Gorham-Stout case report: a multi-omic analysis reveals recurrent fusions as new potential drivers of the disease.

BACKGROUND: Gorham-Stout disease is a rare condition characterized by vascular proliferation and the massive destruction of bone tissue. With less than 400 cases in the literature of Gorham-Stout syndrome, we performed a unique study combining whole-genome sequencing and RNA-Seq to probe the genomic features and differentially expressed pathways of a presented case, revealing new possible drivers and biomarkers of the disease. CASE PRESENTATION: We present a case report of a white 45-year-old female patient with marked bone loss of the left humerus associated with vascular proliferation, diagnosed with Gorham-Stout disease. The analysis of whole-genome sequencing showed a dominance of large structural DNA rearrangements. Particularly, rearrangements in chromosomes seven, twelve, and twenty could contribute to the development of the disease, especially a gene fusion involving ATG101 that could affect macroautophagy. The study of RNA-sequencing data from the patient uncovered the PI3K/AKT/mTOR pathway as the most affected signaling cascade in the Gorham-Stout lesional tissue. Furthermore, M2 macrophage infiltration was detected using immunohistochemical staining and confirmed by deconvolution of the RNA-seq expression data. CONCLUSIONS: The way that DNA and RNA aberrations lead to Gorham-Stout disease is poorly understood due to the limited number of studies focusing on this rare disease. Our study provides the first glimpse into this facet of the disease, exposing new possible therapeutic targets and facilitating the clinicopathological diagnosis of Gorham-Stout disease.

Chondrocytes from osteoarthritic cartilage of obese patients show altered adiponectin receptors expression and response to adiponectin.

Obesity and osteoarthritis (OA) are well-known comorbidities and their precise molecular interactions are still unidentified. Adiponectin, a major adipokine, known to have an anti-inflammatory effect in atherosclerosis or Type 2 Diabetes Mellitus (T2DM), has also been postulated to be pro-inflammatory in OA. This dual role of adiponectin is still not explained. The precise mechanism by which adiponectin affects cartilage and chondrocytes remains to be elucidated. In the present observational study chondrocytes from 30 patients with OA (18 females and 12 males) undergoing total knee replacement (TKR) were isolated. Expression of adiponectin receptors 1 and 2 (ADIPOR1 and ADIPOR2) was examined both at gene and protein levels in chondrocytes. The difference in adiponectin receptor expression between lean and obese patients with OA and the role of adiponectin in regulating pro-inflammatory genes (MCP-1, IL-6, and VCAM-1, MMP-1, MMP-2, and TIMP-1) has been investigated. We found that ADIPOR1 represented the most abundant adiponectin receptor in primary OA chondrocytes. ADIPOR1 and ADIPOR2 genes and ADIPOR1 protein were differently expressed in OA chondrocytes obtained from obese compared with lean patients with OA. Adiponectin induced gene expression of MCP-1, IL-6, and MMP-1 in all OA patients' chondrocytes. In contrast, VCAM-1 and MMP-2 were differently regulated by adiponectin depending on the patient's body mass index. This study suggests that adiponectin and ADIPOR1 may have important roles in the pathogenesis of cartilage degeneration in OA of obese subjects.

Analysis of Transcriptional Regulation in Bone Cells.

Transcription is a process by which the rate of RNA synthesis is regulated. Here we describe the techniques for carrying out promoter-reporter assays, electrophoretic mobility shift assays, chromosome conformation capture (3C) assays, chromatin immunoprecipitation assays, and CRISPR-Cas9 assay, five commonly used methods for studying and altering gene transcription.

The Potential of Intrinsically Magnetic Mesenchymal Stem Cells for Tissue Engineering.

The magnetization of mesenchymal stem cells (MSC) has the potential to aid tissue engineering approaches by allowing tracking, targeting, and local retention of cells at the site of tissue damage. Commonly used methods for magnetizing cells include optimizing uptake and retention of superparamagnetic iron oxide nanoparticles (SPIONs). These appear to have minimal detrimental effects on the use of MSC function as assessed by in vitro assays. The cellular content of magnetic nanoparticles (MNPs) will, however, decrease with cell proliferation and the longer-term effects on MSC function are not entirely clear. An alternative approach to magnetizing MSCs involves genetic modification by transfection with one or more genes derived from Magnetospirillum magneticum AMB-1, a magnetotactic bacterium that synthesizes single-magnetic domain crystals which are incorporated into magnetosomes. MSCs with either or mms6 and mmsF genes are followed by bio-assimilated synthesis of intracytoplasmic magnetic nanoparticles which can be imaged by magnetic resonance (MR) and which have no deleterious effects on MSC proliferation, migration, or differentiation. The stable transfection of magnetosome-associated genes in MSCs promotes assimilation of magnetic nanoparticle synthesis into mammalian cells with the potential to allow MR-based cell tracking and, through external or internal magnetic targeting approaches, enhanced site-specific retention of cells for tissue engineering.

