Mutations in Surfactant Protein C (SFTPC) can lead to fibrotic interstitial lung disease (ILD) with variable phenotypes, especially in children. The sources of phenotype variability are incompletely understood. A common MUC5B promoter variant rs35705950 is associated with adult Idiopathic Pulmonary Fibrosis (IPF). We examined whether MUC5B is similarly linked to ILD secondary to SFTPC mutations.
MUC5B concentration in bronchoalveolar lavage fluid (BALF) was measured in six pediatric patients with SFTPC mutations and diseased controls. Immunohistochemical localization of MUC5B was studied in fixed lung tissues in patients with SFTPC mutations, ABCA3 mutations, and controls. Genotyping for the MUC5B promoter variant rs35705950 was attempted in all samples.
MUC5B glycoprotein was increased in BALF of patients with SFTPC mutations compared to diseased controls (P = 0.04). MUC5B was unexpectedly present in cells morphologically consistent with alveolar epithelial type II cells in patients with SFTPC mutations in the BRICHOS domain. Genotyping for the MUC5B promoter variant was successful in 18/27 patients, and there was no significant relationship between the MUC5B promoter variant and the BALF or MUC5B localization.
MUC5B may play a role in the development of fibrosis in patients with SFTPC mutations, especially in patients with BRICHOS mutations. Understanding the role of MUC5B in adult and pediatric lung diseases may lead to a better understanding of the etiology of fibrotic lung disease as well as development of novel therapies.
surfactant; interstitial lung disease; mucins; pulmonary fibrosis; pediatrics; single nucleotide polymorphism; rare diseases; bronchoalveolar lavage
Idiopathic pulmonary fibrosis (IPF), a fatal disease that is a result of complex interactions between genetics and the environment, has limited treatment options. We have identified the MUC5B promoter polymorphism and other common genetic variants that in aggregate explain roughly one-third of disease risk. The MUC5B promoter polymorphism is the strongest and the most replicated genetic risk factor for IPF, appears to be protective and predictive in this disease, and is likely involved in disease pathogenesis through an increase in MUC5B expression in terminal bronchi and honeycombed cysts. Expression of MUC5B is also highly correlated with expression of cilium genes in IPF lung. Our work suggests that mucociliary dysfunction in the distal airway may play a role in the development of progressive fibroproliferative lung disease. In addition, our work has important implications for secondary prevention, early detection, and future early and personalized treatment based on genetic profiles.
MUC5B; mucociliary dysfunction; pulmonary fibrosis; genetic variant; gene expression profile
MenE is an o-succinylbenzoyl-CoA (OSB-CoA) synthetase in the bacterial menaquinone biosynthesis pathway and is a promising target for the development of novel antibacterial agents. The enzyme catalyzes CoA ligation via an acyl-adenylate intermediate, and we have previously reported tight-binding inhibitors of MenE based on stable acyl-sulfonyladenosine analogues of this intermediate, including OSB-AMS (1) which has an IC50 value of ≤ 25 nM for the Escherichia coli MenE. Herein, we show that OSB-AMS reduces menaquinone levels in S. aureus, consistent with its proposed mechanism of action, despite the observation that the antibacterial activity of OSB-AMS is ~1000-fold lower than the IC50 for enzyme inhibition. To inform the synthesis of MenE inhibitors with improved antibacterial activity, we have undertaken a structure–activity relationship (SAR) study stimulated by the knowledge that OSB-AMS can adopt two isomeric forms in which the OSB side chain exists either as an open-chain keto acid or a cyclic lactol. These studies revealed that negatively charged analogues of the keto-acid form bind, while neutral analogues do not, consistent with the hypothesis that the negatively-charged keto-acid form of OSB-AMS is the active isomer. X-ray crystallography and site-directed mutagenesis confirm the importance of a conserved arginine for binding the OSB carboxylate. Although most lactol isomers tested were inactive, a novel difluoroindanediol inhibitor (11) with improved antibacterial activity was discovered, providing a pathway toward the development of optimized MenE inhibitors in the future.
