This study examined the associations between acculturation and orofacial pain and healthcare among Hispanic adults. Understanding the effects of acculturation on Hispanic oral health may improve understanding of oral health disparities in the United States. Data were collected from 911 Hispanic adults reporting tooth pain and painful oral sores who were part of a larger study of South Florida residents conducted using random-digit dialing methodology. The survey was conducted in Spanish or English by bilingual interviewers per the choice of each respondent. Greater use of the Spanish language was associated with disparities in healthcare visits for orofacial pain, not having a usual dentist, having greater pain, increased difficulty eating and sleeping, and more depression. Respondents’ and their parents’ nativity (families that had been in the United States longer) and those identifying more closely to Hispanic culture were also predictive of several of the outcomes. Gender, financial status, and age, independent of acculturation, were also associated with orofacial pain, accessing health care, and pain-related loss of functioning among Hispanics. The data support the hypothesis that Hispanics with less acculturation are less able to access needed oral health care. This study highlights the need for outreach programs targeting recent Hispanic immigrants focusing on oral health care.
Disparities; orofacial pain; dental pain; Hispanic; acculturation; depression; health care use; sleep disturbance
Minimal change disease (MCD), the most common idiopathic nephrotic syndrome in children, is characterized by proteinuria and loss of glomerular visceral epithelial cell (podocyte) ultrastructure. Lipopolysaccharide (LPS) and puromycin aminonucleoside (PAN) are used to study podocyte injury in models of MCD in vivo and in vitro. We hypothesized that LPS and PAN influence components of the innate immune system in podocytes such as the Toll-Like Receptor (TLRs), TLR adapter molecules, and associated cytokines. Our results show that cultured human podocytes constitutively express TLRs 1–6 and TLR-10, but not TLRs 7–9. LPS (25 μg/ml) or PAN (60 μg/ml) caused comparable derangement of the actin cytoskeleton in podocytes. Quantitative RT-PCR analysis show that LPS differentially up-regulated the expression of genes for TLRs (1 > 4 ≥ 2 > 3 > 6 > 5), the adapter molecule, MyD88, and transcription factor NF-κB within one hour. LPS also caused increased levels of IL-6, IL-8 and MCP1 without exerting any effect on TNF-α, IFN-α or TGF-β1 at 24 h. Immunofluorescence intensity analysis of confocal microscopy images showed that LPS induced a significant increase in nuclear translocation of NF-κB by 6 h. In contrast, PAN-induced only small changes in the expression of TLRs 2–6 that included a persistent increase in TLRs 2 and 5, a transient increase in TLR-4, and a gradual increase in TLRs 3 and 6 between 1 and 6 h. Correspondingly, it did not alter pro-inflammatory cytokine levels in podocytes. However, PAN induced a low but significant increase in NF-κB nuclear translocation within one hour that remained unchanged up to 6 h. In summary, these novel findings show that LPS, a known TLR-4 ligand, induced the gene expression of multiple TLRs with maximum effect on the expression of TLR-1 suggesting a loss of receptor selectivity and induction of receptor interactions in podocytes. A comparable derangement of the podocyte cytoskeleton and significant increase in the nuclear translocation of NF-κB by PAN suggest that disparate but complementary mechanisms may contribute to the development of podocytopathy in MCD.
Innate immunity; Toll-like receptors; Cytokines; Lipopolysaccharide; Puromycin Aminonucleoside; Minimal Change Disease; Glomerular filtration barrier; Podocytes
Drug discovery and development efforts critically rely on cell-based assays for high-throughput screening. These assay systems mostly utilize immortalized cell lines, such as human embryonic kidney cells, and can provide information on cytotoxicity and cell viability, permeability and uptake of compounds as well as receptor pharmacology. While this approach has proven extremely useful for single-target pharmacology, there is an urgent need for neuropharmacological studies to screen novel drug candidates in a cellular environment resembles neurons in vivo more closely, in order to gain insight into the involvement of multiple signaling pathways. Primary cultured neuronal cells, such as cortical neurons, have long been used for basic research and low-throughput screening and assay development, and may thus be suitable candidates for the development of neuropharmacological high-throughput screening approaches. We here developed and optimized protocols for the use of primary cortical neuronal cells in high-throughput assays for neuropharmacology and neuroprotection, including calcium mobilization, cytotoxicity and viability as well as ion channel pharmacology. Our data show low inter-experimental variability and similar reproducibility as conventional cell line assays. We conclude that primary neuronal cultures provide a viable alternative to cell lines in high-throughput assay systems by providing a cellular environment more closely resembling physiological conditions in the central nervous system.
