Long non-coding RNA CIR inhibits chondrogenic differentiation of mesenchymal stem cells by epigenetically suppressing ATOH8 via methyltransferase EZH2.

BACKGROUND: Osteoarthritis (OA) is the most common articular disorder, leading to joint malfunction and disability. Although the incidence of OA is increasing globally, the treatment of OA is very limited. LncRNA CIR has been implicated in OA through unclear mechanisms. Here, we investigated the role of lncRNA CIR in chondrogenic differentiation. METHODS: Human umbilical-cord-derived mesenchymal stem cells (hUC-MSCs) were obtained from human umbilical cords. Flow cytometry was used to analyze the surface markers of hUC-MSCs. Various culture conditions and corresponding staining assays were employed to assess the differentiation abilities of hUC-MSC. qRT-PCR, western blot, and immunostaining were used to measure expression levels of related genes and proteins such as lncRNA CIR, ATOH8, EZH2, and H3K27me3. RNA immunoprecipitation assay, biotin pull-down, and chromatin immunoprecipitaion assay were performed to analyze the interactions of lncRNA CIR, EZH2, H3K27me3 and ATOH8 promoter. RESULTS: hUC-MSCs exhibited MSCs features and could differentiate into chondrocytes under specific conditions. LncRNA CIR was downregulated while ATOH8 was upregulated during the chondrogenic differentiation of hUC-MSCs. Knockdown lncRNA CIR or overexpression of ATOH8 promoted chondrogenic differentiation. Further, lncRNA CIR bound to EZH2 and repressed ATOH8 expression via EZH2-mediated H3K27me3, which promotes the methylation of ATOH8. Inhibition of ATOH8 reversed the effects of knockdown lncRNA CIR on chondrogenic differentiation. CONCLUSION: LncRNA CIR suppresses chondrogenic differentiation of hUC-MSCs. Mechanistically, lncRNA CIR could inhibit ATOH8 expression that functions to promote chondrogenic differentiation through EZH2-mediated epigenetic modifications.

A Modified Technique to Improve Reliability of Distally Based Sural Fasciocutaneous Flap for Reconstruction of Soft Tissue Defects Longitudinal in Distal Pretibial Region or Transverse in Heel and Ankle.

Partial flap loss is a common complication of the distally based sural fasciocutaneous flap. We present a modified technique of a sloped skin island design to improve the reliability of the flap when used to reconstruct a longitudinal distal pretibial defect or transverse heel and ankle defect. Thirty-one flaps with the slope-designed skin island were used to reconstruct such defects in 30 patients. In the modified technique, the skin island was rotated toward the vascular axis of the flap. The defects were located in the distal pretibial region in 7 cases and the ankle and heel region in 24. The horizontal dimension of the skin island decreased by an average of 5.6 (range 2.5 to 14.8) cm with the sloped design, and the rotation angle varied from 42° to 90° (mean 69°). Of the 31 flaps, 29 survived, 1 developed marginal necrosis, and 1 developed lateral partial necrosis. The sloped design of the skin island is applicable to reconstruction of longitudinal distal pretibial or transverse heel and ankle defects. The modified technique can decrease the horizontal dimension and increase perfusion of the skin island, thus improving the reliability of the flap.

iNOS expression and osteocyte apoptosis in idiopathic, non-traumatic osteonecrosis.

BACKGROUND AND PURPOSE: Non-traumatic osteonecrosis is a progressive disease with multiple etiologies. It affects younger individuals more and more, often leading to total hip arthroplasty. We investigated whether there is a correlation between inducible nitric oxide synthase (iNOS) expression and osteocyte apoptosis in non-traumatic osteonecrosis. PATIENTS AND METHODS: We collected and studied 20 human idiopathic, non-traumatic osteonecrosis femoral heads. Subchondral bone samples in the non-sclerotic region (n = 30), collected from osteoarthritis patients, were used as controls. Spontaneously hypertensive rats were used as a model for osteonecrosis in the study. We used scanning electron microscopy, TUNEL assay, and immunohistochemical staining to study osteocyte changes and apoptosis. RESULTS: The morphology of osteocytes in the areas close to the necrotic region changed and the number of apoptotic osteocytes increased in comparison with the same region in control groups. The expression of iNOS and cytochrome C in osteocytes increased while Bax expression was not detectable in osteonecrosis samples. Using spontaneously hypertensive rats, we found a positive correlation between iNOS expression and osteocyte apoptosis in the osteonecrotic region. iNOS inhibitor (aminoguanidine) added to the drinking water for 5 weeks reduced the production of iNOS and osteonecrosis compared to a control group without aminoguanidine. INTERPRETATION: Our findings show that increased iNOS expression can lead to osteocyte apopotosis in idiopathic, non-traumatic osteonecrosis and that an iNOS inhibitor may prevent the progression of the disease.