The androgen receptor (AR) is overexpressed and hyperactivated in human castration-resistant prostate cancer (CRPC). However, the determinants of AR overexpression in CRPC are poorly defined. Here we show that retinoid acid receptor-related orphan receptor γ (ROR-γ) is overexpressed and amplified in metastatic CRPC tumors, and that ROR-γ drives AR expression in the tumors. ROR-γ recruits coactivators SRC-1 and -3 to an AR-RORE to stimulate AR gene transcription. ROR-γ antagonists suppress the expression of AR and its variant AR-V7 in prostate cancer (PCa) cell lines and tumors. ROR-γ antagonists also markedly diminish genome-wide AR binding, H3K27ac abundance and expression of the AR gene network. Lastly, ROR-γ antagonists suppressed tumor growth in multiple AR-expressing but not AR-negative xenograft PCa models, and effectively sensitized CRPC tumors to enzalutamide, without overt toxicity in mice. Together, these results establish ROR-γ as a key player in CRPC by acting upstream of AR and a potential therapeutic target for advanced PCa.
Ligand-specific recruitment of arrestins facilitates functional selectivity of G-protein-coupled receptor signaling. Here, we describe agonist-selective recruitment of different arrestin isoforms to the delta opioid receptor in mice. A high-internalizing delta opioid receptor agonist (SNC80) preferentially recruited arrestin 2 and, in arrestin 2 knock-outs (KOs), we observed a significant increase in the potency of SNC80 to inhibit mechanical hyperalgesia and decreased acute tolerance. In contrast, the low-internalizing delta agonists (ARM390, JNJ20788560) preferentially recruited arrestin 3 with unaltered behavioral effects in arrestin 2 KOs. Surprisingly, arrestin 3 KO revealed an acute tolerance to these low-internalizing agonists, an effect never observed in wild-type animals. Furthermore, we examined delta opioid receptor–Ca2+ channel coupling in dorsal root ganglia desensitized by ARM390 and the rate of resensitization was correspondingly decreased in arrestin 3 KOs. Live-cell imaging in HEK293 cells revealed that delta opioid receptors are in pre-engaged complexes with arrestin 3 at the cell membrane and that ARM390 strengthens this membrane interaction. The disruption of these complexes in arrestin 3 KOs likely accounts for the altered responses to low-internalizing agonists. Together, our results show agonist-selective recruitment of arrestin isoforms and reveal a novel endogenous role of arrestin 3 as a facilitator of resensitization and an inhibitor of tolerance mechanisms.
SIGNIFICANCE STATEMENT Agonists that bind to the same receptor can produce highly distinct signaling events and arrestins are a major mediator of this ligand bias. Here, we demonstrate that delta opioid receptor agonists differentially recruit arrestin isoforms. We found that the high-internalizing agonist SNC80 preferentially recruits arrestin 2 and knock-out (KO) of this protein results in increased efficacy of SNC80. In contrast, low-internalizing agonists (ARM390 and JNJ20788560) preferentially recruit arrestin 3 and, surprisingly, KO of arrestin 3 produces acute tolerance and impaired receptor resensitization to these agonists. Arrestin 3 is in pre-engaged complexes with the delta opioid receptor at the cell membrane and low-internalizing agonists promote this interaction. This study reveals a novel role for arrestin 3 as a facilitator of receptor resensitization.
arrestin; DRG; GPCR; pain; resensitization; tolerance
The impact of cardiopulmonary bypass (CPB) usage in level III-IV tumor thrombectomy on surgical and oncologic outcomes is unknown. We sought to determine the impact of cardiopulmonary bypass (CPB) on overall and cancer specific survival, as well as surgical complication rates, and immediate outcomes in patients undergoing nephrectomy and level III-IV tumor thrombectomy with or without CPB.
Patients and Methods
We retrospectively analyzed 362 patients with RCC and with level III or IV tumor thrombus from 1992 to 2012 in 22 US and European centers. Cox proportional hazards models were used to compare overall and cancer-specific survival between patients with and without CPB. Perioperative mortality and complications rates were assessed using logistic regression analyses.
The median overall survival was 24.6 months in non-CPB patients and 26.6 months in CPB patients. Overall survival and cancer-specific survival (CSS) did not differ significantly in both groups, neither in univariate analysis nor when adjusting for known risk factors. In multivariate analysis, no significant differences were seen in hospital LOS, Clavien 1-4 complication rate, intraoperative or 30 day mortality, and CSS between both groups. Limitations include the retrospective nature of the study.