Primary neuronal culture; Cytotoxicity; Calcium mobilization; Drug screening; Neuroprotection; High-throughput screening
Cyclodextrins are sugar compounds that are increasingly finding medicinal uses due to their ability to complex with hydrophobic molecules. One cyclodextrin in particular, 2-hydroxypropyl-β-cyclodextrin (HPβCD), is used as a carrier to solubilize lipophilic drugs and is itself being considered as a therapeutic agent for treatment of Niemann-Pick Type C disease, due to its ability to mobilize cholesterol. Results from toxicological studies suggest that HPβCD is generally safe, but a recent study has found that it causes hearing loss in cats. Whether the hearing loss occurred via death of cochlear hair cells, rendering it permanent, was unexplored. In the present study, we examined peripheral auditory function and cochlear histology in mice after subcutaneous injection of HPβCD to test for hearing loss and correlate any observed auditory deficits with histological findings. On average, auditory brainstem response thresholds were elevated at 4, 16, and 32 kHz in mice one week after treatment with 8,000 mg/kg. In severely affected mice all outer hair cells were missing in the basal half of the cochlea. In many cases, surviving hair cells in the cochlear apex exhibited abnormal punctate distribution of the motor protein prestin, suggesting long term changes to membrane composition and integrity. Mice given a lower dose of 4,000 mg/kg exhibited hearing loss only after repeated doses, but these threshold shifts were temporary. Therefore, cyclodextrin-induced hearing loss was complex, involving cell death and other more subtle influences on cochlear physiology.
3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (‘rapid prototyping’) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ‘carbomorph’ and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.
The appearance of large-conductance, calcium-activated potassium (BK) current is a hallmark of functional maturation in auditory hair cells. Acquisition of this fast-activating current enables high-frequency, graded receptor potentials in all vertebrates and an electrical tuning mechanism in nonmammals. The gene encoding BK α subunits is highly alternatively spliced, and the resulting variations in channel isoforms may contribute to functional diversity at the onset of hearing. We examined the tissue specificity of nine BK α alternative exons and investigated changes in expression during chick cochlear development using quantitative polymerase chain reaction (qPCR). Each alternative was widely expressed in several tissues except for an insert near the C-terminus Ca2+ sensing domain, which appeared brain-specific. The only alternative form in the membrane-bound core of the channel was expressed in brain and muscle but was undetected in cochlea. Of the remaining variants, three increased in expression prior to the onset of hearing and acquisition of BK currents. These three variants cause decreased Ca2+ sensitivity or increased intracellular retention, traits that would not easily explain the advent of calcium-sensitive currents at embryonic day (E)18–19. Expression levels of other variants were mature and stable by E15, days before currents were acquired. Surface expression of C-terminal isoforms was examined using patch-clamp electrophysiology and immunocytochemistry. C-terminal variants that exhibit robust surface expression appeared in the membrane at E18, even though transcripts were unchanged during development starting from E12. These results indicate that delays in protein synthesis and trafficking/scaffolding of channel subunits underlie the late acquisition of BK currents in cochlear hair cells.