Distally based perforator-plus sural fasciocutaneous flap for soft-tissue reconstruction of the distal lower leg, ankle, and foot: comparison between pediatric and adult patients.

There are no large series comparing the distally based perforator-plus sural fasciocutaneous flap used in pediatric and adult populations. The flaps were divided into two groups: the children (patient's age<14 years) group (n=53) and the adults (patient's age ≥ 18 years) group (n=148). We compared flap-viability-related complications and their potential risk factors. In the patients with at least 12-month postoperative follow-up, the reconstruction outcomes, donor-site morbidities, and transitory and permanent swelling of the affected lower limb were compared. Partial necrosis, marginal necrosis, and overall complication rates were 13.2, 3.8, and 17.0% in the pediatric group, and 12.2, 1.4, and 13.6% in the adult group, respectively; the differences were not statistically significant (p>0.05). Incidences of hypertrophic scar and pruritus at the donor site were significantly higher, while incidence of transitory swelling of the affected lower limb was significantly lower in the pediatric group. This flap in children is similar to that in adults in the reliability.

The BRD4-SRPK2-SRSF2 signal modulates the splicing efficiency of ACSL3 pre-mRNA and influences erastin-induced ferroptosis in osteosarcoma cells.

Lipid metabolism is the key to ferroptosis susceptibility. However, little is known about the underlying mechanisms in osteosarcoma cells. Functional restriction of bromodomain-containing protein 4 (BRD4) reduced the susceptibility to erastin-induced ferroptosis of osteosarcoma cells both in vitro and in vivo. Mechanically, BRD4 controls the splicing efficiency of the RNA precursor (pre-mACSL3) of ACSL3 (ACSL3) by recruiting serinerich/threonine protein kinase 2 (SRPK2) to assemble the splicing catalytic platform. Moreover, the AMP-binding domain of ACSL3 significantly influences arachidonic acid synthesis and thus determines the susceptibility to erastin-induced ferroptosis. Overall, we found a BRD4-mediated pre-mACSL3 splicing influences erastin-induced ferroptosis by affecting arachidonic acid synthesis in osteosarcoma cells. Data in this study fills some of the gap in understanding the post-transcriptional regulatory mechanisms of ACSL3 and provides new insights into the mechanisms of lipid metabolism regulation and its effect on susceptibility to ferroptosis in osteosarcoma cells.

Anterograde-retrograde method for harvest of distally based sural fasciocutaneous flap: report of results from 154 patients.

Distally based sural fasciocutaneous flap is traditionally raised by the retrograde method. This article introduces the anterograde-retrograde method for harvest of the flap and describes our experience on altering the flap plan. A total of 159 flaps in 154 patients were elevated by the anterograde-retrograde approach that harvest of the flap began with exploring the peroneal artery perforators nearby the pivot point before the upper and bilateral edges of the flap were incised. Partial necrosis occurred in 16 (10.1%) flaps, and marginal necrosis developed in 10 flaps. Nine flaps were redesigned with adjusted pivot point and skin island. The anterograde-retrograde approach for harvest of the flap can accurately locate the perforator, readily adjust both the pivot point and skin island if necessary, and thus improve reliability of the flap. This approach is particularly applicable for elevation of the flap without preoperative localization of the perforators by means of the Doppler.

Old unreduced obturator dislocation of the hip: A case report.