In our multi-institutional analysis, the use of cardiopulmonary bypass did not significantly impact cancer specific survival or overall survival in patients undergoing nephrectomy and level III or IV tumor thrombectomy. Neither approach was independently associated with increased mortality in the multivariate analysis. Higher surgical complications were not independently associated with the use of CPB.
renal cell carcinoma; cardiopulmonary by-pass; vena cava tumor thrombus; survival; surgical complication
It is known that over expression of IL6 in prostate cancer cells confer enzalutamide resistance and that this may occur through constitutive Stat3 activation. Additionally, recent pre-clinical studies suggested enzalutamide might have the potential adverse effect of inducing metastasis of prostate cancer cells via Stat3 activation. This study is aimed to target Stat3 activation and improve enzalutamide therapy.
Sensitivity of prostate cancer cells to enzalutamide was tested using cell growth assays and clonogenic assays. Wound healing and invasion assays were performed to determine cell migration and invasion in vitro. Quantitative reverse transcription-PCR, ELISAand Western blotting were performed to detect expression levels of PSA, c-Myc, survivin, Stat3 and AR. ChIP assay was performed to examine recruitment of AR to the PSA promoter.
In the present study, we found niclosamide, a previously identified novel inhibitor of androgen receptor variant (AR-V7), inhibited Stat3 phosphorylation and expression of downstream target genes. Niclosamide synergistically reversed enzalutamide resistance in prostate cancer cells and combination treatment of niclosamide with enzalutamide significantly induced cell apoptosis and inhibited cell growth, colony formation, cell migration and invasion. Knock down of Stat3 abrogated enzalutamide resistance resulting in reduced recruitment of AR to the PSA promoter in prostate cancer cells expressing IL6. Moreover, niclosamide reversed enzalutamide resistance by down-regulating Stat3 target gene expression Stat3and abrogating recruitment of AR to PSA promoter resulting in PSA inhibition.
This study demonstrated the IL6-Stat3-AR axis in prostate cancer is one of the crucial mechanisms of enzalutamide resistance. Niclosamide has the potential to target the IL6-Stat3-AR pathway to overcome enzalutamide resistance and inhibit migration and invasion in advanced prostate cancer.
prostate cancer; Stat3; interleukin-6; niclosamide; enzalutamide
Castration resistant prostate cancer (CRPC) remains dependent on androgen receptor (AR) signaling. Alternative splicing of the AR to generate constitutively active, ligand-independent variants is one of the principal mechanisms that promote the development of resistance to next-generation anti-androgens such as enzalutamide. Here, we demonstrate that the splicing factor heterogeneous nuclear RNA-binding protein A1 (hnRNPA1) plays a pivotal role in the generation of AR splice variants such as AR-V7. HnRNPA1 is overexpressed in prostate tumors compared to benign prostates and its expression is regulated by NF-kappaB2/p52 and c-Myc. CRPC cells resistant to enzalutamide exhibit higher levels of NF-kappaB2/p52, c-Myc, hnRNPA1, and AR-V7. Levels of hnRNPA1 and of AR-V7 are positively correlated with each other in PCa. The regulatory circuit involving NF-kappaB2/p52, c-Myc and hnRNPA1 plays a central role in the generation of AR splice variants. Downregulation of hnRNPA1 and consequently of AR-V7 resensitizes enzalutamide-resistant cells to enzalutamide, indicating that enhanced expression of hnRNPA1 may confer resistance to AR-targeted therapies by promoting the generation of splice variants. These findings may provide a rationale for co-targeting these pathways to achieve better efficacy through AR blockade.
hnRNPA1; AR-V7; c-Myc; Enzalutamide; Androgen Receptor
Thiocyanate (SCN) is used by the innate immune system, but less is known about its impact on inflammation and oxidative stress. Granulocytes oxidize SCN to evolve the bactericidal hypothiocyanous acid, which we previously demonstrated is metabolized by mammalian, but not bacterial, thioredoxin reductase (TrxR). There is also evidence that SCN is dysregulated in cystic fibrosis (CF), a disease marked by chronic infection and airway inflammation. To investigate antiinflammatory effects of SCN, we administered nebulized SCN or saline to β epithelial sodium channel (βENaC) mice, a phenotypic CF model. SCN significantly decreased airway neutrophil infiltrate and restored the redox ratio of glutathione in lung tissue and airway epithelial lining fluid to levels comparable to wild type. Furthermore, in Pseudomonas aeruginosa–infected βENaC and wild-type mice, SCN decreased inflammation, proinflammatory cytokines, and bacterial load. SCN also decreased airway neutrophil chemokine keratinocyte chemoattractant (also known as C-X-C motif chemokine ligand 1) and glutathione sulfonamide, a biomarker of granulocyte oxidative activity, in uninfected βENaC mice. Lung tissue TrxR activity and expression increased in inflamed lung tissue, providing in vivo evidence for the link between hypothiocyanous acid metabolism by TrxR and the promotion of selective biocide of pathogens. SCN treatment both suppressed inflammation and improved host defense, suggesting that nebulized SCN may have important therapeutic utility in diseases of both chronic airway inflammation and persistent bacterial infection, such as CF.
