技术资料

The presence of persistent,latent HIV reservoirs in CD4+ T cells obstructs current efforts to cure infection. The so-called kick-and-kill paradigm proposes to purge these reservoirs by combining latency-reversing agents with immune effectors such as cytotoxic T lymphocytes. Support for this approach is largely based on success in latency models,which do not fully reflect the makeup of latent reservoirs in individuals on long-term antiretroviral therapy (ART). Recent studies have shown that CD8+ T cells have the potential to recognize defective proviruses,which comprise the vast majority of all infected cells,and that the proviral landscape can be shaped over time due to in vivo clonal expansion of infected CD4+ T cells. Here,we have shown that treating CD4+ T cells from ART-treated individuals with combinations of potent latency-reversing agents and autologous CD8+ T cells consistently reduced cell-associated HIV DNA,but failed to deplete replication-competent virus. These CD8+ T cells recognized and potently eliminated CD4+ T cells that were newly infected with autologous reservoir virus,ruling out a role for both immune escape and CD8+ T cell dysfunction. Thus,our results suggest that cells harboring replication-competent HIV possess an inherent resistance to CD8+ T cells that may need to be addressed to cure infection. View Publication

Transcriptionally activated monocytes are recruited to the heart after acute myocardial infarction (AMI). After AMI in mice and humans,the number of extracellular vesicles (EVs) increased acutely. In humans,EV number correlated closely with the extent of myocardial injury. We hypothesized that EVs mediate splenic monocyte mobilization and program transcription following AMI. Some plasma EVs bear endothelial cell (EC) integrins,and both proinflammatory stimulation of ECs and AMI significantly increased VCAM-1-positive EV release. Injected EC-EVs localized to the spleen and interacted with,and mobilized,splenic monocytes in otherwise naive,healthy animals. Analysis of human plasma EV-associated miRNA showed 12 markedly enriched miRNAs after AMI; functional enrichment analyses identified 1,869 putative mRNA targets,which regulate relevant cellular functions (e.g.,proliferation and cell movement). Furthermore,gene ontology termed positive chemotaxis as the most enriched pathway for the miRNA-mRNA targets. Among the identified EV miRNAs,EC-associated miRNA-126-3p and -5p were highly regulated after AMI. miRNA-126-3p and -5p regulate cell adhesion- and chemotaxis-associated genes,including the negative regulator of cell motility,plexin-B2. EC-EV exposure significantly downregulated plexin-B2 mRNA in monocytes and upregulated motility integrin ITGB2. These findings identify EVs as a possible novel signaling pathway by linking ischemic myocardium with monocyte mobilization and transcriptional activation following AMI. View Publication

Pulmonary disease is the major cause of morbidity and mortality in patients with cystic fibrosis,a disease caused by mutations in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. Heterogeneity in CFTR genotype-phenotype relationships in affected individuals plus the escalation of drug discovery targeting specific mutations highlights the need to develop robust in vitro platforms with which to stratify therapeutic options using relevant tissue. Toward this goal,we adapted a fluorescence plate reader assay of apical CFTR-mediated chloride conductance to enable profiling of a panel of modulators on primary nasal epithelial cultures derived from patients bearing different CFTR mutations. This platform faithfully recapitulated patient-specific responses previously observed in the gold-standard but relatively low-throughput Ussing chamber. Moreover using this approach we identified a novel strategy with which to augment the response to an approved drug in specific patients. In proof of concept studies we also validated the use of this platform in measuring drug responses in lung cultures differentiated from cystic fibrosis iPS cells. Taken together we show that this medium throughput assay of CFTR activity has the potential to stratify cystic fibrosis patient-specific responses to approved drugs and investigational compounds in vitro in primary and iPS cell-derived airway cultures. View Publication

