Validation of an Algorithm to Predict the Likelihood of an 8/8 HLA-Matched Unrelated Donor at Search Initiation.

A strategy to rapidly determine if a matched unrelated donor (URD) can be secured for allograft recipients is needed. We sought to validate the accuracy of (1) HapLogic match predictions and (2) a resultant novel Search Prognosis (SP) patient categorization that could predict 8/8 HLA-matched URD(s) likelihood at search initiation. Patient prognosis categories at search initiation were correlated with URD confirmatory typing results. HapLogic-based SP categorizations accurately predicted the likelihood of an 8/8 HLA-match in 830 patients (1530 donors tested). Sixty percent of patients had 8/8 URD(s) identified. Patient SP categories (217 very good, 104 good, 178 fair, 33 poor, 153 very poor, 145 futile) were associated with a marked progressive decrease in 8/8 URD identification and transplantation. Very good to good categories were highly predictive of identifying and receiving an 8/8 URD regardless of ancestry. Europeans in fair/poor categories were more likely to identify and receive an 8/8 URD compared with non-Europeans. In all ancestries very poor and futile categories predicted no 8/8 URDs. HapLogic permits URD search results to be predicted once patient HLA typing and ancestry is obtained, dramatically improving search efficiency. Poor, very poor, andfutile searches can be immediately recognized, thereby facilitating prompt pursuit of alternative donors.

Prospective Evaluation of Unrelated Donor Cord Blood and Haploidentical Donor Access Reveals Graft Availability Varies by Patient Ancestry: Practical Implications for Donor Selection.

The availability of cord blood (CB) and haploidentical (haplo) donors in all patient populations is not established. We have investigated the addition of haplo-CD34+ cells to CB grafts (haplo-CBT) to speed myeloid engraftment. Thus, we have prospectively assessed CB and haplo donor availability in adult patients without 8/8 HLA-allele matched unrelated donors (URDs). Analysis of 89 patients eligible for haplo-CBT revealed 4 distinct patient groups. First, 6 patients (7% of total, 33% non-European) underwent CBT only as they had no suitable family members to type. In group 2, 49 patients (45% non-European) received haplo-CBT using the first haplo donor chosen. Group 3 (n = 21, 76% non-European) underwent CBT with/without haplo. In this group, the first haplo donor chosen failed clearance in 20 patients and transplantation was too urgent to permit donor evaluation in 1. Fifty-three haplo donors were evaluated (2 to 6 per patient) for 21 group 3 patients, and 43 of 53 (81%) haplos failed clearance for predominantly medical and/or psychosocial reasons. Group 4, (n = 13, 85% non-European with a high median weight of 96 kilograms) had no CB grafts with/without no haplo donors. Overall, African patients had the worst donor availability with only 65% having a suitable CB graft and only 44% having a suitable haplo donor. Additionally, in non-European patients, a greater number of haplos required evaluation/patient to secure a suitable haplo graft. Although these data should be confirmed in a larger study, it suggests that there are barriers to the availability of both CB and haplo grafts in adult patients without 8/8 URDs, especially in those with African ancestry, and has multiple practical implications for patient management.

Nicotine exacerbates brain edema during in vitro and in vivo focal ischemic conditions.

We have previously shown that nicotine, the addictive component of tobacco products, alters the blood-brain barrier (BBB) Na(+),K(+),2Cl(-) cotransporter (NKCC) during in vitro hypoxia-aglycemia exposure. Attenuation of abluminal NKCC suggests that accumulation of ions in the brain extracellular fluid would result in an increase of fluid or cytotoxic edema in the brain during hypoxia-aglycemia or stroke conditions. To further investigate whether nicotine products have the potential to worsen stroke outcome by increasing edema formation, two separate models to mimic stroke conditions were utilized to decipher the effects of short-term and long-term administrations of nicotine products on brain edema following stroke. Oxygen glucose deprivation (OGD) was studied in rat hippocampal slices with short-term or long-term exposure to nicotine and cigarette smoke constituents. During short-term exposure, the presence of nicotine at a concentration mimicking heavy smokers increased water content of hippocampal slices during OGD. Furthermore, long-term 1-week administration of nicotine increased water content in hippocampal slices that could be attenuated with nicotine acetylcholine receptor (nAChR) antagonists, suggesting nicotine increase edema during OGD via nAChRs. A second model of focal ischemia, middle cerebral artery occlusion, showed an increase of infarct size during short-term exposure to nicotine and an increase of edema during both short-term and long-term administration of nicotine, compared with saline controls. These findings support the paradigm that nicotine products not only increase the incidence of stroke but also have the potential to worsen stroke outcome by increased edema formation.