hypothiocyanous acid; innate immunity; antioxidant; glutathione sulfonamide; nebulization
Continuous passive motion manifests therapeutic effects on inflamed articular joints by an as-yet-unknown mechanism. Here, we show that application of cyclic tensile stress (CTS) in vitro abrogates the catabolic effects of IL-1β on chondrocytes. The effects of CTS are mediated by down-regulation of IL-1β-dependent inducible NO production, and are directly attributed to the inhibition of inducible NO synthase (iNOS) mRNA expression and protein synthesis. The inhibition of iNOS induction by CTS is paralleled by abrogation of IL-1β-induced down-regulation of proteoglycan synthesis. Furthermore, CTS inhibits iNOS expression and up-regulates proteoglycan synthesis at concentrations of IL-1β frequently observed in inflamed arthritic joints, suggesting that the actions of CTS may be clinically relevant in suppressing the sustained effects of pathological levels of IL-1β in vivo. These results are the first to demonstrate that mechanisms of the intracellular actions of CTS in IL-1β-activated chondrocytes are mediated through inhibition of a key molecule in the signal transduction pathway that leads to iNOS expression.
Inflammatory cytokines play a major role in cartilage destruction in diseases such as osteoarthritis and rheumatoid arthritis. Because physical therapies such as continuous passive motion yield beneficial effects on inflamed joints, we examined the intracellular mechanisms of mechanical strain-mediated actions in chondrocytes. By simulating the effects of continuous passive motion with cyclic tensile strain (CTS) on chondrocytes in vitro, we show that CTS is a potent antagonist of IL-1β actions and acts as both an anti-inflammatory and a reparative signal. Low magnitude CTS suppresses IL-1β-induced mRNA expression of multiple proteins involved in catabolic responses, such as inducible NO synthase, cyclo-oxygenase II, and collagenase. CTS also counteracts cartilage degradation by augmenting mRNA expression for tissue inhibitor of metalloproteases and collagen type II that are inhibited by IL-1β. Additionally, CTS augments the reparative process via hyperinduction of aggrecan mRNA expression and abrogation of IL-1β-induced suppression of proteoglycan synthesis. Nonetheless, the presence of an inflammatory signal is a prerequisite for the observed CTS actions, as exposure of chondrocytes to CTS alone has little effect on these parameters. Functional analysis suggests that CTS-mediated anti-inflammatory actions are not mediated by IL-1R down-regulation. Moreover, as an effective antagonist of IL-1β, the actions of CTS may involve disruption/regulation of signal transduction cascade of IL-1β upstream of mRNA transcription. These observations are the first to show that CTS directly acts as an anti-inflammatory signal on chondrocytes and provide a molecular basis for its actions.
Accurate translation of the genetic information from DNA to protein is maintained by multiple quality control steps from bacteria to mammals. Genetic and environmental alterations have been shown to compromise translational quality control and reduce fidelity during protein synthesis. The physiological impact of increased translational errors is not fully understood. While generally considered harmful, translational errors have recently been shown to benefit cells under certain stress conditions. In this work, we describe a novel regulatory pathway in which reduced translational fidelity downregulates expression of flagellar genes and suppresses bacterial motility. Electron microscopy imaging shows that the error-prone Escherichia coli strain lacks mature flagella. Further genetic analyses reveal that translational errors upregulate expression of a small RNA DsrA through enhancing its transcription, and deleting DsrA from the error-prone strain restores motility. DsrA regulates expression of H-NS and RpoS, both of which regulate flagellar genes. We demonstrate that an increased level of DsrA in the error-prone strain suppresses motility through the H-NS pathway. Our work suggests that bacteria are capable of switching on and off the flagellar system by altering translational fidelity, which may serve as a previously unknown mechanism to improve fitness in response to environmental cues.