UNLABELLED Among the known genetic risk factors for Parkinson disease,mutations in GBA1,the gene responsible for the lysosomal disorder Gaucher disease,are the most common. This genetic link has directed attention to the role of the lysosome in the pathogenesis of parkinsonism. To study how glucocerebrosidase impacts parkinsonism and to evaluate new therapeutics,we generated induced human pluripotent stem cells from four patients with Type 1 (non-neuronopathic) Gaucher disease,two with and two without parkinsonism,and one patient with Type 2 (acute neuronopathic) Gaucher disease,and differentiated them into macrophages and dopaminergic neurons. These cells exhibited decreased glucocerebrosidase activity and stored the glycolipid substrates glucosylceramide and glucosylsphingosine,demonstrating their similarity to patients with Gaucher disease. Dopaminergic neurons from patients with Type 2 and Type 1 Gaucher disease with parkinsonism had reduced dopamine storage and dopamine transporter reuptake. Levels of α-synuclein,a protein present as aggregates in Parkinson disease and related synucleinopathies,were selectively elevated in neurons from the patients with parkinsonism or Type 2 Gaucher disease. The cells were then treated with NCGC607,a small-molecule noninhibitory chaperone of glucocerebrosidase identified by high-throughput screening and medicinal chemistry structure optimization. This compound successfully chaperoned the mutant enzyme,restored glucocerebrosidase activity and protein levels,and reduced glycolipid storage in both iPSC-derived macrophages and dopaminergic neurons,indicating its potential for treating neuronopathic Gaucher disease. In addition,NCGC607 reduced α-synuclein levels in dopaminergic neurons from the patients with parkinsonism,suggesting that noninhibitory small-molecule chaperones of glucocerebrosidase may prove useful for the treatment of Parkinson disease. SIGNIFICANCE STATEMENT Because GBA1 mutations are the most common genetic risk factor for Parkinson disease,dopaminergic neurons were generated from iPSC lines derived from patients with Gaucher disease with and without parkinsonism. These cells exhibit deficient enzymatic activity,reduced lysosomal glucocerebrosidase levels,and storage of glucosylceramide and glucosylsphingosine. Lines generated from the patients with parkinsonism demonstrated elevated levels of α-synuclein. To reverse the observed phenotype,the neurons were treated with a novel noninhibitory glucocerebrosidase chaperone,which successfully restored glucocerebrosidase activity and protein levels and reduced glycolipid storage. In addition,the small-molecule chaperone reduced α-synuclein levels in dopaminergic neurons,indicating that chaperoning glucocerebrosidase to the lysosome may provide a novel therapeutic strategy for both Parkinson disease and neuronopathic forms of Gaucher disease. View Publication

Neural stem and progenitor cells (NSCs/NPCs) are distinct groups of cells found in the mammalian central nervous system (CNS). Previously we determined that members of the High Mobility Group (HMG) B family of chromatin structural proteins modulate NSC proliferation and self-renewal. Among them HMGB2 was found to be dynamically expressed in proliferating and differentiating NSCs,suggesting that it may regulate NSC maintenance. We report now that Hmgb2(-/-) mice exhibit SVZ hyperproliferation,increased numbers of SVZ NSCs,and a trend towards aberrant increases in newly born neurons in the olfactory bulb (OB) granule cell layer. Increases in the levels of the transcription factor p21 and the Neural cell adhesion molecule (NCAM),along with down-regulation of the transcription/pluripotency factor Oct4 in the Hmgb2-/- SVZ point to a possible pathway for this increased proliferation/differentiation. Our findings suggest that HMGB2 functions as a modulator of neurogenesis in young adult mice through regulation of NSC proliferation,and identify a potential target via which CNS repair could be amplified following trauma or disease-based neuronal degeneration. View Publication

INTRODUCTION Despite attempts to prevent brain injury during the hyperacute phase of stroke,most sufferers end up with significant neuronal loss and functional deficits. The use of cell-based therapies to recover the injured brain offers new hope. In the current study,we employed human neural stem cells (hNSCs) isolated from subventricular zone (SVZ),and directed their differentiation into GABAergic neurons followed by transplantation to ischemic brain. METHODS Pre-differentiated GABAergic neurons,undifferentiated SVZ-hNSCs or media alone were stereotaxically transplanted into the rat brain (n=7/group) 7 days after endothelin-1 induced stroke. Neurological outcome was assessed by neurological deficit scores and the cylinder test. Transplanted cell survival,cellular phenotype and maturation were assessed using immunohistochemistry and confocal microscopy. RESULTS Behavioral assessments revealed accelerated improvements in motor function 7 days post-transplant in rats treated with pre-differentiated GABAergic cells in comparison to media alone and undifferentiated hNSC treated groups. Histopathology 28 days-post transplant indicated that pre-differentiated cells maintained their GABAergic neuronal phenotype,showed evidence of synaptogenesis and up-regulated expression of both GABA and calcium signaling proteins associated with neurotransmission. Rats treated with pre-differentiated cells also showed increased neurogenic activity within the SVZ at 28 days,suggesting an additional trophic role of these GABAergic cells. In contrast,undifferentiated SVZ-hNSCs predominantly differentiated into GFAP-positive astrocytes and appeared to be incorporated into the glial scar. CONCLUSION Our study is the first to show enhanced exogenous repopulation of a neuronal phenotype after stroke using techniques aimed at GABAergic cell induction prior to delivery that resulted in accelerated and improved functional recovery. View Publication

The adaptive immune response involves T cell differentiation and migration to sites of inflammation. T cell trafficking is initiated by rolling on inflamed endothelium. Tethers and slings,discovered in neutrophils,facilitate cell rolling at high shear stress. Here,we demonstrate that the ability to form tethers and slings during rolling is highly inducible in T helper 1 (Th1),Th17,and regulatory T (Treg) cells but less in Th2 cells. In vivo,endogenous Treg cells rolled stably in cremaster venules at physiological shear stress. Quantitative dynamic footprinting nanoscopy of Th1,Th17,and Treg cells uncovered the formation of multiple tethers per cell. Human Th1 cells also showed tethers and slings. RNA sequencing (RNA-seq) revealed the induction of cell migration and cytoskeletal genes in sling-forming cells. We conclude that differentiated CD4 T cells stabilize rolling by inducible tether and sling formation. These phenotypic changes approximate the adhesion phenotype of neutrophils and support CD4 T cell access to sites of inflammation. View Publication

