Identification of genome-wide targets of Olig2 in the adult mouse spinal cord using ChIP-Seq.

In jawed vertebrates, oligodendrocytes (OLs) are the myelin-producing glial cells responsible for ensheathment of axons within the central nervous system and are also crucial for remyelination following injury or disease. Olig2 is a crucial factor in the specification and differentiation of oligodendrocyte precursor cells (OPCs) that give rise to mature, myelin-producing OLs in the developing and postnatal CNS; however, its role in adulthood is less well understood. To investigate the role Olig2 plays in regulating gene expression in the adult OL lineage in a physiologically-relevant context, we performed chromatin immunoprecipitation followed by next generation sequencing analysis (ChIP-Seq) using whole spinal cord tissue harvested from adult mice. We found that many of the Olig2-bound sites were associated with genes with biological processes corresponding to OL differentiation (Nkx2.2, Nkx6.2, and Sip1), myelination and ensheathment (Mbp, Cldn11, and Mobp), as well as cell cycle and cytoskeletal regulation. This suggests Olig2 continues to play a critical role in processes related to OL differentiation and myelination well into adulthood.

Human Schwann cells exhibit long-term cell survival, are not tumorigenic and promote repair when transplanted into the contused spinal cord.

The transplantation of rodent Schwann cells (SCs) provides anatomical and functional restitution in a variety of spinal cord injury (SCI) models, supporting the recent translation of SCs to phase 1 clinical trials for human SCI. Whereas human (Hu)SCs have been examined experimentally in a complete SCI transection paradigm, to date the reported behavior of SCs when transplanted after a clinically relevant contusive SCI has been restricted to the use of rodent SCs. Here, in a xenotransplant, contusive SCI paradigm, the survival, biodistribution, proliferation and tumorgenicity as well as host responses to HuSCs, cultured according to a protocol analogous to that developed for clinical application, were investigated. HuSCs persisted within the contused nude rat spinal cord through 6 months after transplantation (longest time examined), exhibited low cell proliferation, displayed no evidence of tumorigenicity and showed a restricted biodistribution to the lesion. Neuropathological examination of the CNS revealed no adverse effects of HuSCs. Animals exhibiting higher numbers of surviving HuSCs within the lesion showed greater volumes of preserved white matter and host rat SC and astrocyte ingress as well as axon ingrowth and myelination. These results demonstrate the safety of HuSCs when employed in a clinically relevant experimental SCI paradigm. Further, signs of a potentially positive influence of HuSC transplants on host tissue pathology were observed. These findings show that HuSCs exhibit a favorable toxicity profile for up to 6 months after transplantation into the contused rat spinal cord, an important outcome for FDA consideration of their use in human clinical trials.

Proinflammatory cytokine regulation of cyclic AMP-phosphodiesterase 4 signaling in microglia in vitro and following CNS injury.

Cyclic AMP suppresses immune cell activation and inflammation. The positive feedback loop of proinflammatory cytokine production and immune activation implies that cytokines may not only be regulated by cyclic AMP but also conversely regulate cyclic AMP. This study examined the effects of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß on cyclic AMP-phosphodiesterase (PDE) signaling in microglia in vitro and after spinal cord injury (SCI) or traumatic brain injury (TBI). TNF-α or IL-1ß stimulation produced a profound reduction (>90%) of cyclic AMP within EOC2 microglia from 30 min that then recovered after IL-1ß but remained suppressed with TNF-α through 24 h. Cyclic AMP was also reduced in TNF-α-stimulated primary microglia, albeit to a lesser extent. Accompanying TNF-α-induced cyclic AMP reductions, but not IL-1ß, was increased cyclic AMP-PDE activity. The role of PDE4 activity in cyclic AMP reductions was confirmed by using Rolipram. Examination of pde4 mRNA revealed an immediate, persistent increase in pde4b with TNF-α; IL-1ß increased all pde4 mRNAs. Immunoblotting for PDE4 showed that both cytokines increased PDE4A1, but only TNF-α increased PDE4B2. Immunocytochemistry revealed PDE4B nuclear translocation with TNF-α but not IL-1ß. Acutely after SCI/TBI, where cyclic AMP levels are reduced, PDE4B was localized to activated OX-42(+) microglia; PDE4B was absent in OX-42(+) cells in uninjured spinal cord/cortex or inactive microglia. Immunoblotting showed PDE4B2 up-regulation from 24 h to 1 wk post-SCI, the peak of microglia activation. These studies show that TNF-α and IL-1ß differentially affect cyclic AMP-PDE signaling in microglia. Targeting PDE4B2 may be a putative therapeutic direction for reducing microglia activation in CNS injury and neurodegenerative diseases.