The mechanisms by which chondrocytes convert biomechanical signals into intracellular biochemical events are not well understood. In this study, we sought to determine the intracellular mechanisms of the magnitude-dependent actions of mechanical signals.
Chondrocytes isolated from rabbit articular cartilage were grown on flexible membranes. Cells were subjected to cyclic tensile strain (CTS) of various magnitudes in the presence or absence of interleukin-1β (IL-1β), which was used as a proinflammatory signal for designated time intervals. The regulation of NF-κB was measured by reverse transcriptase–polymerase chain reaction, electrophoretic mobility shift assay, and immunofluorescence.
CTS of low magnitudes (4–8% equibiaxial strain) was a potent inhibitor of IL-1β–dependent NF-κB nuclear translocation. Cytoplasmic retention of NF-κB and reduction of its synthesis led to sustained suppression of proinflammatory gene induction. In contrast, proinflammatory signals generated by CTS of high magnitudes (15–18% equibiaxial strain) mimicked the actions of IL-1β and induced rapid nuclear translocation of NF-κB subunits p65 and p50.
Magnitude-dependent signals of mechanical strain utilize the NF-κB transcription factors as common elements to abrogate or aggravate proinflammatory responses. Furthermore, the intracellular events induced by mechanical overload are similar to those that are initiated by proinflammatory cytokines in arthritis.
Opioid drugs are potent modulators of many physiological and psychological processes. When given acutely, they can elicit the signature responses of euphoria and analgesia that societies have coveted for centuries. Repeated, or chronic, use of opioids induces adaptive or allostatic changes that modify neuronal circuitry and create an altered normality — the “drug-dependent” state. This state, at least that exhibited by those maintained continuously on long-acting opioid drugs such as methadone or buprenorphine, is generally indistinguishable from the drug-naïve state for most overt behaviors. The consequences of the allostatic changes (cellular, circuit, and system adaptations) that accompany the drug-dependent state are revealed during drug withdrawal. Drug cessation triggers a temporally orchestrated allostatic re-establishment of neuronal systems, which is manifested as opposing physiological and psychological effects to those exhibited by acute drug intoxication. Some withdrawal symptoms, such as physical symptoms (sweating, shaking, and diarrhea) resolve within days, whilst others, such as dysphoria, insomnia, and anxiety, can linger for months, and some adaptations, such as learned associations, may be established for life. We will briefly discuss the cellular mechanisms and neural circuitry that contribute to the opioid drug-dependent state, inferring an emerging role for neuroinflammation. We will argue that opioid addictive behaviors result from a learned relationship between opioids and relief from an existing or withdrawal-induced anxiogenic and/or dysphoric state. Furthermore, a future stressful life event can recall the memory that opioid drugs alleviate negative affect (despair, sadness, and anxiety) and thereby precipitate craving, resulting in relapse. A learned association of relief of aversive states would fuel drug craving in vulnerable people living in an increasingly stressful society. We suggest that this route to addiction is contributive to the current opioid epidemic in the USA.
Learned Associative Model; pass-forward allostasis; withdrawal relief; aversive states; opioid epidemic
It is thought that frontostriatal circuits play an important role in mediating conditioned behavioral responses to environmental stimuli that were previously encountered during drug administration. However, the neural correlates of conditioned responses to drug-associated cues are not well understood at the level of large populations of simultaneously recorded neurons, or at the level of local field potential (LFP) synchrony in the frontostriatal network.
It is thought that frontostriatal circuits play an important role in mediating conditioned behavioral responses to environmental stimuli that were previously encountered during drug administration. However, the neural correlates of conditioned responses to drug-associated cues are not well understood at the level of large populations of simultaneously recorded neurons, or at the level of local field potential (LFP) synchrony in the frontostriatal network. Here we introduce a behavioral assay of conditioned arousal to cocaine cues involving pupillometry in awake head-restrained mice. After just 24 h of drug abstinence, brief exposures to olfactory stimuli previously paired with cocaine injections led to a transient dilation of the pupil, which was greater than the dilation effect to neutral cues. In contrast, there was no cue-selective change in locomotion, as measured by the rotation of a circular treadmill. The behavioral assay was combined with simultaneous recordings from dozens of electrophysiologically identified units in the medial prefrontal cortex (mPFC) and ventral striatum (VS). We found significant relationships between cocaine cue-evoked pupil dilation and the proportion of inhibited principal cells in the mPFC and VS. Additionally, LFP coherence analysis revealed a significant correlation between pupillary response and synchrony in the 25–45 Hz frequency band. Together, these results show that pupil dilation is sensitive to drug-associated cues during acute stages of abstinence, and that individual animal differences in this behavioral arousal response can be explained by two complementary measures of frontostriatal network activity.
