Contribution of neural crest-derived cells in the embryonic and adult thymus

Abstract Neural crest (NC)-derived mesenchyme has previously been shown to play an important role in the development of fetal thymus. Using Wnt1-Cre and Sox10-Cre mice crossed to Rosa26eYfp reporter mice, we have revealed NC-derived mesenchymal cells in the adult murine thymus. We report that NC-derived cells infiltrate the thymus before day 13.5 of embryonic development (E13.5) and differentiate into cells with characteristics of smooth muscle cells associated with large vessels, and pericytes associated with capillaries. In the adult organ at 3 mo of age, these NC-derived perivascular cells continue to be associated with the vasculature, providing structural support to the blood vessels and possibly regulating endothelial cell function.</jats:p

Position effect variegation and imprinting of transgenes in lymphocytes

Sequences proximal to transgene integration sites are able to deregulate transgene expression resulting in complex position effect phenotypes. In addition, transgenes integrated as repeated arrays are susceptible to repeat-induced gene silencing. Using a Cre recombinase-based system we have addressed the influence of transgene copy number (CN) on expression of hCD2 transgenes. CN reduction resulted in a decrease, increase or no effect on variegation depending upon the site of integration. This finding argues that repeat-induced gene silencing is not the principle cause of hCD2 transgene variegation. These results also suggest that having more transgene copies can be beneficial at some integration sites. The transgenic lines examined in this report also exhibited a form of imprinting, which was manifested by decreased levels of expression and increased levels of variegation, upon maternal transmission; and this correlated with DNA hypermethylation and a reduction in epigenetic chromatin modifications normally associated with active genes

A comparative study of the actions of alkylpyridinium salts from a marine sponge and related synthetic compounds in rat cultured hippocampal neurones

BACKGROUND: Polymeric alkylpyridinium salts (poly-APS), are chemical defences produced by marine sponges including Reniera sarai. Poly-APS have previously been shown to effectively deliver macromolecules into cells. The efficiency of this closely follows the ability of poly-APS to form transient pores in membranes, providing strong support for a pore-based delivery mechanism. Recently, water soluble compounds have been synthesised that are structurally related to the natural polymers but bear a different number of pyridinium units. These compounds may share a number of bio-activities with poly-APS. Using electrophysiology, calcium imaging and 1,6-diphenyl-1,3,5-hexatriene imaging, the pore forming properties of poly-APS and four related synthetic oligomers have been tested on primary cultured rat hippocampal neurones. RESULTS: Acute application of poly-APS (0.5 μg/ml), reduced membrane potential, input resistance and suppressed action potential firing. Poly-APS evoked inward cation currents with linear current-voltage relationships similar to actions of pore formers on other cell types. Poly-APS (0.005–5 μg/ml) also produced Ca(2+ )transients in ~41% of neurones. The dose-dependence of poly-APS actions were complex, such that at 0.05 μg/ml and 5 μg/ml poly-APS produced varying magnitudes of membrane permeability depending on the order of application. Data from surface plasmon resonance analysis suggested accumulation of poly-APS in membranes and subsequent enhanced poly-APS binding. Even at 10–100 fold higher concentrations, none of the synthetic compounds produced changes in electrophysiological characteristics of the same magnitude as poly-APS. Of the synthetic oligomers tested compounds 1 (monomeric) and tetrameric 4 (5–50 μg/ml) induced small transient currents and 3 (trimeric) and 4 (tetrameric) produced significant Ca(2+ )transients in hippocampal neurones. CONCLUSION: Poly-APS induced pore formation in hippocampal neurones and such pores were transient, with neurones recovering from exposure to these polymers. Synthetic structurally related oligomers were not potent pore formers when compared to poly-APS and affected a smaller percentage of the hippocampal neurone population. Poly-APS may have potential as agents for macromolecular delivery into CNS neurones however; the smaller synthetic oligomers tested in this study show little potential for such use. This comparative analysis indicated that the level of polymerisation giving rise to the supermolecular structure in the natural compounds, is likely to be responsible for the activity here reported

A comparative study of the actions of alkylpyridinium salts from a marine sponge and related synthetic compounds in rat cultured hippocampal neurones