Maxi-K; BKCa; basilar papilla; hair cell; alternative exon
Isolated tubal torsion is a rare event. The clinical presentation is often nonspecific and the diagnosis is difficult, especially in the gravida abdomen. If left untreated, torsion can result in premature labour and foetal loss, as well as maternal morbidity. Here we present a case of isolated tubal torsion in a primigravida occurring in her third trimester and subsequent successful laparoscopic salpingectomy, rather than laparotomy. We discuss some of the diagnostic difficulties faced and approached to surgery as well as a brief review of the literature. In our case the women went on to successfully complete her pregnancy with no further complications.
Using TLR pathways, primary human cytomegalovirus (HCMV) induces innate responses including the production of inflammatory cytokines. Mounting evidence suggests that LPS recognition by TLR4/MD2/CD14 results in differential utilization of TIRAP-TRAF6 and TRAM-TRIF signaling, thereby leading to transcriptional activation of various cytokine genes. However, relative roles of the TLR4/MD2/CD14 complex and its adaptor proteins TIRAP and TRAM involved in regulating monocyte responses to HCMV are incomplete. Here, we provided evidence supporting the notion that the TLR4/MD2/CD14 complex contributes notably to HCMV-induced signaling and subsequent cytokine production in monocytes. In particular, induction of both IL-6 and IL-8 is associated with elevated TIRAP and reduced TRAM mRNA expression. The latter may serve in a compensatory pathway that yields a robust IFN response when TIRAP signaling is blocked in monocytes incubated with Toledo strain HCMV. Inhibitory studies using antisense oligonucleotides or neutralizing antibodies indicate that IL-6 induction by TLR4/MD2 complex is important for the activation of endogenous CD14 which later acts in concert or synergy with TLR4/MD2 as a factor resulting in IL-8 gene expression. We further show that exogenous recombinant CD14 can potentiate innate immune response via TLR4-dependent and possibly via TLR9-dependent pathways to promote enhanced expression/production of IL-8 and IFN-β, respectively.
Despite the availability of effective vaccines, Japanese encephalitis virus (JEV) infections remain a leading cause of encephalitis in many Asian countries. The virus is transmitted to humans by Culex mosquitoes, and, while the majority of human infections are asymptomatic, up to 30% of JE cases admitted to hospital die and 50% of the survivors suffer from neurological sequelae. Microglia are brain-resident macrophages that play key roles in both the innate and adaptive immune responses in the CNS and are thus of importance in determining the pathology of encephalitis as a result of JEV infection.
Cholangiocarcinoma (CC) is increasing in incidence, but its pathogenesis remains poorly understood. Chronic inflammation of the bile duct and cholestasis are major risk factors, but most cases in the West are sporadic. Genetic polymorphisms in biliary transporter proteins have been implicated in benign biliary disease and, in the case of progressive familial cholestasis, have been associated with childhood onset of CC. In the current study, five biologically plausible candidate genes were investigated: ABCB11 (BSEP), ABCB4 (MDR3), ABCC2 (MRP2), ATP8B1 (FIC1) and NR1H4 (FXR).
DNA was collected from 172 Caucasian individuals with confirmed CC. A control cohort of healthy Caucasians was formed. Seventy-three SNPs were selected using the HapMap database to capture genetic variation around the five candidate loci. Genotyping was undertaken with a competitive PCR-based system. Confirmation of Hardy-Weinberg equilibrium and Cochran-Armitage trend testing were performed using PLINK. Haplotype frequencies were compared using haplo.stats.
All 73 SNPs were in Hardy-Weinberg equilibrium. Four SNPs in ABCB11 were associated with altered susceptibility to CC, including the V444A polymorphism, but these associations did not retain statistical significance after Bonferroni correction for multiple testing. Haplotype analysis of the genotyped SNPs in ATP8B1 identified significant differences in frequencies between cases and controls (global p value of 0.005).
Haplotypes in ATP8B1 demonstrated a significant difference between CC and control groups. There was a trend towards significant association of V444A with CC. Given the biological plausibility of polymorphisms in ABCB11 and ATP8B1 as risk modifiers for CC, further study in a validation cohort is required.