cocaine; conditioned arousal; large-scale recordings; prefrontal cortex; pupillometry; striatum
The incidence of urothelial carcinoma of the urinary bladder (bladder cancer) remains high. While other solid organ malignancies have seen significant improvement in morbidity and mortality, there has been little change in bladder cancer mortality in the past few decades. The mortality is mainly driven by muscle invasive bladder cancer, but the cancer burden remains high even in nonmuscle invasive bladder cancer due to high recurrence rates and risk of progression. While apoptosis deregulation has long been an established pathway for cancer progression, nonapoptotic pathways have gained prominence of late. Recent research in the role of autophagy in other malignancies, including its role in treatment resistance, has led to greater interest in the role of autophagy in bladder cancer. Herein, we summarize the literature regarding the role of autophagy in bladder cancer progression and treatment resistance. We address it by systematically reviewing treatment modalities for nonmuscle invasive and muscle invasive bladder cancer.
Autophagy; Drug resistance; Urinary bladder neoplasms
Siglec-F is a glycan binding protein selectively expressed on mouse eosinophils. Its engagement induces apoptosis, suggesting a pathway for ameliorating eosinophilia in asthma and other eosinophil-associated diseases. Siglec-F recognizes sialylated, sulfated glycans in glycan binding assays, but the identities of endogenous sialoside ligands and their glycoprotein carriers in vivo are unknown.
Lungs from normal and mucin-deficient mice, as well as mouse tracheal epithelial cells from mice, were interrogated in vitro and in vivo for the expression of Siglec-F ligands. Western blotting and immunocytochemistry used Siglec-F-Fc as a probe for directed purification, followed by liquid chromatography-tandem mass spectrometric analysis of recognized glycoproteins. Purified components were tested in mouse eosinophil binding assays and flow cytometry-based cell death assays.
We detected mouse lung glycoproteins that bound to Siglec-F; binding was sialic-acid dependent. Proteomic analysis of Siglec-F binding material identified Muc5b and Muc4. Cross-affinity enrichment and histochemical analysis of lungs from mucin-deficient mice assigned and validated the identity of Muc5b as one glycoprotein ligand for Siglec-F. Purified mucin preparations carried sialylated and sulfated glycans, bound to eosinophils and induced their death in vitro. Mice conditionally deficient in Muc5b displayed exaggerated eosinophilic inflammation in response to intratracheal installation of IL-13.
These data identify a previously unrecognized endogenous anti-inflammatory property of airway mucins by which their glycans can control lung eosinophilia through engagement of Siglec-F.
Eosinophil; asthma; Siglec-F; mucin; Muc5b; Muc4; apoptosis; glycan ligands; epithelium; glands; lung; airway
Gold and gold alloys, in the form of supported nanoparticles, have been shown over the last three decades to be highly effective oxidation catalysts. Mixed metal oxide perovskites, with their high structural tolerance, are ideal for investigating how changes in the chemical composition of supports affect the catalysts' properties, while retaining similar surface areas, morphologies and metal co-ordinations. However, a significant disadvantage of using perovskites as supports is their high crystallinity and small surface area. We report the use of a supercritical carbon dioxide anti-solvent precipitation methodology to prepare large surface area lanthanum based perovskites, making the deposition of 1 wt% AuPt nanoparticles feasible. These catalysts were used for the selective oxidation of glycerol. By changing the elemental composition of the perovskite B site, we dramatically altered the reaction pathway between a sequential oxidation route to glyceric or tartronic acid and a dehydration reaction pathway to lactic acid. Selectivity profiles were correlated to reported oxygen adsorption capacities of the perovskite supports and also to changes in the AuPt nanoparticle morphologies. Extended time on line analysis using the best oxidation catalyst (AuPt/LaMnO3) produced an exceptionally high tartronic acid yield. LaMnO3 produced from alternative preparation methods was found to have lower activities, but gave comparable selectivity profiles to that produced using the supercritical carbon dioxide anti-solvent precipitation methodology.