BACKGROUND: Obturator dislocation is a rare type of hip dislocation, accounting for about 2%-5% of all hip dislocations. The occurrence of old unreduced obturator dislocation is even more infrequent, with only 17 cases reported in nine studies, most of which were from the 1950s to 1980s in developing countries. CASE SUMMARY: A 38-year-old woman from Hunan Province, China presented with stiffness of the left hip in abduction, flexion, and external rotation after falling from a 2-meter-tall tree onto her left knee 1.5 mo prior. Pelvic radiograph and computed tomography revealed obturator dislocation of the left hip accompanied by impaction fracture at the superolateral aspect of the left femoral head without associated acetabulum fracture. Open reduction was performed, resulting in restoration of the concentric alignment of the left hip. After surgery, 6-wk skin traction was applied and the patient was kept in bed for an additional 2 wk. At 3 mo after surgery, the patient reported experiencing some pain, which did not affect the function of the affected limb, and some movement restriction but no abduction deformity or claudication was present. An X-ray showed that the left hip was homocentric, and there was no sign of posttraumatic arthritis or avascular necrosis. CONCLUSION: Open reduction may be an effective treatment strategy for the rare condition of old unreduced obturator dislocation with short neglect time.

LncRNA TDRG1 Promotes Proliferation, Invasion and Epithelial-Mesenchymal Transformation of Osteosarcoma Through PI3K/AKT Signal Pathway.

OBJECTIVE: This study aimed to investigate the effect of long non-coding TDRG1 on proliferation and migration of osteosarcoma cells through PI3K/AKT signaling pathway. MATERIALS AND METHODS: Altogether 87 cases of osteosarcoma tissues and adjacent tissues were collected, and osteosarcoma cells and osteoblasts were purchased. The expression of LncRNA TDRG1 in tissues and cells was detected by RT-PCR. Si-NC, si-TDRG1, and Sh-TDRG1 were transfected into osteosarcoma cells. L740Y-P (activator of PI3K/AKT pathway) and LY294002 (inhibitor of PI3k/AKT pathway) were used to interfere with PI3k/Akt signaling pathway in osteosarcoma cells. qRT-PCR was used to detect the expression of TDRG1 in osteosarcoma tissues and cells. WB was used to detect the expression of p-PI3K, p-AKT, N-cadherin, E-Cadherin, vimentin, Bax, Caspase-3, and Bcl-2 in cells. CCK-8, Transwell and cell scratch tests were used to detect cell proliferation, invasion and migration, and flow cytometry was used to detect cell apoptosis. RESULTS: TDRG1 was highly expressed in osteosarcoma, and the levels of p-PI3K and p-AKT were also up-regulated. Cell experiments showed that inhibiting the expression of TDRG1 could inhibit the proliferation, invasion, migration and EMT of osteosarcoma cells, promote the apoptosis of cells, and up-regulating the expression of TDRG1 could promote the proliferation, invasion, migration and EMT of osteosarcoma cells and inhibit the apoptosis of cells. The 740Y-P intervention could reverse the inhibition of Si-TDRG1 on osteosarcoma cell proliferation, invasion, migration and EMT and the promotion of cell apoptosis. LY294002 intervention could reverse the promotion of Sh-TDRG1 on osteosarcoma cell proliferation, invasion, migration and EMT and the inhibition of cell apoptosis. CONCLUSION: TDRG1 is highly expressed in osteosarcoma tissue. Silencing the expression of osteosarcoma can inhibit the proliferation, invasion, migration and EMT of osteosarcoma cells by inhibiting PI3K/AKT signaling pathway, which may be a new target for diagnosis and treatment of osteosarcoma.

Unusual presentation of congenital radioulnar synostosis with osteoporosis, fragility fracture and nonunion: A case report and review of literature.

BACKGROUND: Congenital radioulnar synostosis (CRUS) is a rare deformity of the upper extremity. It is characterized by loss of rotation of the involved forearm and functional limitations in daily activities. No studies on CRUS with osteoporosis have been reported to date, and osteoporosis is usually recognized as an important dimension of genetic disorder in children. We discuss the possible relationship among this disorder, osteoporosis and fracture nonunion, investigate the strict surgical indications and recommended treatments. CASE SUMMARY: A 14-year-old male patient with bilateral CRUS with osteoporosis, fragility fracture and nonunion of fractures in ulna and radius presented our institution for further treatment, complaining of limitation in rotation. The bone mineral density of the hip and lumbar spine was 0.687 g/cm2 and 0.705 g/cm2, respectively, and the Z-score for both was -2.1, which revealed osteoporosis and a high risk of fracture. Tow serum bone turnover markers indicated an imbalance of bone metabolism. Reoperation for ulna fracture with autogenous bone grafting and a postoperative physiotherapy program were adopted rather than the separation of pathological synostosis. Radiological examination, observational posture assessment and limb function scale were evaluated before and 1 year after surgery. At 1 year, the fracture nonunion had almost recovered, forearm movement function on the fracture side was restored, and function on the healthy side was significantly improved compared with that before rehabilitation. CONCLUSION: Surgical indications for CRUS vary from person to person. Surgery should not be the first choice of treatment, and physiotherapy is not inferior to surgical treatment.