Cholangiocarcinoma; Genetics; ABCB11; ABCB4; ABCC2; ATP8B1; NR1H4
Chikungunya virus (CHIKV) is a recently re-emerged public health problem in many countries bordering the Indian Ocean and elsewhere. Chikungunya fever is a relatively self limiting febrile disease, but the consequences of chikungunya fever can include a long lasting, debilitating arthralgia, and occasional neurological involvement has been reported. Macrophages have been implicated as an important cell target of CHIKV with regards to both their role as an immune mediator, as well evidence pointing to long term viral persistence in these cells. Microglial cells are the resident brain macrophages, and so this study sought to define the proteomic changes in a human microglial cell line (CHME-5) in response to CHIKV infection. GeLC-MS/MS analysis of CHIKV infected and mock infected cells identified some 1455 individual proteins, of which 90 proteins, belonging to diverse cellular pathways, were significantly down regulated at a significance level of p<0.01. Analysis of the protein profile in response to infection did not support a global inhibition of either normal or IRES-mediated translation, but was consistent with the targeting of specific cellular pathways including those regulating innate antiviral mechanisms.
Ischemic stroke is a significant health problem affecting over 6 million people in the United States alone. In addition to surgical and thrombolytic therapeutic strategies for stroke, neuroprotective therapies may offer additional benefit. N-acylethanolamines (NAEs) are signaling lipids whose synthesis is upregulated in response to ischemia, suggesting that they may be neuroprotective. To date only three NAEs, arachidonylethanolamide (NAE 20:4), palmitoylethanolamide (NAE 16:0) and oleoylethanolamide (NAE 18:1) have shown to exert neuroprotective effect in animal models for stroke. Here, we describe neuroprotective effects of the hitherto uncharacterized NAEs, lauroylethanolamide (NAE 12:0) and linoleoylethanolamide (NAE 18:2) in a middle cerebral artery occlusion model of stroke. Pretreatment with NAE 18:2 prior to ischemia/reperfusion (I/R) injury resulted in both significantly reduced cortical infarct volume and improved functional outcome as determined using the neurological deficit score. NAE 12:0 improved neurological deficits without a significant reduction lesion size. Our results suggest that NAEs, as a whole, provide neuroprotection during I/R injury and may have therapeutic benefit when used as complementary treatment with other therapies to improve stroke outcome.
N-acylethanolamine; neuroprotection; middle cerebral artery occlusion; ischemia
Emerging evidence increasingly illustrates the importance of a holistic, rather than taxon-specific, approach to the study of ecological communities. Considerable resources are expended to manage both introduced and native mammalian carnivores to improve conservation outcomes; however, management can result in unforeseen and sometimes catastrophic outcomes. Varanid lizards are likely to be apex- or mesopredators, but being reptiles are rarely considered by managers and researchers when investigating the impacts of mammalian carnivore management. Instances of mesopredator release have been described for Varanus gouldii as a result of fox and cat management in Australia, with cascading effects on faunal community structure. A meta-analysis showing extensive dietary niche overlap between varanids, foxes and cats plus a review of experimental and circumstantial evidence suggests mesopredator release of V. gouldii and about five other medium to large species of varanid lizard is likely in other regions. This highlights the need for managers to adopt a whole-of-community approach when attempting to manage predators for sustained fauna conservation, and that additional research is required to elucidate whether mesopredator release of varanids is a widespread consequence of carnivore management, altering the intended faunal responses.
