Primary cilia elongation in response to interleukin-1 mediates the inflammatory response

Primary cilia are singular, cytoskeletal organelles present in the majority of mammalian cell types where they function as coordinating centres for mechanotransduction, Wnt and hedgehog signalling. The length of the primary cilium is proposed to modulate cilia function, governed in part by the activity of intraflagellar transport (IFT). In articular cartilage, primary cilia length is increased and hedgehog signaling activated in osteoarthritis (OA). Here, we examine primary cilia length with exposure to the quintessential inflammatory cytokine interleukin-1 (IL-1), which is up-regulated in OA. We then test the hypothesis that the cilium is involved in mediating the downstream inflammatory response. Primary chondrocytes treated with IL-1 exhibited a 50 % increase in cilia length after 3 h exposure. IL-1-induced cilia elongation was also observed in human fibroblasts. In chondrocytes, this elongation occurred via a protein kinase A (PKA)-dependent mechanism. G-protein coupled adenylate cyclase also regulated the length of chondrocyte primary cilia but not downstream of IL-1. Chondrocytes treated with IL-1 exhibit a characteristic increase in the release of the inflammatory chemokines, nitric oxide and prostaglandin E2. However, in cells with a mutation in IFT88 whereby the cilia structure is lost, this response to IL-1 was significantly attenuated and, in the case of nitric oxide, completely abolished. Inhibition of IL-1-induced cilia elongation by PKA inhibition also attenuated the chemokine response. These results suggest that cilia assembly regulates the response to inflammatory cytokines. Therefore, the cilia proteome may provide a novel therapeutic target for the treatment of inflammatory pathologies, including OA

Troublesome Heterotopic Ossification after Central Nervous System Damage: A Survey of 570 Surgeries

BACKGROUND: Heterotopic ossification (HO) is a frequent complication after central nervous system (CNS) damage but has seldom been studied. We aimed to investigate features of HO for the first time in a large sample and the rate of early recurrence of HO in terms of the time of surgery. METHODOLOGY/PRINCIPAL FINDINGS: We retrospectively analyzed data from an anonymous prospective survey of patients undergoing surgery between May 1993 and November 2009 in our institution for troublesome HO related to acquired neurological disease. Demographic and HO characteristics and neurological etiologies were recorded. For 357 consecutive patients, we collected data on 539 first surgeries for HO (129 surgeries for multiple sites). During the follow-up, recurrences requiring another surgery appeared in 31 cases (5.8% [31/539]; 95% confidence interval [CI]: 3.8%-7.8%; 27 patients). Most HO requiring surgery occurred after traumatic brain injury (199 patients [55.7%]), then spinal cord injury (86 [24.0%]), stroke (42 [11.8%]) and cerebral anoxia (30 [8.6%]). The hip was the primary site of HO (328 [60.9%]), then the elbow (115 [21.3%]), knee (77 [14.3%]) and shoulder (19 [3.5%]). For all patients, 181 of the surgeries were performed within the first year after the CNS damage, without recurrence of HO. Recurrence was not associated with etiology (p = 0.46), sex (p = 1.00), age at CNS damage (p = 0.2), multisite localization (p = 0.34), or delay to surgery (p = 0.7). CONCLUSIONS/SIGNIFICANCE: In patients with CNS damage, troublesome HO and recurrence occurs most frequently after traumatic brain injury and appears frequently in the hip and elbow. Early surgery for HO is not a factor of recurrence

Osteoprotegerin in Exosome-Like Vesicles from Human Cultured Tubular Cells and Urine

Urinary exosomes have been proposed as potential diagnostic tools. TNF superfamily cytokines and receptors may be present in exosomes and are expressed by proximal tubular cells. We have now studied the expression of selected TNF superfamily proteins in exosome-like vesicles from cultured human proximal tubular cells and human urine and have identified additional proteins in these vesicles by LC-MS/MS proteomics. Human proximal tubular cells constitutively released exosome-like vesicles that did not contain the TNF superfamily cytokines TRAIL or TWEAK. However, exosome-like vesicles contained osteoprotegerin (OPG), a TNF receptor superfamily protein, as assessed by Western blot, ELISA or selected reaction monitoring by nLC-(QQQ)MS/MS. Twenty-one additional proteins were identified in tubular cell exosomelike vesicles, including one (vitamin D binding protein) that had not been previously reported in exosome-like vesicles. Twelve were extracellular matrix proteins, including the basement membrane proteins type IV collagen, nidogen-1, agrin and fibulin-1. Urine from chronic kidney disease patients contained a higher amount of exosomal protein and exosomal OPG than urine from healthy volunteers. Specifically OPG was increased in autosomal dominant polycystic kidney disease urinary exosome-like vesicles and expressed by cystic epithelium in vivo. In conclusion, OPG is present in exosome-like vesicles secreted by proximal tubular epithelial cells and isolated from Chronic Kidney Disease urine.This work was supported by grants from the Instituto de Salud Carlos III (ISCIIIRETIC REDINREN RD06/0016, RD12/0021, PI11/01854, PI10/00072 PI09/ 00641 and PS09/00447); Comunidad de Madrid (Fibroteam S2010/BMD-2321, S2010/BMD-2378); Sociedad Española de NefrologÍa; European Network (HEALTH F2-2008-200647); DIALOK European project LSHB-CT-2007-036644; Fundacion Lilly and IRSIN/FRIAT to JE; Programa Intensificación Actividad Investigadora (ISCIII/ Agencia Laín-Entralgo/CM) to AO; Instituto de Salud Carlos III (FIS PI11/01401, CP09/00229); and Fundación Conchita Rábago de Jiménez DÍaz to GAL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip

