of HOXD10. In cultured nucleus pulposus cells, miR-10b overexpression stimulated cell proliferation with concomitant translational inhibition of HOXD10 whereas restored expression of HOXD10 reversed the mitogenic effect of miR-10b. MiR-10b-mediated downregulation of HOXD10 led to increased RhoC expression and Akt phosphorylation. Either knockdown of RhoC or inhibition of Akt abolished the effect of miR-10b on nucleus pulposus cell proliferation. Taken together, aberrant miR-10b upregulation in intervertebral disc degeneration could contribute to abnormal nucleus pulposus cell proliferation through derepressing the RhoC-Akt pathway by targeting HOXD10. Our study also underscores the potential of miR-10b and the RhoC-Akt pathway as novel therapeutic targets in intervertebral disc degeneration.

Leptin Induces Cyclin D1 Expression and Proliferation of Human Nucleus Pulposus Cells via JAK/STAT, PI3K/Akt and MEK/ERK Pathways

Increasing evidence suggests that obesity and aberrant proliferation of nucleus pulposus (NP) cells are associated with intervertebral disc degeneration. Leptin, a hormone with increased circulating level in obesity, has been shown to stimulate cell proliferation in a tissue-dependent manner. Nevertheless, the effect of leptin on the proliferation of human NP cells has not yet been demonstrated. Here, we show that leptin induced the proliferation of primary cultured human NP cells, which expressed the leptin receptors OBRa and OBRb. Induction of NP cell proliferation was confirmed by CCK8 assay and immunocytochemistry and Real-time PCR for PCNA and Ki-67. Mechanistically, leptin induced the phosphorylation of STAT3, Akt and ERK1/2 accompanied by the upregulation of cyclin D1. Pharmacological inhibition of JAK/STAT3, PI3K/Akt or MEK/ERK signaling by AG490, Wortmannin or U0126, respectively, reduced leptin-induced cyclin D1 expression and NP cell proliferation. These experiments also revealed an intricate crosstalk among these signaling pathways in mediating the action of leptin. Taken together, we show that leptin induces human NP cell cyclin D1 expression and proliferation via activation of JAK/STAT3, PI3K/Akt or MEK/ERK signaling. Our findings may provide a novel molecular mechanism that explains the association between obesity and intervertebral disc degeneration.

Leptin-mediated cytoskeletal remodeling in chondrocytes occurs via the RhoA/ROCK pathway†

Leptin affects a number of cell signaling pathways, at present, the mechanism(s) by which leptin affects the cartilage cells in OA patient is not well understood. The current study seeks to elucidate whether leptin induces cytoskeletal remodeling in chondrocytes and the possible involvement of the RhoA/ROCK pathway and its downstream mediators in this process. Fluorescent resonance energy transfer (FRET) and western analysis were used to determine the activations of the key proteins in the RhoA/LIMK1/Cofilin pathway. Accompanying cytoskeletal remodeling was elucidated. Upon leptin stimulation, a substantial increase of RhoA activity localized at one end of the cell was observed from 2 to 30 min post‐stimulation. The results of Western blot showed leptin significantly increased LIMK1 and cofilin‐2 phosphorylation in a time‐dependent manner with maximal stimulation attained 60 min and 24 h post‐stimulation, respectively. Chondrocytes stimulated with leptin exhibited an epithelioid morphology with increased cellular spreading. F‐actin in leptin‐stimulated chondrocytes also showed more intense cytoplasmic staining with occasional localization along filamentous structures. The results indicate that leptin activates the RhoA/ROCK/LIMK/cofilin pathway, which results in cytoskeletal reorganization in chondrocytes. These findings provide novel evidence supporting the possible involvement of leptin and the RhoA pathway in the pathogenesis of OA.

Risk factors for delayed infections after spinal fusion and instrumentation in patients with scoliosis. Clinical article.

OBJECT There are limited published data about the risk factors for the development of delayed infections after spinal fusion and instrumentation in the population with scoliosis. The objective of this study was to evaluate the predictive factors of development of delayed infections in patients with scoliosis who underwent surgical treatment. METHODS A total of 17 patients with scoliosis and delayed infections were identified from 3463 patients with scoliosis who received surgical treatment. The control group was composed of 85 patients with scoliosis without infections, matched for sex, age, approximate date of surgery, and diagnosis. These 2 groups were compared for demographic distribution and clinical data to investigate the predictive factors of delayed infections. RESULTS The overall incidence rate of delayed infections was 0.49%. The variables of age, body mass index, and number of levels fused were similar between the 2 groups. The average primary curve magnitude for the delayed infection and control (uninfected) groups was 80.4° ± 27.0° (range 47°-135°) and 66.3° ± 11.6° (range 42°-95°), respectively (p = 0.001). Operation time in the group with delayed infections was 384.7 ± 115.9 minutes versus 254.4 ± 79.2 minutes in the control group (p = 0.000), and estimated blood loss was 1342.2 ± 707.2 ml versus 833.9 ± 235.6 ml (p = 0.000) in these 2 groups, respectively. The perioperative mean red blood cell transfusion requirement in the delayed infection group was significantly higher than that found in patients without infections (2.8 ± 2.3 units/patient versus 1.1 ± 1.6 units/patient, respectively; p = 0.000). Logistic regression analysis showed that operation time and allogenic blood transfusion were the 2 independent predictors of delayed infections (odds ratio [OR] 1.021, 95% confidence interval [CI] 1.010-1.033, and OR 1.546, 95% CI 1.048-2.278, respectively). CONCLUSIONS The occurrence of a delayed infection in patients with scoliosis who undergo surgical treatment is most likely multifactorial and is related to surgical time and the use of allogenic blood transfusion.