dietary niche overlap; exploitation competition; intraguild predation; introduced predator management; trophic cascade; Varanus
Dysregulation of Ca2+ signaling following oxidative stress is an important pathophysiological mechanism of many chronic neurodegenerative disorders, including Alzheimer’s Disease, age-related macular degeneration, glaucomatous and diabetic retinopathies. However, the underlying mechanisms of disturbed intracellular Ca2+ signaling remain largely unknown. We here describe a novel mechanism for increased intracellular Ca2+ release following oxidative stress in a neuronal cell line. Using an experimental approach that included quantitative polymerase chain reaction, quantitative immunoblotting, microfluorimetry and the optical imaging of intracellular Ca2+ release, we show that sub-lethal tert-butyl hydroperoxide-mediated oxidative stress result in a selective up-regulation of type-2 inositol-1,4,5,-trisphophate receptors. This oxidative stress mediated change was detected both at the transcriptional and translational level and functionally resulted in increased Ca2+ release into the nucleoplasm from the membranes of the nuclear envelope at a given receptor-specific stimulus. Our data describe a novel source of Ca2+ dysregulation induced by oxidative stress with potential relevance for differential subcellular Ca2+ signaling specifically within the nucleus and the development of novel neuroprotective strategies in neurodegenerative disorders.
Functional (psychogenic or somatoform) symptoms are common in neurology clinics. Cognitive-behavioral therapy (CBT) can be an effective treatment, but there are major obstacles to its provision in practice. We tested the hypothesis that adding CBT-based guided self-help (GSH) to the usual care (UC) received by patients improves outcomes.
We conducted a randomized trial in 2 neurology services in the United Kingdom. Outpatients with functional symptoms (rated by the neurologist as “not at all” or only “somewhat” explained by organic disease) were randomly allocated to UC or UC plus GSH. GSH comprised a self-help manual and 4 half-hour guidance sessions. The primary outcome was self-rated health on a 5-point clinical global improvement scale (CGI) at 3 months. Secondary outcomes were measured at 3 and 6 months.
In this trial, 127 participants were enrolled, and primary outcome data were collected for 125. Participants allocated to GSH reported greater improvement on the primary outcome (adjusted common odds ratio on the CGI 2.36 [95% confidence interval 1.17–4.74; p = 0.016]). The absolute difference in proportion “better” or “much better” was 13% (number needed to treat was 8). At 6 months the treatment effect was no longer statistically significant on the CGI but was apparent in symptom improvement and in physical functioning.
CBT-based GSH is feasible to implement and efficacious. Further evaluation is indicated.
Classification of evidence:
This study provides Class III evidence that CBT-based GSH therapy improves self-reported general health, as measured by the CGI, in patients with functional neurologic symptoms.
Chikungunya virus (CHIKV) is a re-emerging mosquito borne alphavirus that has caused large scale epidemics in the countries around the Indian Ocean, as well as leading to autochthonous transmission in some European countries. The transmission of the disease has been driven by the emergence of an African lineage of CHIKV with enhanced transmission and dissemination in Aedes mosquito hosts. Two main genotypes of this lineage have been circulating, characterized by the presence of a substitution of a valine for an alanine at position 226 of the E1 protein. The outbreak, numbering in millions of cases in the infected areas, has been associated with increasing numbers of cases with non-classical presentation including encephalitis and meningitis. This study sought to compare the original Ross strain with two isolates from the recent outbreak of chikungunya fever in respect of infectivity and the induction of apoptosis in eight mammalian cell lines and two insect cell lines, in addition to generating a comprehensive virus production profile for one of the newer isolates. Results showed that in mammalian cells there were few differences in either tropism or pathogenicity as assessed by induction of apoptosis with the exception of Hela cells were the recent valine isolate showed less infectivity. The Aedes albopictus C6/36 cell line was however significantly more permissive for both of the more recent isolates than the Ross strain. The results suggest that the increased infectivity seen in insect cells derives from an evolution of the CHIKV genome not solely associated with the E1:226 substitution.