Regional Differences Between Perisynovial and Infrapatellar Adipose Tissue Depots and Their Response to Class II and Class III Obesity in Patients With Osteoarthritis.

OBJECTIVE: Obesity is associated with an increased risk of developing osteoarthritis (OA), which is postulated to be secondary to adipose tissue-dependent inflammation. Periarticular adipose tissue depots are present in synovial joints, but the association of this tissue with OA has not been extensively explored. The aim of this study was to investigate differences in local adipose tissue depots in knees with OA and characterize the changes related to class II and class III obesity in patients with end-stage knee OA. METHODS: Synovium and the infrapatellar fat pad (IPFP) were collected during total knee replacement from 69 patients with end-stage OA. Histologic changes, changes in gene and protein expression of adiponectin, peroxisome proliferator-activated receptor γ (PPARγ), and Toll-like receptor 4 (TLR-4), and immune cell infiltration into the adipose tissue were investigated. RESULTS: IPFP and synovium adipose tissue depots differed significantly and were influenced by the patient's body mass index. Compared to adipocytes from the IPFP and synovium of lean patients, adipocytes from the IPFP of obese patients were significantly larger and the synovium of obese patients displayed marked fibrosis, increased macrophage infiltration, and higher levels of TLR4 gene expression. The adipose-related markers PPARγ in the IPFP and adiponectin and PPARγ in the synovium were expressed at lower levels in obese patients compared to lean patients. Furthermore, there were increased numbers of CD45+ hematopoietic cells, CD45+CD14+ total macrophages, and CD14+CD206+ M2-type macrophages in both the IPFP and synovial tissue of obese patients. CONCLUSION: These differences suggest that IPFP and synovium may contain 2 different white adipose tissue depots and support the theory of inflammation-induced OA in patients with class II or III obesity. These findings warrant further investigation as a potentially reversible, or at least suppressible, cause of OA in obese patients.

Biosynthesis of magnetic nanoparticles by human mesenchymal stem cells following transfection with the magnetotactic bacterial gene mms6.

The use of stem cells to support tissue repair is facilitated by loading of the therapeutic cells with magnetic nanoparticles (MNPs) enabling magnetic tracking and targeting. Current methods for magnetizing cells use artificial MNPs and have disadvantages of variable uptake, cellular cytotoxicity and loss of nanoparticles on cell division. Here we demonstrate a transgenic approach to magnetize human mesenchymal stem cells (MSCs). MSCs are genetically modified by transfection with the mms6 gene derived from Magnetospirillum magneticum AMB-1, a magnetotactic bacterium that synthesises single-magnetic domain crystals which are incorporated into magnetosomes. Following transfection of MSCs with the mms6 gene there is bio-assimilated synthesis of intracytoplasmic magnetic nanoparticles which can be imaged by MR and which have no deleterious effects on cell proliferation, migration or differentiation. The assimilation of magnetic nanoparticle synthesis into mammalian cells creates a real and compelling, cytocompatible, alternative to exogenous administration of MNPs.

Functional roles of CSPG4/NG2 in chondrosarcoma.

CSPG4/NG2 is a multifunctional transmembrane protein with limited distribution in adult tissues including articular cartilage. The purpose of this study was to investigate the possible roles of CSPG4/NG2 in chondrosarcomas and to establish whether this molecule may have potential for targeted therapy. Stable knock-down of CSPG4/NG2 in the JJ012 chondrosarcoma cell line by shRNA resulted in decreased cell proliferation and migration as well as a decrease in gene expression of the MMP (matrix metalloproteinase) 3 protease and ADAMTS4 (aggrecanase). Chondrosarcoma cells in which CSPG4/NG2 was knocked down were more sensitive to doxorubicin than wild-type cells. The results indicate that CSPG4/NG2 has roles in regulating chondrosarcoma cell function in relation to growth, spread and resistance to chemotherapy and that anti-CSPG4/NG2 therapies may have potential in the treatment of surgically unresectable chondrosarcoma.