LncRNA-MALAT1 promotes osteogenic differentiation through regulating ATF4 by sponging miR-214: Implication of steroid-induced avascular necrosis of the femoral head.

OBJECTIVE: To study roles oflncRNA-MALAT1 and miR-214 in steroid-induced avascular necrosis of the femoral head (SANFH). METHODS: MALAT1, miR-214 andosteogenic-relatedgenes(Runx2, ALP, andOCN)expressions were determined in SANFH tissue samples and human bone marrow stromal cells (BMSC) by RT-qPCR. BMSCs were verifiedbyflowcytometry. The ATF4 level was determined by western blotting and RT-qPCR. Osteogenesis inducedbyosteogenic medium (OM) in BMSCs and dexamethasone (DEX) was used to inhibit osteogenesis. The alkaline phosphatase (ALP) activity was measured and ALP staining and alizarin red staining were conducted for evaluation of osteogenic differentiation. MTT assay was used for cell proliferation. The dual luciferase reporter assay was used to confirm binding between MALAT1 and miR-214, as well as miR-214 and ATF4. RESULTS: MALAT1 was down-regulated and miR-214 was up-regulated in SANFH tissues. DEX inhibited osteogenic differentiation of BMSC in a dose-dependent manner, leading to decreased MALAT1, increased miR-214, as well as reduced ALP activity and decreased expression of RUNX2, ALP and OCN. Either overexpression of MALAT1 or inhibition of miR-214 improved DEX-induced inhibition of BMSC osteogenic differentiation. The overexpression of miR-214 reversed the effects by MALAT1. MALAT1 directly sponged miR-214 and miR-214 directly targeted ATF4. CONCLUSION: MALAT1 was down-regulated, while miR-214 was elevated in SANFH tissues. MALAT1 promoted osteogenesis differentiation by sponging miR-214 to upregulate ATF4.

Modified pararectus approach for treatment of atypical acetabular anterior wall fracture: A case report.

BACKGROUND: Acetabular anterior wall fracture with preservation of the pelvic brim is extremely rare. It is different from anterior wall fracture classified by Judet and Letournel. Few studies have reported cases treated by open reduction and internal fixation via the Smith-Petersen or iliofemoral approach. CASE SUMMARY: We report a 48-year-old Chinese woman who had difficulty moving her right hip from abduction and external rotation after falling from 3 m. Pelvic radiograph and three-dimensional reconstruction of computed tomography revealed acetabular anterior wall fractures combined with fractures of the anterior inferior iliac spine and the iliac wing but not involving the pelvic brim. First, the patient underwent interim management by closed reduction of the hip dislocation and skin traction for 6 d. Then, we used a modified pararectus approach for treatment to fix the acetabular fractures with a reconstruction plate and nonlocking T-shape plate. At the 9-mo follow-up, the patient could walk painlessly without necrosis of the femoral head or heterotopic ossification, and the X-rays and computed tomography scan reconstructions showed good bone union. CONCLUSION: The modified pararectus approach described here can facilitate exposure, reduction, and osteosynthesis for atypical acetabular fracture with less invasiveness.

The Sp1/FOXC1/HOTTIP/LATS2/YAP/ß-catenin cascade promotes malignant and metastatic progression of osteosarcoma.