Development of visual system circuitry requires the formation of precise synaptic connections between neurons in the retina and brain. For example, retinal ganglion cells (RGCs) form synapses onto neurons within subnuclei of the lateral geniculate nucleus (LGN) – i.e. the dorsal LGN (dLGN), ventral LGN (vLGN) and intergeniculate leaflet (IGL). Distinct classes of RGCs project to these subnuclei: the dLGN is innervated by image-forming RGCs, while the vLGN and IGL are innervated by non-image-forming RGCs. To explore potential mechanisms regulating class-specific LGN targeting we sought to identify differentially expressed targeting molecules in these LGN subnuclei. One candidate targeting molecule enriched in the vLGN and IGL during retinogeniculate circuit formation was the extracellular matrix molecule reelin. Anterograde labeling of RGC axons in mutant mice lacking functional reelin (relnrl/rl) revealed reduced patterns of vLGN and IGL innervation and misrouted RGC axons in adjacent non-retino-recipient thalamic nuclei. Using genetic reporter mice, we further demonstrated that mistargeted axons were from non-image-forming, intrinsically-photosensitive RGCs (ipRGCs). In contrast to mistargeted ipRGC axons, axons arising from image-forming RGCs and layer VI cortical neurons correctly targeted the dLGN in relnrl/rl mutants. Taken together, these data reveal reelin is essential for the targeting of LGN subnuclei by functionally distinct classes of RGCs.
synaptic targeting; axon guidance; retinal ganglion cell; thalamus; extracellular matrix; melanopsin
Calcium flux through L-type voltage-activated calcium (Cav1) channels is crucial for regulating brain functions including memory formation and behavior. Alterations in Ca2+ homeostasis have been linked to many cognitive disorders and understanding into the regulation of this process is crucial for their remedy. Therefore, here, we have evaluated the effect of a multifunctional protein known to be involved in memory functions called regulator of G protein signaling-14 (RGS-14) on Cav1 channel activity in neuronal cell lines NG108-15 and SH-SY5Y. RGS-14 protein produced significant reduction in Ca2+ influx in both cell lines and this effect was dependent on nifedipine-sensitive Cav1 channels. Thus, our results provide evidence supporting the idea that RGS-14 may facilitate the cognitive processing by modulating Cav1 channel-mediated intracellular Ca2+ transients.
Ca2+ influx; L-type voltage-activated calcium channels; Cav1 channels; RGS-14 protein; Neuronal cell lines
To determine the risk of epileptic seizures due to a brain arteriovenous malformation (AVM) or cavernous malformation (CM).
In a prospective population-based study of new diagnoses of AVMs (n = 229) or CMs (n = 139) in adults in Scotland in 1999–2003, we used annual medical records surveillance, general practitioner follow-up, and patient questionnaires to quantify the risk of seizures between clinical presentation and AVM/CM treatment, last follow-up, or death.
The 5-year risk of first-ever seizure after presentation was higher for AVMs presenting with intracranial hemorrhage or focal neurologic deficit (ICH/FND: n = 119; 23%, 95% confidence interval [CI] 9%–37%) than for incidental AVMs (n = 40; 8%, 95% CI 0%–20%), CMs presenting with ICH/FND (n = 38; 6%, 95% CI 0%–14%), or incidental CMs (n = 57; 4%, 95% CI 0%–10%). For adults who had never experienced ICH/FND, the 5-year risk of epilepsy after first-ever seizure was higher for CMs (n = 23; 94%, 95% CI 84%–100%) than AVMs (n = 37; 58%, 95% CI 40%–76%; p = 0.02). Among adults who never experienced ICH/FND and presented with or developed epilepsy, there was no difference in the proportions achieving 2-year seizure freedom over 5 years between AVMs (n = 43; 45%, 95% CI 20%–70%) and CMs (n = 35; 47%, 95% CI 27%–67%).
AVM-related ICH confers a significantly higher risk of a first-ever seizure compared to CMs or incidental AVMs. Adults with a CM have a high risk of epilepsy after a first-ever seizure but achieve seizure freedom as frequently as those with epilepsy due to an AVM.