Amyloid plaque and neurofibrillary tangle pathology in a regulatable mouse model of Alzheimer's disease.

Transgenic mouse models that independently express mutations in amyloid precursor protein (APP) and tau have proven useful for the study of the neurological consequences of amyloid-beta (Abeta) plaque and neurofibrillary tangle pathologies. Studies using these mice have yielded essential discoveries with regard to specific aspects of neuronal dysfunction and degeneration that characterize the brain during Alzheimer's disease (AD) and other age-dependent tauopathies. Most recent transgenic studies have focused on the creation of regulatable models that allow the temporal control of transgene expression. To study a more complete model of AD pathology, we designed a new regulatable transgenic mouse that harbors both APP and tau transgenes. Here, we present a novel transgenic mouse model, rTg3696AB, which expresses human APP(NLI) and tau(P301L) driven by the CaMKII promoter system. Subsequent generation of Abeta and 4R0N tau in the brain resulted in the development of three neuropathological features of AD: Abeta plaques, neurofibrillary tangles, and neurodegeneration. Importantly, transgene expression in these mice is regulatable, permitting temporal control of gene expression and the investigation of transgene suppression.

Age-dependent neurofibrillary tangle formation, neuron loss, and memory impairment in a mouse model of human tauopathy (P301L).

Here, we describe the generation of a novel transgenic mouse model of human tauopathy. The rTg(tau(P301L))4510 mouse expresses the P301L mutation in tau (4R0N) associated with frontotemporal dementia and parkinsonism linked to chromosome 17. Transgene expression was driven by a forebrain-specific Ca(2+) calmodulin kinase II promoter system resulting in high levels of expression in the hippocampus and neocortex. Importantly, transgene expression in this model is induced via the tetracycline-operon responsive element and is suppressed after treatment with doxycycline. Continued transgene expression in rTg(tau(P301L))4510 mice results in age-dependent development of many salient characteristics of hereditary human dementia. From an early age, immunohistochemical studies demonstrated abnormal biochemical processing of tau and the presence of pathological conformation- and phosphorylation-dependent epitopes. Neurofibrillary tangle (NFT) pathology was first observed in the neocortex and progressed into the hippocampus and limbic structures with increasing age. Consistent with the formation of NFTs, immunoblots indicated an age-dependent transition of accumulating tau species from Sarkosyl soluble 55 kDa to insoluble hyperphosphorylated 64 kDa. Ultrastructural analysis revealed the presence of straight tau filaments. Furthermore, the effects of tau(P301L) expression on spatial reference memory were longitudinally tested using the Morris water maze. Compared with nontransgenic age-matched control littermates, rTg(tau(P301L))4510 mice developed significant cognitive impairments from 4 months of age. Memory deficits were accompanied by gross forebrain atrophy and a prominent loss of neurons, most strikingly in hippocampal subdivision CA1. Collectively, these data describe a novel transgenic mouse that closely mimics human tauopathy and may represent an important model for the future study of tau-related neurodegenerative disease.

Altered inflammatory activity associated with reduced hippocampal volume and more severe posttraumatic stress symptoms in Gulf War veterans.

BACKGROUND: Inflammation may reduce hippocampal volume by blocking neurogenesis and promoting neurodegeneration. Posttraumatic stress disorder (PTSD) has been linked with both elevated inflammation and reduced hippocampal volume. However, few studies have examined associations between inflammatory markers and hippocampal volume, and none have examined these associations in the context of PTSD. METHODS: We measured levels of the inflammatory markers interleukin-6 (IL-6) and soluble receptor II for tumor necrosis factor (sTNF-RII) as well as hippocampal volume in 246 Gulf War veterans with and without current and past PTSD as assessed with the Clinician Administered PTSD Scale (CAPS). Enzyme-linked immunosorbent assays were used to measure inflammatory markers, and 1.5Tesla magnetic resonance imaging (MRI) and Freesurfer version 4.5 were used to quantify hippocampal volume. Hierarchical linear regression and analysis of covariance models were used to examine if hippocampal volume and PTSD status would be associated with elevated levels of IL-6 and sTNF-RII. RESULTS: Increased sTNF-RII, but not IL-6, was significantly associated with reduced hippocampal volume (ß=-0.14, p=0.01). The relationship between sTNF-RII and hippocampal volume was independent of potential confounds and covariates, including PTSD status. Although we observed no PTSD diagnosis-related differences in either IL-6 or sTNF-RII, higher PTSD severity was associated with significantly increased sTNF-RII (ß=0.24, p=0.04) and reduced IL-6 levels (ß=-0.24, p=0.04). CONCLUSIONS: Our results indicate that specific inflammatory proteins may be associated with brain structure and function as indexed by hippocampal volume and PTSD symptoms.