Tendon injuries are common and present a clinical challenge to orthopedic surgery mainly because these injuries often respond poorly to treatment and require prolonged rehabilitation. Therapeutic options used to repair ruptured tendons have consisted of suture, autografts, allografts, and synthetic prostheses. To date, none of these alternatives has provided a successful long-term solution, and often the restored tendons do not recover their complete strength and functionality. Unfortunately, our understanding of tendon biology lags far behind that of other musculoskeletal tissues, thus impeding the development of new treatment options for tendon conditions. Hence, in this review, after introducing the clinical significance of tendon diseases and the present understanding of tendon biology, we describe and critically assess the current strategies for enhancing tendon repair by biological means. These consist mainly of applying growth factors, stem cells, natural biomaterials and genes, alone or in combination, to the site of tendon damage. A deeper understanding of how tendon tissue and cells operate, combined with practical applications of modern molecular and cellular tools could provide the long awaited breakthrough in designing effective tendon-specific therapeutics and overall improvement of tendon disease management.
Tendon; Tendon repair; Growth Factors; Cell-based therapy; Mesenchymal stem cells; Embryonic stem cells; Tendon-derived cells; Natural biomaterials; Gene therapy
The introduction of enzalutamide and abiraterone has led to improvement in the treatment of metastatic castration-resistant prostate cancer (mCRPC). However, acquired resistance to enzalutamide and abiraterone therapies frequently develops within a short period in many patients. In the present study, we developed enzalutamide resistant prostate cancer cells in an effort to understand the mechanisms of resistance. Global gene expression analysis showed that steroid biosynthesis pathway is activated in enzalutamide resistant prostate cancer cells. One of the crucial steroidogenic enzymes, AKR1C3, was significantly elevated in enzalutamide resistant cells. In addition, AKR1C3 is highly expressed in metastatic and recurrent prostate cancer and in enzalutamide resistant prostate xenograft tumors. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis of the steroid metabolites revealed that androgen precursors such as cholesterol, DHEA and progesterone, as well as androgens are highly up regulated in enzalutamide resistant prostate cancer cells compared to the parental cells. Knock down of AKR1C3 expression by shRNA or inhibition of AKR1C3 enzymatic activity by indomethacin resensitized enzalutamide resistant prostate cancer cells to enzalutamide treatment both in vitro and in vivo. In contrast, overexpression of AKR1C3 confers resistance to enzalutamide. Furthermore, the combination of indomethacin and enzalutamide resulted in significant inhibition of enzalutamide-resistant tumor growth. These results suggest that AKR1C3 activation is a critical resistance mechanism associated with enzalutamide resistance, targeting intracrine androgens and AKR1C3 will overcome enzalutamide resistance and improve survival of advanced prostate cancer patients.
prostate cancer; enzalutamide; intracrine androgens; AKR1C3; indomethacin
HIV/hepatitis C virus (HCV) patients have a 3-fold increased fracture incidence compared to uninfected patients. The impact of HCV therapy on bone health is unclear. We evaluated bone turnover markers (BTM) in well-controlled (HIV RNA <50 copies/ml) HIV/HCV-coinfected patients who received pegylated interferon-α and ribavirin (PEG-IFN/RBV) in ACTG trial A5178. Early virologic responders (EVR: ≥2 log HCV RNA drop at week 12) continued PEG-IFN/RBV and non-EVRs were randomized to continuation of PEG-IFN alone or observation. We assessed changes in C-terminal telopeptide of type 1 collagen (CTX; bone resorption marker) and procollagen type I intact N-terminal propeptide (P1NP; bone formation marker), and whether BTM changes were associated with EVR, complete early virologic response (cEVR: HCV RNA <600 IU/ml at week 12), or PEG-IFN treatment. A total of 192 subjects were included. After 12 weeks of PEG-IFN/RBV, CTX and P1NP decreased: −120 pg/ml and −8.48 μg/liter, respectively (both p < 0.0001). CTX declines were greater in cEVR (N = 91; vs. non-cEVR (N = 101; p = 0.003). From week 12 to 24, CTX declines were sustained among EVR patients who continued PEG-IFN/RBV (p = 0.027 vs. non-EVR) and among non-EVR patients who continued PEG-IFN alone (p = 0.022 vs. Observation). Median decreases of P1NP in EVR vs. non-EVR were similar at weeks 12 and 24. PEG-IFN-based therapy for chronic HCV markedly reduces bone turnover. It is unclear whether this is a direct IFN effect or a result of HCV viral clearance, or whether they will result in improved bone mineral density. Further studies with IFN-free regimens should explore these questions.