The influence of membrane cholesterol content on a variety of ion channel conductances in numerous cell models has been shown, but studies exploring its role in auditory hair cell physiology are scarce. Recent evidence shows that cholesterol depletion affects outer hair cell electromotility and the voltage-gated potassium currents underlying tall hair cell development, but the effects of cholesterol on the major ionic currents governing auditory hair cell excitabilityare unknown. We investigated the effects of a cholesterol-depleting agent (methyl beta cyclodextrin, MβCD) on ion channels necessary for the early stages of sound processing. Large-conductance BK-type potassium channels underlie temporal processing and open in a voltage- and calcium-dependent manner. Voltage-gated calcium channels (VGCCs) are responsible for calcium-dependent exocytosis and synaptic transmission to the auditory nerve. Our results demonstrate that cholesterol depletion reduced peak steady-state calcium-sensitive (BK-type) potassiumcurrent by 50% in chick cochlear hair cells. In contrast, MβCD treatment increased peak inward calcium current (∼30%), ruling out loss of calcium channel expression or function as a cause of reduced calcium-sensitive outward current. Changes in maximal conductance indicated a direct impact of cholesterol on channel number or unitary conductance. Immunoblotting following sucrose-gradient ultracentrifugation revealed BK expression in cholesterol-enriched microdomains. Both direct impacts of cholesterol on channel biophysics, as well as channel localization in the membrane, may contribute to the influence of cholesterol on hair cell physiology. Our results reveal a new role for cholesterol in the regulation of auditory calcium and calcium-activated potassium channels and add to the growing evidence that cholesterol is a key determinant in auditory physiology.
A novel ArsR-SmtB family transcriptional repressor, KmtR, has been characterized from mycobacteria. Mutants of Mycobacterium tuberculosis lacking kmtR show elevated expression of Rv2025c encoding a deduced CDF-family metal exporter. KmtR-dependent repression of the cdf and kmtR operator-promoters was alleviated by nickel and cobalt in minimal medium. Electrophoretic mobility shift assays and fluorescence anisotropy show binding of purified KmtR to nucleotide sequences containing a region of dyad symmetry from the cdf and kmtR operator-promoters. Incubation of KmtR with cobalt inhibits DNA complex assembly and metal-protein binding was confirmed. KmtR is the second, to NmtR, characterized ArsR-SmtB sensor of nickel and cobalt from M. tuberculosis suggesting special significance for these ions in this pathogen. KmtR-dependent expression is elevated in complete medium with no increase in response to metals, whereas NmtR retains a response to nickel and cobalt under these conditions. KmtR has tighter affinities for nickel and cobalt than NmtR consistent with basal levels of these metals being sensed by KmtR but not NmtR in complete medium. More than a thousand genes encoding ArsR-SmtB-related proteins are listed in databases. KmtR has none of the previously defined metal-sensing sites. Substitution of His88, Glu101, His102, His110, or His111 with Gln generated KmtR variants that repress the cdf and kmtR operator-promoters even in elevated nickel and cobalt, revealing a new sensory site. Importantly, ArsR-SmtB sequence groupings do not correspond with the different sensory motifs revealing that only the latter should be used to predict metal sensing.
Retinal ganglion cell (RGC) death is a hallmark of neurodegenerative diseases and disease processes of the eye, including glaucoma. The protection of RGCs has been an important strategy for combating glaucoma, but little clinical success has been reported to date. One pathophysiological consequence of glaucoma is excessive extracellular glutamate subsequently leading to excitotoxicity in the retina. Endocannabinoids, such as the N-acylethanolamine (NAE), arachidonylethanolamine (NAE 20:4), exhibit neuroprotective properties in some models of neurodegenerative disease. The majority of NAEs, however, are not cannabinoids, and their physiological function is not clear. Here, we determined whether the noncannabinoid NAE, linoleoylethanolamine (NAE18:2), protects neurons in the RGC layer against glutamate excitotoxicity in ex-vivo retina cultures. Using a terminal deoxynucleotidyl transferase-mediated dUTP (2′-deoxyuridine 5′-triphosphate) nick-end labeling (TUNEL) assay, we determined that NAE18:2 reduces the number of apoptotic RGC layer neurons in response to glutamate and conclude that NAE18:2 is a neuroprotective compound with potential for treating glaucomatous retinopathy.