Characterization of a Novel Mouse Model of Alzheimer's Disease--Amyloid Pathology and Unique ß-Amyloid Oligomer Profile.

Amyloid plaques composed of ß-amyloid (Aß) protein are a pathological hallmark of Alzheimer's disease. We here report the generation and characterization of a novel transgenic mouse model of Aß toxicity. The rTg9191 mice harbor a transgene encoding the 695 amino-acid isoform of human amyloid precursor protein (APP) with the Swedish and London mutations (APPNLI) linked to familial Alzheimer's disease, under the control of a tetracycline-response element, as well as a transgene encoding the tetracycline transactivator, under the control of the promoter for calcium-calmodulin kinase IIα. In these mice, APPNLI is expressed at a level four-fold that of endogenous mouse APP and its expression is restricted to forebrain regions. Transgene expression was suppressed by 87% after two months of doxycycline administration. Histologically, we showed that (1) Aß plaques emerged in cerebral cortex and hippocampus as early as 8 and 10.5-12.5 months of age, respectively; (2) plaque deposition progressed in an age-dependent manner, occupying up to 19% of cortex at ~25 months of age; and (3) neuropathology--such as abnormal neuronal architecture, tau hyperphosphorylation and misfolding, and neuroinflammation--was observed in the vicinity of neuritic plaques. Biochemically, we determined total Aß production at varied ages of mice, and we showed that mice produced primarily fibrillar Aß assemblies recognized by conformation-selective OC antibodies, but few non-fibrillar oligomers (e.g., Aß*56) detectable by A11 antibodies. Finally, we showed that expression of the tetracycline transactivator resulted in reduced brain weight and smaller dentate-gyrus size. Collectively, these data indicate that rTg9191 mice may serve as a model for studying the neurological effects of the fibrillar Aß assemblies in situ.

CLOCK in breast tumorigenesis: genetic, epigenetic, and transcriptional profiling analyses.

The transcription factors responsible for maintaining circadian rhythm influence a variety of biological processes. Recently, it has been suggested that the core circadian genes may play a role in breast tumorigenesis, possibly by influencing hormone regulation or other pathways relevant to cancer. To evaluate this hypothesis, we conducted a genetic and epigenetic association study, as well as a transcriptional profiling array and a pathway-based network analysis. We report significant correlations between single nucleotide polymorphisms associated with the central circadian regulator CLOCK and breast cancer risk, with apparent effect modification by estrogen receptor/progesterone receptor status. We also found that hypermethylation in the CLOCK promoter reduced the risk of breast cancer, and lower levels of CLOCK expression were documented in healthy controls relative to normal or tumor tissue from patients with breast cancer. Finally, we silenced CLOCK in vitro and performed a whole-genome expression microarray and pathway analysis, which identified a cancer-relevant network of transcripts with altered expression following CLOCK gene knockdown. Our findings support the hypothesis that circadian genes influence tumorigenesis, and identify a set of circadian gene variants as candidate breast cancer susceptibility biomarkers.

APC/C-Cdh1-mediated degradation of the Polo kinase Cdc5 promotes the return of Cdc14 into the nucleolus.

In the budding yeast Saccharomyces cerevisiae, the protein phosphatase Cdc14 triggers exit from mitosis by promoting the inactivation of cyclin-dependent kinases (CDKs). Cdc14's activity is controlled by Cfi1/Net1, which holds and inhibits the phosphatase in the nucleolus from G1 until metaphase. During anaphase, two regulatory networks, the Cdc14 Early Anaphase Release (FEAR) network and the Mitotic Exit Network (MEN), promote the dissociation of Cdc14 from its inhibitor, allowing the phosphatase to reach its targets throughout the cell. The molecular circuits that trigger the return of Cdc14 into the nucleolus after the completion of exit from mitosis are not known. Here we show that activation of a ubiquitin ligase known as the Anaphase-Promoting Complex or Cyclosome (APC/C) bound to the specificity factor Cdh1 triggers the degradation of the Polo kinase Cdc5, a key factor in releasing Cdc14 from its inhibitor in the nucleolus.

A semisynthetic epitope for kinase substrates.