A selective phosphodiesterase-4 inhibitor reduces leukocyte infiltration, oxidative processes, and tissue damage after spinal cord injury.

We tested the hypothesis that a selective phosphodiesterase type 4 inhibitor (PDE4-I; IC486051) would attenuate early inflammatory and oxidative processes following spinal cord injury (SCI) when delivered during the first 3 days after injury. Rats receiving a moderately severe thoracic-clip-compression SCI were treated with the PDE4-I (0.5, 1.0, and 3.0 mg/kg IV) in bolus doses from 2-60 h post-injury. Doses at 0.5 mg/kg and 1.0 mg/kg significantly decreased myeloperoxidase (MPO) enzymatic activity (neutrophils), expression of a neutrophil-associated protein and of ED-1 (macrophages), and estimates of lipid peroxidation in cord lesion homogenates at 24 h and 72 h post-injury by 25-40%. The 3.0 mg/kg dose had small or no effects on these measures. The PDE4-I treatment (0.5 or 1.0 mg/kg) reduced expression of the oxidative enzymes gp91(phox), inducible nitric oxide synthase, and cyclooxygenase-2, and diminished free radical generation by up to 40%. Treatment with 0.5 mg/kg PDE4-I improved motor function (as assessed by the Basso-Beattie-Bresnahan scale) significantly from 4-8 weeks after SCI (average difference 1.3 points). Mechanical allodynia elicited from the hindpaw decreased by up to 25%. The PDE4-I treatment also increased white matter volume near the lesion at 8 weeks after SCI. In conclusion, the PDE4-I reduced key markers of oxidative stress and leukocyte infiltration, producing cellular protection, locomotor improvements, and a reduction in neuropathic pain. Early inhibition of PDE4 is neuroprotective after SCI when given acutely and briefly at sufficient doses.

Association of hyaluronic acid family members (HAS1, HAS2, and HYAL-1) with bladder cancer diagnosis and prognosis.

BACKGROUND: Cancer biomarkers are the backbone for the implementation of individualized approaches to bladder cancer (BCa). Hyaluronic acid (HA) and all 7 members of the HA family, that is, HA synthases (HA1, HA2, HA3), HYAL-1 hyaluronidase, and HA receptors (CD44s, CD44v, and RHAMM), function in tumor growth and progression. However, the diagnostic and prognostic potential of these 7 HA family members has not been compared simultaneously in any cancer. We evaluated the diagnostic and prognostic potential of HA family members in BCa. METHODS: Using quantitative PCR and immunohistochemistry, expression of HA family members was evaluated in prospectively collected bladder tissues (n = 72); mean and median follow-up were 29.6 ± 5.3 and 24 months, respectively. Transcript levels were also measured in exfoliated urothelial cells from urine specimens (n = 148). RESULTS: Among the HA family members, transcript levels of the HA synthases, HYAL-1, CD44v, and RHAMM were 4- to 16-fold higher in BCa tissues than in normal tissues (P < .0001); however, CD44s levels were lower. In univariate and multivariate analyses, tumor stage (P = .003), lymph node invasion (P = .033), HYAL-1 (P = .019), and HAS1 (P = .027) transcript levels, and HYAL-1 staining (P = .021) were independently associated with metastasis. Tumor stage (P = .019) and HYAL-1 (P = .046) transcript levels were also associated with disease-specific mortality. Although HA synthase and HYAL-1 transcript levels were elevated in exfoliated urothelial cells from BCa patients, the combined HAS2-HYAL-1 expression detected BCa with an overall sensitivity of 85.4% and a specificity of 79.5% and predicted BCa recurrence within 6 months (P = .004; RR = 6.7). CONCLUSIONS: HYAL-1 and HAS1 expression predicted BCa metastasis, and HYAL-1 expression also predicted disease-specific survival. Furthermore, the combined HAS2-HYAL-1 biomarker detected BCa and significantly predicted its recurrence.

HYAL-1 hyaluronidase: a potential prognostic indicator for progression to muscle invasion and recurrence in bladder cancer.