Leptin downregulates aggrecan through the p38-ADAMST pathway in human nucleus pulposus cells.

The mechanistic basis of obesity-associated intervertebral disc degeneration (IDD) is unclear. Aberrant expression of aggrecan and its degrading enzymes ADAMTS-4 and ADAMTS-5 is implicated in the development of IDD. Here, we investigated the effect of leptin, a hormone with increased circulating levels in obesity, on the expression of aggrecan and ADAMTSs in primary human nucleus pulposus (NP) cells. Real-time PCR and Western blots showed that leptin increased the mRNA and protein expression of ADAMTS-4 and ADAMTS-5 and reduced the level of aggrecan in NP cells, accompanied by a prominent induction of p38 phosphorylation. Treatment of NP cells with SB203580 (a p38 inhibitor) abolished the regulation of aggrecan and ADAMTSs by leptin. Knockdown of ADAMTS-4 and ADAMTS-5 by siRNAs also attenuated the degradation of aggrecan in leptin-stimulated NP cells. To conclude, we demonstrated that leptin induces p38 to upregulate ADAMTSs and thereby promoting aggrecan degradation in human NP cells. These results provide a novel mechanistic insight into the molecular pathogenesis of obesity-associated IDD.

Vitamin A Deficiency Induces Congenital Spinal Deformities in Rats

Most cases of congenital spinal deformities were sporadic and without strong evidence of heritability. The etiology of congenital spinal deformities is still elusive and assumed to be multi-factorial. The current study seeks to elucidate the effect of maternal vitamin A deficiency and the production of congenital spinal deformities in the offsping. Thirty two female rats were randomized into two groups: control group, which was fed a normal diet; vitamin A deficient group, which were given vitamin A-deficient diet from at least 2 weeks before mating till delivery. Three random neonatal rats from each group were killed the next day of parturition. Female rats were fed an AIN-93G diet sufficient in vitamin A to feed the rest of neonates for two weeks until euthanasia. Serum levels of vitamin A were assessed in the adult and filial rats. Anteroposterior (AP) spine radiographs were obtained at week 2 after delivery to evaluate the presence of the skeletal abnormalities especially of spinal deformities. Liver and vertebral body expression of retinaldehyde dehydrogenase (RALDHs) and RARs mRNA was assessed by reverse transcription-real time PCR. VAD neonates displayed many skeletal malformations in the cervical, thoracic, the pelvic and sacral and limbs regions. The incidence of congenital scoliosis was 13.79% (8/58) in the filial rats of vitamin A deficiency group and 0% in the control group. Furthermore, vitamin A deficiency negatively regulate the liver and verterbral body mRNA levels of RALDH1, RALDH2, RALDH3, RAR-α, RAR-β and RAR-γ. Vitamin A deficiency in pregnancy may induce congenital spinal deformities in the postnatal rats. The decreases of RALDHs and RARs mRNA expression induced by vitamin A deprivation suggest that vertebral birth defects may be caused by a defect in RA signaling pathway during somitogenesis.

Evaluation of quality of life in adolescent idiopathic scoliosis with different distal fusion level: a comparison of L3 versus L4.

Study Design: Retrospective case-control study. Objective: The aim of this study was to assess patients’ quality of life with different fusion levels in posterior pedicle screw correction of idiopathic scoliosis. Summary of Background Data: No previous study has demonstrated differences in health-related quality of life (HRQoL) between patients fused to L3 versus L4. Materials and Methods: A retrospective study was conducted on 30 scoliotic patients fused to L3 using complete pedicle screw instruments. Thirty age-matched and sex-matched scoliotic patients fused to L4 were in the control group. Radiologic parameters were assessed before surgery and at latest follow-up between the 2 groups. These 2 groups were compared for the Scoliosis Research Society 22 questionnaire (SRS-22), Oswestry Disability Index (ODI), visual analogue scale (VAS), and Short Form-36 (SF-36) questionnaires, which were administered preoperatively and at final follow-up. Results: There were no significant differences in sex, age, follow-up duration, the distribution of curve patterns, the postoperative residual Cobb angle of the main curve, complications, or surgical method between the L3 and L4 groups (P>0.05). Preoperative scores were statistically similar in the L3 and L4 groups for all domains of all questionnaires. There was no difference between the L3 and L4 groups for ODI (P=0.527) and VAS (P=0.518). There were no significant differences in the scores on function/activity, self-image/appearance, pain, mental health, or satisfaction with treatment domains between the 2 groups. No significant differences between the 2 groups were found at the final follow-up in the SF-36 subscales/domain scores. Conclusions: This study attempted to elucidate the correlation between the length of fusion and functional outcome; however, it could not identify any difference between different fusion levels. On the basis of short-term results, there were no significant differences in the questionnaire scores between the 2 groups.