The prognosis for osteosarcoma (OS) is dismal due to the aggressive tumor growth and high incidence of metastasis. The long noncoding RNA human homeobox A transcript at the distal tip (HOTTIP) and the transcription factor forkhead box C1 (FOXC1) present oncogenic activities in OS. Here, we aimed at gaining insights into the underlying mechanisms and their crosstalk. The expression of FOXC1 and HOTTIP in OS tissues or cell lines was examined by real-time PCR (RT-PCR) and western blot. The in vitro effects of FOXC1 or HOTTIP on cell viability, proliferation, migration, invasion, and expression of target genes were examined using MTT, colony-forming assay, wound-healing, Transwell invasion, and western blot, respectively; the in vivo effects were examined using xenograft and experimental metastasis models. Molecular control of HOTTIP on large tumor suppressor 2 (LATS2) or transactivation of FOXC1 or Sp1 on HOTTIP was assessed by combining RNA immunoprecipitation, qRT-PCR, western blot, ChIP, and luciferase assay. Both FOXC1 and HOTTIP were potently up-regulated in OS tissues and cell lines. FOXC1 and HOTTIP essentially maintained viability, proliferation, migration, and invasion of OS cells in vitro and contributed to xenograft growth or lung metastasis in vivo. Mechanistically, HOTTIP recruited enhancer of zeste homolog 2 (EZH2) and lysine-specific demethylase 1 (LSD1) to silence LATS2 and thus activated YAP/ß-catenin signaling. Upstream, Sp1 activated FOXC1 and they both directly transactivated HOTTIP. In summary, we showed that the Sp1/FOXC1/HOTTIP/LATS2/YAP/ß-catenin cascade presented oncogenic activities in OS cells. Targeting FOXC1 or HOTTIP may therefore prove beneficial for OS treatment.

Multiple rare causes of post-traumatic elbow stiffness in an adolescent patient: A case report and review of literature.

BACKGROUND: Joint stiffness after elbow surgery is not a rare complication, and is always accompanied by deformity. The causes of joint stiffness are multiple in different patients, and divided into intrinsic and extrinsic causes. Herein, we report an unusual case of posttraumatic elbow stiffness due to multiple and rare causes. CASE SUMMARY: A 19-year-old male was hospitalized with the loss of motion of the left elbow for over ten years. Left limb computed tomography revealed left elbow stiffness with bony block and connection. The patient underwent surgery, and the etiology of joint stiffness was found to be a rare combination of common and uncommon causes. During an 18-mo follow-up period, the patient's left elbow had normal motion and he was symptom-free. CONCLUSION: However, this case combined with multiple and rare causes highlights that the patient with scar physique is likely to be accompanied with more severe soft tissue, nerve contracture, and heterotypic ossification, even during recurrence.

MicroRNA-29a suppresses the invasion and migration of osteosarcoma cells by regulating the SOCS1/NF-κB signalling pathway through negatively targeting DNMT3B.

The present study aimed to investigate the roles of the microRNA­29a/DNA methyltransferase 3B/suppressor of cytokine signalling 1 (miR­29a/DNMT3B/SOCS1) axis in the invasion and the migration of osteosarcoma (OS). The expression levels of miR­29a, DNMT3B and SOCS1 were determined in tissue samples and OS cell lines by reverse transcription­quantitative polymerase chain reaction (PCR). Apoptosis was measured using flow cytometry analysis. Transwell and wound healing assays were conducted to measure the invasion and migration abilities of OS cells, respectively. A dual­luciferase reporter assay was also conducted to determine the interaction between DNMT3B and miR­29a, while methylation­specific PCR was used to detect the methylation of SOCS1. Western blotting was performed to determine the protein levels of DNMT3B and SOCS1, as well as the levels of proteins associated with epithelial­mesenchymal transition (EMT), apoptosis and the nuclear factor (NF)­κB signalling pathway. The results demonstrated that miR­29a and SOCS1 were downregulated, and DNMT3B was upregulated in both OS tissues and cell lines. The expression of miR­29a and SOCS1 was found to be associated with advanced clinical stage and distant metastasis. In addition, the dual­luciferase reporter assay revealed that DNMT3B was a direct target of miR­29a. Overexpression using miR­29a mimics decreased DNMT3B expression and the methylation level of SOCS1, which resulted in the upregulation of SOCS1 in U2OS and MG­63 cells, while miR­29a inhibition led to the opposite results. Transfection with miR­29a mimics also promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells, while it markedly reduced the nuclear translocation of p65 and IκB­α degradation. Treatment with 5­aza­2'­deoxycytidine worked together with miR­29a mimics to synergistically enhance the aforementioned effects. By contrast, the effects induced by miR­29a were partly reversed upon co­transfection with SOCS1 siRNA. In conclusion, miR­29a promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells via inhibition of the SOCS1/NF­κB signalling pathway by directly targeting DNMT3B.