At the Biological Modeling and Simulation Frontier

We provide a rationale for and describe examples of synthetic modeling and simulation (M&S) of biological systems. We explain how synthetic methods are distinct from familiar inductive methods. Synthetic M&S is a means to better understand the mechanisms that generate normal and disease-related phenomena observed in research, and how compounds of interest interact with them to alter phenomena. An objective is to build better, working hypotheses of plausible mechanisms. A synthetic model is an extant hypothesis: execution produces an observable mechanism and phenomena. Mobile objects representing compounds carry information enabling components to distinguish between them and react accordingly when different compounds are studied simultaneously. We argue that the familiar inductive approaches contribute to the general inefficiencies being experienced by pharmaceutical R&D, and that use of synthetic approaches accelerates and improves R&D decision-making and thus the drug development process. A reason is that synthetic models encourage and facilitate abductive scientific reasoning, a primary means of knowledge creation and creative cognition. When synthetic models are executed, we observe different aspects of knowledge in action from different perspectives. These models can be tuned to reflect differences in experimental conditions and individuals, making translational research more concrete while moving us closer to personalized medicine

Pharmacokinetics of oral etoposide in patients with hepatocellular carcinoma

Etoposide dosage in patients with liver dysfunction remains controversial. Since etoposide has a hepatic component to its clearance (CL) and shows a high degree of protein binding, hepatic impairment could affect etoposide disposition. However, the empiric recommendation that the dose of etoposide be decreased in such patients may reduce systemic exposure and be detrimental to its antitumor activity. To address these issues we studied the pharmacokinetics (PK) of etoposide in patients with hepatocellular carcinoma (HCC) and underlying cirrhosis (n = 17) treated with daily oral etoposide. Unbound etoposide was obtained by ultrafiltration. Etoposide concentrations (total and free drug) were measured by high-performance liquid chromatography (HPLC) and analyzed by noncompartmental equations. The patients had mild or moderate liver dysfunction. Albuminemia was in the normal range for all the patients. Creatininemia was normal in all but two patients. PK results (mean and range) showed that etoposide disposition was unchanged in patients with liver dysfunction. We found slightly high etoposide bioavailability [F, 61% (17-95%)] and clearance [CL, 1.1 (0.7-2.3) 1 h(-1) m(-2)] resulting in a normal degree of systemic exposure (AUC(oral) 27 mu g h ml(-1)). Normal protein binding [PB 93.2% (84.4-98.1%)] contributed to a normal level of exposure to free drug (AUC(f, oral) 1.9 mu g h ml(-1)). The distribution volume [V-ss 8.4 (6.1-13.2) l/m(2)] and the effective half-life [t(1/2eff), 5.1 (3.0-9.6) h] were normal. Median CL and protein binding did not differ in the seven patients with total bilirubin value of > 1.2 mg/dl as compared with the ten patients with total bilirubin levels of less than or equal to 1.2 mg/dl (1.3 versus 1.0 1 h(-1) m(-2) and 92.5% versus 93.4%, respectively). In agreement with this PK finding, we observed no clinical evidence of increased toxicity in patients with hyperbilirubinemia as compared with patients with normal bilirubinemia (mean WBC decrease 38% versus 47%). The only case of severe (grade 4) hematological toxicity was observed in one patient with reduced glomerular filtration. Since the pharmacological effects of etoposide correlate with the level of systemic exposure to the free drug, our data suggest that no dose reduction is needed in patients with HCC. It is even possible to increase the dose intensity in patients with favorable PK parameters under appropriate hematological and therapeutic drug monitoring