Optineurin Negatively Regulates Osteoclast Differentiation by Modulating NF-κB and Interferon Signaling: Implications for Paget's Disease.

Paget's disease of bone (PDB) is a common disease characterized by osteoclast activation that leads to various skeletal complications. Susceptibility to PDB is mediated by a common variant at the optineurin (OPTN) locus, which is associated with reduced levels of mRNA. However, it is unclear how this leads to the development of PDB. Here, we show that OPTN acts as a negative regulator of osteoclast differentiation in vitro and that mice with a loss-of-function mutation in Optn have increased osteoclast activity and bone turnover. Osteoclasts derived from Optn mutant mice have an increase in NF-κB activation and a reduction in interferon beta expression in response to RANKL when compared to wild-type mice. These studies identify OPTN as a regulator of bone resorption and are consistent with a model whereby genetically determined reductions in OPTN expression predispose to PDB by enhancing osteoclast differentiation.

Cardiac-targeted expression of soluble fas attenuates doxorubicin-induced cardiotoxicity in mice.

Doxorubicin (Dox) is known to cause cardiomyopathy and congestive heart failure upon chronic administration. The mechanisms underlying these toxicities remain uncertain but have been attributed, at least in part, by induction of cardiac cell apoptosis. Fas ligation with its cognate ligand (FasL) induces apoptosis and activates cellular inflammatory responses associated with tissue injury. We determined whether interruption of Fas/FasL interaction by cardiac-targeted expression of soluble Fas (sFas), a competitive inhibitor of FasL, would protect against Dox chronic cardiotoxicity in mice. Wild-type (WT) and sFas transgenic mice were administrated intravenously with 4 mg/kg Dox or with an equivalent volume of saline twice a week for a total of 10 injections. There were 25% mortality in WT mice, but no death was observed in sFas mice during the period of Dox treatment. Echocardiographic evaluation revealed a significant decrease in left ventricle fractional shortening after Dox treatment in WT mice but not in sFas mice. WT mice treated with Dox developed extensive myocardial cytoplasmic vacuolization, apoptosis, and interstitial fibrosis, which were much less or absent in sFas mice. The increased inducible nitric oxide synthase expression, nitric oxide production, superoxide generation, and peroxynitrite formation after Dox treatment in WT mice were attenuated by sFas expression. sFas expression also attenuated Dox-mediated induction of proinflammatory cytokines, tumor necrosis factor-alpha, interleukin (IL)-1beta, and IL-6 in the myocardium. These observations indicate that FasL is an important mediator in Dox-associated cardiotoxicity by generating reactive oxygen and nitrogen species.

A novel CCCH-zinc finger protein family regulates proinflammatory activation of macrophages.

Activated macrophages play an important role in many inflammatory diseases. However, the molecular mechanisms controlling macrophage activation are not completely understood. Here we report that a novel CCCH-zinc finger protein family, MCPIP1, 2, 3, and 4, encoded by four genes, Zc3h12a, Zc3h12b, Zc3h12c, and Zc3h12d, respectively, regulates macrophage activation. Northern blot analysis revealed that the expression of MCPIP1 and MCPIP3 was highly induced in macrophages in response to treatment with lipopolysaccharide (LPS). Although not affecting cell surface marker expression and phagocytotic function, overexpression of MCPIP1 significantly blunted LPS-induced inflammatory cytokine and NO(2)(.) production as well as their gene expression. Conversely, short interfering RNA-mediated reduction in MCPIP1 augmented LPS-induced inflammatory gene expression. Further studies demonstrated that MCPIP1 did not directly affect the mRNA stability of tumor necrosis factor alpha and monocyte chemoattractant protein 1 (MCP-1) but strongly inhibited LPS-induced tumor necrosis factor alpha and inducible nitric-oxide synthase promoter activation. Moreover, we found that forced expression of MCPIP1 significantly inhibited LPS-induced nuclear factor-kappaB activation. These results identify MCP-induced proteins, a novel CCCH-zinc finger protein family, as negative regulators in macrophage activation and may implicate them in host immunity and inflammatory diseases.