neuroprotection; glutamate; calcium signaling; immunocytochemistry; eye; vision; glaucoma
N-acylethanolamines (NAEs) are endogenous lipids that are synthesized in response to tissue injury, including ischemia and stroke, suggesting they may exhibit neuroprotective properties. We hypothesized that NAE 16:0 (palmitoylethanolemine) is neuroprotective against ischemia-reperfusion injury in rats, a widely employed model of stroke, and that neuroprotection is mediated through an intracellular mechanism independent of known NAE receptors. Administration of NAE 16:0 from 30 min. before to 2 hrs after stroke significantly reduced cortical and subcortical infarct volume, and correlated with an improvement of the neurological phenotype, as assessed by the neurological deficit score. We here show that NAE 16:0-mediated neuroprotection was independent of cannabinoid (CB1) and vanilloid (VR1) receptor activation, known NAE receptors on the plasma membrane, as determined by inclusion of specific inhibitors. The inclusion of an NAE uptake inhibitor (AM404), however, completely reversed NAE 16:0-mediated neuroprotection, suggesting that NAE 16:0’s effects are through an intracellular mechanism. NAE 16:0 produced a significant reduction in the number of cells undergoing apoptosis and reversed ischemia-induced up-regulation of several proteins, including inducible nitric oxide synthase and transcription factor NFκB. Our findings suggest that NAE 16:0-mediated neuroprotection is due to the reduction of neuronal apoptosis and inflammation in the brain.
neurodegeneration; neuroprotection; receptors; ischemia
Both acute and chronic degenerative diseases of the nervous system reduce the viability and function of neurons through changes in intracellular calcium signaling. In particular, pathological increases in the intracellular calcium concentration promote such pathogenesis. Disease involvement of numerous regulators of intracellular calcium signaling located on the plasma membrane and intracellular organelles has been documented. Diverse groups of chemical compounds targeting ion channels, G-protein coupled receptors, pumps and enzymes have been identified as potential neuroprotectants. The present review summarizes the discovery, mechanisms and biological activity of neuroprotective molecules targeting proteins that control intracellular calcium signaling to preserve or restore structure and function of the nervous system. Disease relevance, clinical applications and new technologies for the identification of such molecules are being discussed.
calcium; Ca2+; intracellular calcium channel; ion channel; extracellular; intracellular; accessory proteins; associated proteins; G-protein coupled receptors; imaging; microscopy; signaling; neuroprotection; cytoprotection; neurodegeneration; Alzheimer's disease; Huntington's disease; retina
Avian hepatitis E virus (avian HEV) is the primary causative agent of Hepatitis-Splenomegaly (HS) syndrome in chickens. Recently, a genetically unique strain of avian HEV, designated avian HEV-VA, was recovered from healthy chickens in Virginia. The objective of this study was to experimentally compare the pathogenicity of the prototype strain recovered from a chicken with HS syndrome and the avian HEV-VA strain in specific-pathogen-free chickens. An infectious stock of the avian HEV-VA strain was first generated and its infectivity titer determined in chickens. For the comparative pathogenesis study, fifty-four chickens of 6-week-old were assigned to 3 groups of 18 chickens each. The group 1 chickens were each intravenously inoculated with 5×102.5 50% chicken infectious dose of the prototype strain. The group 2 received the same dose of the avian HEV-VA strain, and the group 3 served as negative controls. Six chickens from each group were necropsied at 2, 3 and 4 weeks post-inoculation (wpi). Most chickens in both inoculated groups seroconverted by 3 wpi, and the mean anti-avian HEV antibody titers were higher for the prototype strain group than the avian HEV-VA strain group. There was no significant difference in the patterns of viremia and fecal virus shedding. Blood analyte profiles did not differ between treatment groups except for serum creatine phosphokinase levels which were higher for prototype avian HEV group than avian HEV-VA group. The hepatic lesion score was higher for the prototype strain group than the other two groups. The results indicateded that the avian HEV-VA strain is only slightly attenuated compared to the prototype strain, suggesting that the full-spectrum of HS syndrome is likely associated with other co-factors.