Injuries to the musculoskeletal system are common, debilitating and expensive. In many cases, healing is imperfect, which leads to chronic impairment. Gene transfer might improve repair and regeneration at sites of injury by enabling the local, sustained and potentially regulated expression of therapeutic gene products; such products include morphogens, growth factors and anti-inflammatory proteins. Proteins produced endogenously as a result of gene transfer are nascent molecules that have undergone post-translational modification. In addition, gene transfer offers particular advantages for the delivery of products with an intracellular site of action, such as transcription factors and noncoding RNAs, and proteins that need to be inserted into a cell compartment, such as a membrane. Transgenes can be delivered by viral or nonviral vectors via in vivo or ex vivo protocols using progenitor or differentiated cells. The first gene transfer clinical trials for osteoarthritis and cartilage repair have already been completed. Various bone-healing protocols are at an advanced stage of development, including studies with large animals, and human trials are envisaged. Other applications in the repair and regeneration of skeletal muscle, intervertebral disc, meniscus, ligament and tendon are in preclinical development. In addition to scientific, medical and safety considerations, clinical translation is constrained by social, financial and logistical issues.
Ecological and biogeochemical processes in lakes are strongly dependent upon water temperature. Long-term surface warming of many lakes is unequivocal, but little is known about the comparative magnitude of temperature variation at diel timescales, due to a lack of appropriately resolved data. Here we quantify the pattern and magnitude of diel temperature variability of surface waters using high-frequency data from 100 lakes. We show that the near-surface diel temperature range can be substantial in summer relative to long-term change and, for lakes smaller than 3 km2, increases sharply and predictably with decreasing lake area. Most small lakes included in this study experience average summer diel ranges in their near-surface temperatures of between 4 and 7°C. Large diel temperature fluctuations in the majority of lakes undoubtedly influence their structure, function and role in biogeochemical cycles, but the full implications remain largely unexplored.
Opioid dependence is accompanied by neuroplastic changes in reward circuitry leading to a negative affective state contributing to addictive behaviors and risk of relapse. The current study presents a neuroimmune mechanism through which chronic opioids disrupt the ventral tegmental area (VTA) dopaminergic circuitry that contributes to impaired reward behavior. Opioid dependence was induced in rodents by treatment with escalating doses of morphine. Microglial activation was observed in the VTA following spontaneous withdrawal from chronic morphine treatment. Opioid-induced microglial activation resulted in an increase in brain-derived neurotrophic factor (BDNF) expression and a reduction in the expression and function of the K+Cl− co-transporter KCC2 within VTA GABAergic neurons. Inhibition of microglial activation or interfering with BDNF signaling prevented the loss of Cl− extrusion capacity and restored the rewarding effects of cocaine in opioid-dependent animals. Consistent with a microglial-derived BDNF-induced disruption of reward, intra-VTA injection of BDNF or a KCC2 inhibitor resulted in a loss of cocaine-induced place preference in opioid-naïve animals. The loss of the extracellular Cl− gradient undermines GABAA-mediated inhibition, and represents a mechanism by which chronic opioid treatments can result in blunted reward circuitry. This study directly implicates microglial-derived BDNF as a negative regulator of reward in opioid-dependent states, identifying new therapeutic targets for opiate addictive behaviors.
Much effort is expended in developing biomimetic scaffolds that provide the micro-architecture of native tissue with appropriate cellular niches. Such scaffolds are often seeded with progenitor cells to generate engineered replacements for diseased or damaged tissues. An alternative approach relies on biology, rather than technology, to provide scaffolds containing progenitor cells in authentic niches. This article describes the use of accessible living tissues containing endogenous progenitor cells in their native, physiological environments. Such tissues also possess scaffolding properties, and can be readily harvested, manipulated and returned to the patient intra-operatively to facilitate repair and regeneration. Our group has explored the in situ genetic manipulation of cells within these tissues before they are reimplanted, although other means of modulation are certainly possible. Examples of suitable donor tissues include marrow, skeletal muscle and fat. In the case of marrow, clotting produces a moldable, autologous fibrin matrix containing endogenous cells; if necessary, exogenous cells can be added prior to clotting. These approaches have been studied experimentally in orthopaedic contexts, particularly for the healing and regeneration of bone and cartilage.