Rib deformities in congenital scoliosis.

Study Design. Retrospective review. Objective. To identify the incidence and characteristics of rib anomalies in patients with congenital scoliosis (CS) in a Chinese population. Summary of Background Data. Rib deformities and intraspinal anomalies often coexist in individuals with CS. Rib deformities may assist in diagnosing occult anomalies in these patients. The incidence of rib anomalies and the relationship between rib and vertebral abnormalities in Chinese patients with CS have not been reported. Methods. A total of 382 patients operated on at Peking Union Medical College Hospital during January 2010 to October 2012 were identified from a single institutional database. The demographic distribution, clinical and radiographical data were collected to investigate the incidence of rib anomalies, and the vertebral and intraspinal abnormalities associated with it. Results. A total of 192 patients (50.3%) were documented with rib anomalies including numerical variation (46.4%) and structural changes (72.4%). Missing ribs was the most commonly seen anomaly in these patients, accounting for 43.8% of the rib anomalies. Of the patients with rib anomalies, a slightly higher proportion of patients had simple anomalies, 106 (55.2%) versus 86 (44.8%). Rib changes were most common in patients with thoracic or thoracolumbar vertebral anomalies, and occurred most frequently on the concave side (65.5%) or in the lower thoracic spine (36.5%). The overall incidence rate of intraspinal anomalies was 40.1% (153/382), and these were most commonly seen in patients with thoracic vertebral anomalies or with upper and middle thoracic rib anomalies. Conclusion. The incidence of rib anomalies was 50.3% in surgical patients with CS. The rib anomalies vary with the location and type of vertebral anomalies. The incidence of intraspinal anomalies was significantly higher in patients with rib anomalies than in those without rib anomalies. Level of Evidence: 4

Comparative analysis of serum proteomes of degenerative scoliosis

Degenerative scoliosis (DS) is an important degenerative lumbar disease causing spinal dysfunction and affecting the quality of life of the elderly, and is associated not only with severe back or leg pain but also with complicated surgical outcomes. The pathogenesis of DS is still unknown. Therefore, it is very important to ascertain the etiology of degenerative scoliosis and establish related molecular markers predicting and controlling the scoliosis. For the first time, we used two‐dimensional fluorescence DIGE to compare the serum proteome profiles of 12 DS patients and controls. Proteins found to be differentially expressed were identified by MALDI‐TOF mass spectrometric analysis, coupled with database interrogation. Eleven spots that were differentially expressed in the sera of DS patients were found, and eight gene products were identified among these spots. Clusterin, CLU cDNA FLJ57622, ALB cDNA FLJ50830, Hypothetical short protein, HLA‐A MHC class 1 antigen. (Fragment), ALB 23 kDa protein, Isoform 1 of G protein‐regulated inducer of neurite outgrowth 1 (GPRIN I)and Ficolin‐3 were down‐regulated in the sera of DS patients. The decreased levels of Clusterin and Ficolin‐3 were confirmed by Western blot. The information obtained with this proteomic analysis will be very useful in understanding the pathophysiology of DS as well as in finding candidates as drug targets of DS. These results may provide a novel approach for the pathogenesis study of DS.

Unplanned Reoperation within 30 Days of Fusion Surgery for Spinal Deformity

No recent studies have analyzed the rates of or reasons for unanticipated revision surgery within 30 days of primary surgery in spinal deformity patients. Our aim was to examine the incidence, characteristics, reasons, and risk factors for unplanned revision surgery in spinal deformity patients treated at one institution. All patients with a diagnosis of spinal deformity presenting for primary instrumented spinal fusion at a single institution from 1998 to 2012 were reviewed. All unplanned reoperations performed within 30 days after primary surgery were analyzed in terms of demographics, surgical data, and complications. Statistical analyses were performed to obtain correlations and risk factors for anticipated revision. Of 2758 patients [aged 16.07 years (range, 2–71), 69.8% female] who underwent spinal fusion surgery, 59 (2.1%) required reoperation within 30 days after primary surgery. The length of follow up for each patient was more than 30 days. Of those that required reoperation, 87.0% had posterior surgery only, 5.7% had anterior surgery, and 7.3% underwent an anteroposterior approach. The reasons for reoperation included implant failure (n = 20), wound infection (n = 12), neurologic deficit (n = 9), pulmonary complications (n = 17), and coronal plane imbalance (n = 1). The risk factors for reoperation were age, diagnosis, and surgical procedure with osteotomy.