Efficient gene transfer into human hematopoietic stem cells (HSCs) is an important goal in the study of the hematopoietic system as well as for gene therapy of hematopoietic disorders. A lentiviral vector based on the human immunodeficiency virus (HIV) was able to transduce human CD34+ cells capable of stable,long-term reconstitution of nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. High-efficiency transduction occurred in the absence of cytokine stimulation and resulted in transgene expression in multiple lineages of human hematopoietic cells for up to 22 weeks after transplantation. View Publication

Cytokines produced by antigen-presenting cells are known to affect the development and cytokine profile of T cells. The immune response modifiers imiquimod and R-848 were previously shown to stimulate human and mouse cultures to secrete interferon-alpha. Results from the present study demonstrate that R-848 and imiquimod are capable of inducing interleukin-12 and interferon-gamma in mouse and human cell cultures. Both CD4(+) and CD8(+) T lymphocytes were responsible for producing IFN-gamma following stimulation with R-848. Macrophages were required for induction of interferon-gamma by R-848 and the cytokines IFN-alpha and IL-12 mediated this response. R-848 and imiquimod were also found to inhibit IL-4 and IL-5 production in mouse and human culture systems. The inhibition of IL-5 in response to R-848 is seen in cultures containing CD4(+) lymphocytes and macrophages and is mediated in part by IFN-alpha. These data suggest that imiquimod and R-848 may have clinical utility in diseases where cell-mediated immune responses are important and in diseases associated with overexpression of IL-4 or IL-5 such as atopic disease. View Publication

In the adult human,mesenchymal stem cells (MSCs) resident in bone marrow retain the capacity to proliferate and differentiate along multiple connective tissue lineages,including cartilage. In this study,culture-expanded human MSCs (hMSCs) of 60 human donors were induced to express the morphology and gene products of chondrocytes. Chondrogenesis was induced by culturing hMSCs in micromass pellets in the presence of a defined medium that included 100 nM dexamethasone and 10 ng/ml transforming growth factor-beta(3) (TGF-beta(3)). Within 14 days,cells secreted an extracellular matrix incorporating type II collagen,aggrecan,and anionic proteoglycans. hMSCs could be further differentiated to the hypertrophic state by the addition of 50 nM thyroxine,the withdrawal of TGF-beta(3),and the reduction of dexamethasone concentration to 1 nM. Increased understanding of the induction of chondrogenic differentiation should lead to further progress in defining the mechanisms responsible for the generation of cartilaginous tissues,their maintenance,and their regeneration. View Publication

SU5416,a novel synthetic compound,is a potent and selective inhibitor of the Flk-1/KDR receptor tyrosine kinase that is presently under evaluation in Phase I clinical studies for the treatment of human cancers. SU5416 was shown to inhibit vascular endothelial growth factor-dependent mitogenesis of human endothelial cells without inhibiting the growth of a variety of tumor cells in vitro. In contrast,systemic administration of SU5416 at nontoxic doses in mice resulted in inhibition of subcutaneous tumor growth of cells derived from various tissue origins. The antitumor effect of SU5416 was accompanied by the appearance of pale white tumors that were resected from drug-treated animals,supporting the antiangiogenic property of this agent. These findings support that pharmacological inhibition of the enzymatic activity of the vascular endothelial growth factor receptor represents a novel strategy for limiting the growth of a wide variety of tumor types. View Publication

Mitogen-activated protein (MAP) kinases are serine/threonine kinases that mediate intracellular signal transduction pathways. Pyridinyl imidazole compounds block pro-inflammatory cytokine production and are specific p38 kinase inhibitors. ERK2 is related to p38 in sequence and structure,but is not inhibited by pyridinyl imidazole inhibitors. Crystal structures of two pyridinyl imidazoles complexed with p38 revealed these compounds bind in the ATP site. Mutagenesis data suggested a single residue difference at threonine 106 between p38 and other MAP kinases is sufficient to confer selectivity of pyridinyl imidazoles. We have changed the equivalent residue in human ERK2,Q105,into threonine and alanine,and substituted four additional ATP binding site residues. The single residue change Q105A in ERK2 enhances the binding of SB202190 at least 25,000-fold compared to wild-type ERK2. We report enzymatic analyses of wild-type ERK2 and the mutant proteins,and the crystal structure of a pyridinyl imidazole,SB203580,bound to an ERK2 pentamutant,I103L,Q105T,D106H,E109G. T110A. These ATP binding site substitutions induce low nanomolar sensitivity to pyridinyl imidazoles. Furthermore,we identified 5-iodotubercidin as a potent ERK2 inhibitor,which may help reveal the role of ERK2 in cell proliferation. View Publication