The ubiquitous nature of protein phosphorylation makes it challenging to map kinase-substrate relationships, which is a necessary step toward defining signaling network architecture. To trace the activity of individual kinases, we developed a semisynthetic reaction scheme, which results in the affinity tagging of substrates of the kinase in question. First, a kinase, engineered to use a bio-orthogonal ATPgammaS analog, catalyzes thiophosphorylation of its direct substrates. Second, alkylation of thiophosphorylated serine, threonine or tyrosine residues creates an epitope for thiophosphate ester-specific antibodies. We demonstrated the generality of semisynthetic epitope construction with 13 diverse kinases: JNK1, p38alpha MAPK, Erk1, Erk2, Akt1, PKCdelta, PKCepsilon, Cdk1/cyclinB, CK1, Cdc5, GSK3beta, Src and Abl. Application of this approach, in cells isolated from a mouse that expressed endogenous levels of an analog-specific (AS) kinase (Erk2), allowed purification of a direct Erk2 substrate.

Tobacco smoke chemicals attenuate brain-to-blood potassium transport mediated by the Na,K,2Cl-cotransporter during hypoxia-reoxygenation.

Smoking tobacco, including cigarettes, has been associated with an increased incidence and relative risk for cerebral infarction in both men and women. Recently, we have shown that nicotine and cotinine attenuate abluminal (brain facing) K(+) uptake mediated by the Na,K,2Cl-cotransporter (NKCC) in bovine brain microvessel endothelial cells (BBMECs) after hypoxic/aglycemic exposure (stroke conditions). The purpose of the current study was to explore the effects of nicotine and tobacco smoke chemicals on K(+) movement through the blood-brain barrier during both hypoxia/aglycemia and reoxygenation. BBMECs were exposed to nicotine/cotinine, nicotine-containing cigarette smoke extract (N-CSE), or nicotine-free cigarette smoke extract (NF-CSE) in quantities designed to mimic plasma concentrations of smokers. Stroke conditions were mimicked in vitro in BBMECs through 6 h of hypoxia/aglycemia with or without 12 h of reoxygenation, after which NKCC-mediated K(+) uptake and paracellular integrity were measured with (86)Rb and [(14)C]sucrose, respectively. In addition, K(+) concentrations in brain extracellular fluid were estimated in (86)Rb-injected rats that were administered nicotine, N-CSE, or NF-CSE and on whom global ischemia/reperfusion by in vivo four-vessel occlusion was performed. Both in vitro and in vivo paradigms showed nicotine, the major alkaloid present in tobacco smoke, to be the determining factor of an inhibited response of abluminal NKCC in BBMECs during and after stroke conditions. This was measured as a decrease in abluminal brain endothelial cell NKCC activity and as an increase in brain extracellular K(+) concentration measured as the brain extracellular fluid (86)Rb/plasma ratio after in vivo four-vessel occlusion with reperfusion.

The protein kinase Kin4 inhibits exit from mitosis in response to spindle position defects.

Accurate nuclear position is essential for each daughter cell to receive one DNA complement. In budding yeast, a surveillance mechanism known as the spindle position checkpoint ensures that exit from mitosis only occurs when the anaphase nucleus is positioned along the mother-bud axis. We identified the protein kinase Kin4 as a component of the spindle position checkpoint. KIN4 prevents exit from mitosis in cells with mispositioned nuclei by inhibiting the mitotic exit network (MEN), a GTPase signaling cascade that promotes exit from mitosis. Kin4 is active in cells with mispositioned nuclei and predominantly localizes to mother cells, where it is ideally situated to inhibit MEN signaling at spindle pole bodies (SPBs) when anaphase spindle elongation occurs within the mother cell.

A second-site suppressor strategy for chemical genetic analysis of diverse protein kinases.

Chemical genetic analysis of protein kinases involves engineering kinases to be uniquely sensitive to inhibitors and ATP analogs that are not recognized by wild-type kinases. Despite the successful application of this approach to over two dozen kinases, several kinases do not tolerate the necessary modification to the ATP binding pocket, as they lose catalytic activity or cellular function upon mutation of the 'gatekeeper' residue that governs inhibitor and nucleotide substrate specificity. Here we describe the identification of second-site suppressor mutations to rescue the activity of 'intolerant' kinases. A bacterial genetic selection for second-site suppressors using an aminoglycoside kinase APH(3')-IIIa revealed several suppressor hotspots in the kinase domain. Informed by results from this selection, we focused on the beta sheet in the N-terminal subdomain and generated a structure-based sequence alignment of protein kinases in this region. From this alignment, we identified second-site suppressors for several divergent kinases including Cdc5, MEKK1, GRK2 and Pto. The ability to identify second-site suppressors to rescue the activity of intolerant kinases should facilitate chemical genetic analysis of the majority of protein kinases in the genome.

Regulation of blood-brain barrier Na,K,2Cl-cotransporter through phosphorylation during in vitro stroke conditions and nicotine exposure.