BACKGROUND: For bladder cancer (BCa) patients undergoing bladder-sparing treatments, molecular markers may aid in accurately predicting progression to muscle invasion and recurrence. Hyaluronic acid (HA) is a glycosaminoglycan that promotes tumor metastasis. Hyaluronoglucosaminidase 1 (HYAL-1)-type hyaluronidase (HAase) promotes tumor growth, invasion, and angiogenesis. Urinary HA and HAase levels are diagnostic markers for BCa. OBJECTIVE: We evaluated whether HA and HYAL-1 can predict progression to muscle invasion and recurrence among patients with non-muscle-invasive BCa. DESIGN, SETTING, AND PARTICIPANTS: : Based on tissue availability, tissue microarrays were prepared from a cohort of 178 BCa specimens (144 non-muscle invasive, 34 muscle invasive). Follow-up information was available on 111 patients with non-muscle-invasive BCa (mean follow-up: 69.5 mo); 58 patients recurred and 25 progressed to muscle invasion (mean time to progress: 22.3 mo). MEASUREMENTS: HA and HYAL-1 expression was evaluated by immunohistochemistry and graded for intensity and area of staining. Association of HA and HYAL-1 staining with BCa recurrence and muscle invasion was evaluated by univariate and multivariate models. RESULTS AND LIMITATIONS: HA and HYAL-1 expression correlated with tumor grade, stage, and multifocality (p<0.05). In non-muscle-invasive BCa specimens, HYAL-1 staining was higher (234.3+/-52.2; 200.6+/-61.4) if patients experienced progression to muscle invasion or recurrence when compared with no progression or recurrence (164.1+/-48.2; 172.1+/-57; p<0.001). HA staining correlated with muscle invasion (p<0.001). In univariate analysis, age (p=0.014), multifocality (p=0.023), and HYAL-1 staining (p<0.001) correlated with muscle invasion, whereas only HYAL-1 correlated with recurrence (p=0.013). In multivariate analysis, HYAL-1 significantly associated with muscle invasion (p<0.001; 76.8% accuracy) and recurrence (p=0.01; 67.8% accuracy). CONCLUSIONS: HYAL-1 is a potential prognostic marker for predicting progression to muscle invasion and recurrence.

Chronic spinal hemisection in rats induces a progressive decline in transmission in uninjured fibers to motoneurons.

Although most spinal cord injuries are anatomically incomplete, only limited functional recovery has been observed in people and rats with partial lesions. To address why surviving fibers cannot mediate more complete recovery, we evaluated the physiological and anatomical status of spared fibers after unilateral hemisection (HX) of thoracic spinal cord in adult rats. We made intracellular and extracellular recordings at L5 (below HX) in response to electrical stimulation of contralateral white matter above (T6) and below (L1) HX. Responses from T6 displayed reduced amplitude, increased latency and elevated stimulus threshold in the fibers across from HX, beginning 1-2 weeks after HX. Ultrastructural analysis revealed demyelination of intact axons contralateral to the HX, with a time course similar to the conduction changes. Behavioral studies indicated partial recovery which arrested when conduction deficits began. In conclusion, this study is the first demonstration of the delayed decline of transmission through surviving axons to individual lumbar motoneurons during chronic stage of incomplete spinal cord injury in adult rats. These findings suggest a chronic pathological state in intact fibers and necessity for prompt treatment to minimize it.

Hyaluronic acid synthase-1 expression regulates bladder cancer growth, invasion, and angiogenesis through CD44.

Hyaluronic acid (HA) promotes tumor metastasis and is an accurate diagnostic marker for bladder cancer. HA is synthesized by HA synthases HAS1, HAS2, or HAS3. We have previously shown that HAS1 expression in tumor tissues is a predictor of bladder cancer recurrence and treatment failure. In this study, we stably transfected HT1376 bladder cancer cells with HAS1-sense (HAS1-S), HAS1-antisense (HAS1-AS), or vector cDNA constructs. Whereas HAS1-S transfectants produced approximately 1.7-fold more HA than vector transfectants, HA production was reduced by approximately 70% in HAS1-AS transfectants. HAS1-AS transfectants grew 5-fold slower and were approximately 60% less invasive than vector and HAS1-S transfectants. HAS1-AS transfectants were blocked in G(2)-M phase of the cell cycle due to down-regulation of cyclin B1, cdc25c, and cyclin-dependent kinase 1 levels. These transfectants were also 5- to 10-fold more apoptotic due to the activation of the Fas-Fas ligand-mediated extrinsic pathway. HAS1-AS transfectants showed a approximately 4-fold decrease in ErbB2 phosphorylation and down-regulation of CD44 variant isoforms (CD44-v3, CD44-v6, and CD44-E) both at the protein and mRNA levels. However, no decrease in RHAMM levels was observed. The decrease in CD44-v mRNA levels was not due to increased mRNA degradation. Whereas CD44 small interfering RNA (siRNA) transfection decreased cell growth and induced apoptosis in HT1376 cells, HA addition modestly increased CD44 expression and cell growth in HAS1-AS transfectants, which could be blocked by CD44 siRNA. In xenograft studies, HAS1-AS tumors grew 3- to 5-fold slower and had approximately 4-fold lower microvessel density. These results show that HAS1 regulates bladder cancer growth and progression by modulating HA synthesis and HA receptor levels.