Cellular and molecular responses in progressive pseudorheumatoid dysplasia articular cartilage associated with compound heterozygous WISP3 gene mutation.

Progressive pseudorheumatoid dysplasia (PPD) is characterized by continuous degeneration and loss of articular cartilage, which has been attributed to mutations in the gene encoding WISP3. We collected a PPD family and analyzed their WISP3 genes mutation. Articular chondrocytes (ACs) were purified from the femurs of a PPD patient after hip replacement surgery. Cell growth, proliferation, and viability were examined. Gene expression profiling and analyses of matrix metalloproteinases (MMP)-1, -3, and -13 proteins were carried out using cDNA differential microarrays, real-time reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot analysis. We found that two probands carried a deletion (840delT) mutation in maternal allele, which leads to truncated WISP3 protein missing 43 residues in C terminus; and a 1000T>C substitution in paternal allele, which was also passed on to four other members in the PPD kindred. PPD ACs were heterogeneous in size with an enhanced rate of cell proliferation and viability compared with the normal ACs. MMP-1, -3, and -13 mRNA expressions were dereased in PPD ACs. MMP-1, -3, and -13 protein levels, however, were increased in cell lysates from PPD ACs, but markedly decreased in the supernatants from cultured ACs. WISP3 mRNA expression in PPD ACs was also decreased. Our results show, for the first time, a compound heterozygous mutation of WISP3 and a series of cellular and molecular changes disturbing the endochondral ossification in this PPD patient.

[Treatment of fractures of extremities with expandable intramedullary nails].

OBJECTIVE: To investigate the method and clinical effect of the expandable intramedullary nails on fractures of extremities. METHODS: Nineteen cases of extremities long tubular bone fractures were treated with Fixion expandable intramedullary nails. RESULTS: Nineteen cases were followed up for 4-18 months,all cases healed without any complications. CONCLUSION: The application of expandable intramedullary nails in the treatment of extremity fractures has the advantages of little trauma, simple operation, rigid fixation and high healing rate. It is a good treatment for fractures of extremities.

A case report of Schatzker type VI tibial plateau fracture treated with double reverse traction closed reduction combined with minimally invasive percutaneous plate osteosynthesis technique: A case report.

RATIONALE: The knee joint is an important weight-bearing joint, tibial plateau fractures affect knee function and stability. High-energy intra-articular fractures involving the tibial plateau can cause management-related problems such as wound dehiscence; severe comminution leading to malalignment; and delayed complications such as varus collapse, implant failure, and arthritis of the knee joint. The treatment of severe or complex tibial plateau fractures can be quite difficult. Traditional methods of open reduction and plating require extensive exposures, which may further compromise soft tissue and devascularize bone fragments, leading to infection. In this case, a novel device, double reverse traction combined with MIPPO technique, was used and provided the possibility of minimally invasive and personalized orthopedic surgery to treat severe comminuted Schatzker type VI tibial plateau fracture and tibial shaft fracture and got satisfactory results. PATIENT CONCERNS: A previously healthy 56-year-old man presented to the emergency room after a fall from a height, who lost the movement of the left knee with pain and swelling. DIAGNOSES: X-rays showed a tibial plateau comminuted fracture, Schatzker type VI, and tibial shaft fracture. INTERVENTIONS: Applying less extensile exposure and the indirect reduction technique of double reverse traction and closed reduction combined with minimally invasive percutaneous plate osteosynthesis (MIPPO) technique, we got satisfactory recovery of the severe comminuted Schatzker type VI tibial plateau fracture and tibial shaft fracture. OUTCOMES: This severe comminuted fracture and tibial shaft fracture were successfully reduced and got satisfactory recovery of knee joint function. LESSONS: Double reverse traction combined with MIPPO technique can reduce the risk of surgical complications, such as bleeding, oozing, and wound infection. It can be applied in patients with comorbidities such as cardiac disease, hypertension, and heart failure who may otherwise not be candidates for surgery. The cost burden is lower than that of the traditional traction table.

[Characterization of biologic behaviors and cDNA expression of articular chondrocytes in spondyloepiphyseal dysplasia tarda with progressive arthropathy].