Nicotine, a major constituent of tobacco smoke, has important effects on brain recovery after focal ischemia (Wang et al., 1997). The purpose of this work is to systematically test the effects of nicotine during stroke conditions on blood-brain barrier (BBB) potassium transport, protein expression of the Na,K,2Cl-cotransporter (NKCC), and cell signaling pathways that control NKCC activity at the BBB. Confluent bovine brain microvessel endothelial cells (BBMECs) were exposed to both a hypoxic/aglycemic (H/A) environment to model BBB function during stroke conditions and nicotine and cotinine (N/C) to model plasma levels seen in smokers. BBMECs exhibit both Na,K-ATPase and NKCC activity (60 and 34 nmol/min/g, respectively) that contribute to 98% of the K(+) uptake in cultured endothelial cells. An adaptive up-regulation of NKCC activity was identified to occur on the basolateral surface of the BBB after in vitro stroke conditions. Twenty-four hours of N/C exposure, at doses equivalent to plasma levels of smokers, combined with 6 h of H/A, reduced NKCC protein expression and total NKCC activity (shown by bumetanide-sensitive (86)RB uptake) compared with 6 h of H/A alone (P < 0.01). Basolateral K(+) transport was found to be modulated by nicotinic acetylcholine receptors expressed at the BBB. NKCC activity on the basolateral surface of the BBB is controlled by an ongoing phosphorylation/dephosphorylation processes. We have identified a potential mechanism in altered BBB response to stroke conditions with prior N/C exposure directly implicating damage to brain-to-blood K(+) transport mediated at the BBB and perhaps neuronal recovery after stroke.

Cyclodextrins in nasal delivery of low-molecular-weight heparins: in vivo and in vitro studies.

PURPOSE: To test the hypothesis that cyclodextrins reversibly enhance nasal absorption of low-molecular-weight heparins (LMWHs) and to investigate the mechanisms by which cyclodextrins enhance LMWH absorption via the nose. METHODS: Absorption of LMWHs was studied by measuring plasma anti-factor Xa activity after nasal administration of various LMWH formulations to anesthetized rats. In vivo reversibility studies were performed to investigate if the effects of cyclodextrins are reversible and diminish with time. The absorption-enhancing mechanisms of cyclodextrins were investigated in cell culture model. The transport of enoxaparin and mannitol, changes in transepithelial electrical resistance (TEER), and distribution of tight junction protein ZO-1 were investigated. RESULTS: Formulations containing 5% dimethyl-beta-cyclodextrin (DMbetaCD) produced the highest increase in the bioavailability of LMWH preparations tested. In vivo reversibility studies with 5% DMbetaCD showed that the effect of the absorption enhancer at the site of administration diminished with time. Transport studies using 16HBE14o(-) cells demonstrated that the increase in the permeability of enoxaparin and mannitol, reduction in TEER, and the changes in the tight junction protein ZO-1 distribution produced by 5% DMbetaCD were much greater than those produced by beta-cyclodextrin (betaCD) or hydroxyl-propyl-beta-cyclodextrin (HPbetaCD). CONCLUSIONS: Of the cyclodextrins tested, DMbetaCD was the most efficacious in enhancing absorption of LMWHs both in vivo and in vitro. The study also suggests that cyclodextrins enhance nasal drug absorption by opening of cell-cell tight junctions.

In vivo and in vitro assessment of baseline blood-brain barrier parameters in the presence of novel nanoparticles.

PURPOSE: Nanoparticles have advantage as CNS drug delivery vehicles given they disguise drug permeation limiting characteristics. Conflicting toxicological data, however, is published with regard to blood-brain barrier integrity and gross mortality. METHODS: To address this issue two novel nanoparticle types: "emulsifying wax/Brij 78" and "Brij 72/Tween 80 nanoparticles were evaluated in vivo for effect on cerebral perfusion flow, barrier integrity, and permeability using the in situ brain perfusion technique. Additional evaluation was completed in vitro using bovine brain microvessel endothelial cells for effect on integrity, permeability, cationic transport interactions, and tight junction protein expression. RESULTS: In the presence of either nanoparticle formulation, no overall significant differences were observed for cerebral perfusion flow in vivo. Furthermore, observed in vitro and in vivo data showed no statistical changes in barrier integrity, membrane permeability, or facilitated choline transport. Western blot analyses of occludin and claudin-1 confirmed no protein expression changes with incubation of either nanoparticle. CONCLUSIONS: The nanoparticle formulations appear to have no effect on primary BBB parameters in established in vitro and in vivo blood-brain barrier models.