HAS1 expression in bladder cancer and its relation to urinary HA test.

Hyaluronic acid (HA) levels are elevated in bladder cancer tissues and regulate tumor growth and progression. Urinary HA levels measured by the HA test are an accurate marker for bladder cancer. In cells, HA is synthesized by one of the 3 HA-synthase(s) i.e., HAS1, HAS2 and HAS3. In this study, we examined HAS1 expression in bladder cancer cells and tissues. Real-time RT-PCR and northern blot analyses showed that HAS1 transcript levels are elevated 5- to 10-fold in bladder cancer tissues, when compared with normal tissues (p < 0.001). Among the 3 HAS1 splice variants, only HAS1-va was expressed in bladder tissues, but the expression was significantly lower than the wild type HAS1 transcript. Increased HAS1 expression in bladder tumor tissues correlated with increased tissue HA levels (p < 0.001). Size of the large HA species (2.0 x 10(6) D) present in bladder tissues was consistent with the size of the HA polymer synthesized by HAS1. The amount of HA produced by bladder cancer cell lines correlated with the expression of HAS1 protein. Immunohistochemical analyses of bladder tumor tissues showed that HAS1 and HA expression had 79-88% sensitivity and 83.3-100% specificity. Both HAS1 and HA expression in bladder cancer tissues correlated with a positive HA urine test (p < 0.001). HAS1 expression correlated with tumor recurrence, prior treatment (p < 0.05) and possibly disease progression (p = 0.058). Therefore, elevated HAS1 expression in bladder tumor tissues contributes to a positive HA urine test and may have some prognostic potential.

Uronate peaks and urinary hyaluronic acid levels correlate with interstitial cystitis severity.

PURPOSE: Levels of uronate, a basic component of urothelial glycosaminoglycans, are increased in urine specimens of patients with interstitial cystitis with severe symptoms. In this study we examined the urinary glycosaminoglycan profile and correlated the profile and urinary hyaluronic acid (a glycosaminoglycan) levels with symptom severity. MATERIALS AND METHODS: Urine specimens and completed O'Leary-Sant interstitial cystitis symptom and problem indexes questionnaires were obtained from 29 patients with interstitial cystitis, 14 normal individuals, and 14 patients with other benign pelvic and bladder conditions. Patients with interstitial cystitis were divided into group 1-1 or both indexes less than 50% maximum score, and group 2-both indexes 50% of maximum score or greater. All patients met the National Institutes of Diabetes and Digestive and Kidney Diseases criteria except regarding glomerulation. In a followup study 30 urine specimens were collected from 8 patients with interstitial cystitis and from 4 normal individuals during 12 months. The urinary glycosaminoglycan profile was determined by gel filtration chromatography. Glycosaminoglycan peaks were analyzed by polyacrylamide gel electrophoresis. Urinary hyaluronic acid levels were determined by the hyaluronic acid test. RESULTS: Group 2 urine specimens contained 3 uronate peaks, whereas urine specimens from normal individuals and patients in group 1 contained 1 or 2 peaks. Peak 1 consisted of macromolecular glycosaminoglycans whereas peaks 2 and 3 contained oligosaccharides. Urinary hyaluronic acid levels were 3 to 4-fold increased in group 2. Glycosaminoglycan profile and hyaluronic acid levels detected interstitial cystitis severity with 83% sensitivity, and 89.7% and 74.4% specificity, respectively. Interstitial cystitis urothelial cells/tissues also over expressed hyaluronic acid synthase 1 (which synthesizes hyaluronic acid) compared to normal urothelial cells/tissues. In the followup study urinary uronate levels, glycosaminoglycan profile and hyaluronic acid levels detected patients with severe symptoms with 73% sensitivity and 87% to 94% specificity. In both studies uronate, glycosaminoglycan profile and hyaluronic acid levels significantly correlated with interstitial cystitis severity (p <0.001). CONCLUSIONS: Urinary glycosaminoglycan profile, uronate content and hyaluronic acid levels are potentially useful markers for monitoring interstitial cystitis severity, and are likely to be involved in interstitial cystitis pathophysiology.