OBJECTIVE: Spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA) is an autosomal-recessive hereditary disorder of cartilage homeostasis. The pathogenesis of SEDT-PA is unknown though it has been demonstrated that CCN6 is the SEDT-PA causing gene. The present study characterized the biologic behaviors and cDNA differential expression profile of articular chondrocytes in SEDT-PA. METHODS: The morphologic and functional features of growth, proliferation, differentiation and DNA synthesis of SEDT-PA chondrocytes were determined with cell growth curve, (3)H-TDR incorporation, MTT and flow cytometry. cDNA differential expression profile was carried out with gene microarray containing 8000 genes. Differentially expressed genes were verified by RT-PCR, Western blot and immunohistochemistry. RESULTS: As compared with normal control, the variant chondrocytes were much larger in size with an enhanced ability of proliferation and DNA synthesis and increased ratio of G(2)-M (10.72% vs 0.11%) to S phases (37.0% vs 15.8%). Matrix metalloproteinases (MMPs), which decompose the extra-cellular matrix of the cartilage, accumulated at the endochylema and failed in exocytosis, which lead to the negative feedback of the mRNA transcriptions. The mRNA expression of MMPs was down-regulated. At the same time, the mRNA expression of genes related to cell growth, proliferation and progression of cell cycles were up-regulated, while most of those associated with extracellular matrix, non-collagen proteins and poly-proteoglycans were down-regulated. CONCLUSIONS: The accumulation and failure in exocytosis of the MMPs decompose the extra-cellular matrix of the cartilage. The decreased expression of matrix proteins and polyproteoglycans is involved in the pathogenesis of arthropathy resulted from CCN6 mutation.

[Proliferation, differentiation, and gene expression profile of osteoblast of patient with spondyloepiphyseal dysplasia tarda with progressive arthropathy].

OBJECTIVE: To explore the proliferation, differentiation, and gene expression profile of the osteoblasts (OBs) of patient with spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA). METHODS: OBs from the head of femur of a SEDT-PA patient resected during operation were cultured. ELISA was used to examine the bone-specific alkaline phosphatase (BAP), osteocalcin (OC), and osteoprotegrin (OPC) in the lysate of OBs. The proliferation and survival of the OBs were evaluated with MTT method and (3)H-TDR incorporation. Flow cytometry was used to observe the cell cycle. Northern blotting was used to evaluate the mRNA expression of WISP3, a member of the CCN family, mRNA in the OBs. Gene differential expression microarray was used to determine the cDNA expression. Osteoblasts from the head of femur of a patient about the same age with fracture of femur neck was used as control. RESULTS: The cultured OBs from the SEDT-PA patient showed a higher survival capacity (0.86 +/- 0.04 vs 0.71 +/- 0.10) and more (3)H-TDR incorporation (1363 +/- 350 vs 867 +/- 128). The expressions of OC and OPG were down-regulated to the 1/4.3 and 1/4.69 of the control respectively. There was no significant difference in the expression of BAP. WISP3 was very lowly expressed in the OBs of the SEDT-PA patient. In comparison with the normal control, there were up-regulation of 22 genes, including those coding chemotactic factors and inflammatory factors, and down-regulation of 16 genes in the OBs of the SEDT-PA patient with a synthetic effect of more rapid proliferation of OBs and reduction of synthesis of extracellular matrix, resulting in osteopenia. CONCLUSION: Not significantly different between SEDT-PA patient and normal person, the WISP3 expression may not be a direct factor of SEDT-PA.

Comments on Bu et al. "P16(INK4a) overexpression and survival in osteosarcoma patients: a meta analysis".

Recently, we read the article "P16(INK4a) overexpression and survival in osteosarcoma patients: a meta analysis" by Jie Bu and his colleagues, published in the recent issue of International Journal Of Experimental Pathology. This research performed a meta-analysis to uncover the role of P16(INK4a) expression in overall survival rate in patients with osteosarcoma. The investigators concluded as follows: (i) the pateints with overexpression of P16(INK4a) had a longer overall survival rate than that with loss expression of P16(INK4a); (ii) P16(INK4a) was an effective biomarker of prognosis in patients with osteosarcoma.The findings are valubale and encouraging. However, some flaws and imperfections rooted in this work.