Background: Polymeric alkylpyridinium salts (poly-APS), are chemical defences produced by marine sponges including Reniera sarai. Poly-APS have previously been shown to effectively deliver macromolecules into cells. The efficiency of this closely follows the ability of poly-APS to form transient pores in membranes, providing strong support for a pore-based delivery mechanism. Recently, water soluble compounds have been synthesised that are structurally related to the natural polymers but bear a different number of pyridinium units. These compounds may share a number of bio-activities with poly-APS. Using electrophysiology, calcium imaging and 1,6-diphenyl-1,3,5-hexatriene imaging, the pore forming properties of poly-APS and four related synthetic oligomers have been tested on primary cultured rat hippocampal neurones.Results: Acute application of poly-APS (0.5 μg/ml), reduced membrane potential, input resistance and suppressed action potential firing. Poly-APS evoked inward cation currents with linear current-voltage relationships similar to actions of pore formers on other cell types. Poly-APS (0.005-5 μg/ml) also produced Ca2+ transients in ∼41% of neurones. The dose-dependence of poly-APS actions were complex, such that at 0.05 μg/ml and 5 μg/ml poly-APS produced varying magnitudes of membrane permeability depending on the order of application. Data from surface plasmon resonance analysis suggested accumulation of poly-APS in membranes and subsequent enhanced poly-APS binding. Even at 10-100 fold higher concentrations, none of the synthetic compounds produced changes in electrophysiological characteristics of the same magnitude as poly-APS. Of the synthetic oligomers tested compounds 1 (monomeric) and tetrameric 4 (5-50 μg/ ml) induced small transient currents and 3 (trimeric) and 4 (tetrameric) produced significant Ca2+ transients in hippocampal neurones.Conclusion: Poly-APS induced pore formation in hippocampal neurones andsuch pores were transient, with neurones recovering from exposure to these polymers. Synthetic structurally related oligomers were not potent pore formers when compared to poly-APS and affected a smaller percentage of the hippocampal neurone population. Poly-APS may have potential as agents for macromolecular delivery into CNS neurones however; the smaller synthetic oligomers tested in this study show little potential for such use. This comparative analysis indicated that the level of polymerisation giving rise to the supermolecular structure in the natural compounds, is likely to be responsible for the activity here reported.</p

Effective bridging therapy can improve CD19 CAR-T outcomes while maintaining safety in patients with large B-cell lymphoma

The impact of bridging therapy (BT) on CD19-directed chimeric antigen receptor T-cell (CD19CAR-T) outcomes in large B-cell lymphoma (LBCL) is poorly characterised. Current practice is guided by physician preference rather than established evidence. Identification of effective BT modalities and factors predictive of response could improve CAR-T intention to treat and clinical outcomes. We assessed BT modality and response in 375 adult LBCL patients in relation to outcomes following axicabtagene ciloleucel (Axi-cel) or tisagenlecleucel (Tisa-cel). The majority of patients received BT with chemotherapy (57%) or radiotherapy (17%). We observed that BT was safe for patients, with minimal morbidity/mortality. We showed that complete or partial response to BT conferred a 42% reduction in disease progression and death following CD19CAR-T therapy. Multivariate analysis identified several factors associated with likelihood of response to BT, including response to last line therapy, the absence of bulky disease, and the use of Polatuzumab-containing chemotherapy regimens. Our data suggested that complete/partial response to BT may be more important for Tisa-cel than Axi-cel, as all Tisa-cel patients with less than partial response to BT experienced frank relapse within 12 months of CD19CAR-T infusion. In summary, BT in LBCL should be carefully planned towards optimal response and disease debulking, to improve CD19CAR-T patient outcomes. Polatuzumab-containing regimens should be strongly considered for all suitable patients, and failure to achieve complete/partial response to BT pre-Tisa-cel may prompt consideration of further lines of BT where possible

Transcriptomics identified a critical role for Th2 cell-intrinsic miR-155 in mediating allergy and antihelminth immunity

Allergic diseases, orchestrated by hyperactive CD4^(+) Th2 cells, are some of the most common global chronic diseases. Therapeutic intervention relies upon broad-scale corticosteroids with indiscriminate impact. To identify targets in pathogenic Th2 cells, we took a comprehensive approach to identify the microRNA (miRNA) and mRNA transcriptome of highly purified cytokine-expressing Th1, Th2, Th9, Th17, and Treg cells both generated in vitro and isolated ex vivo from allergy, infection, and autoimmune disease models. We report here that distinct regulatory miRNA networks operate to regulate Th2 cells in house dust mite-allergic or helminth-infected animals and in vitro Th2 cells, which are distinguishable from other T cells. We validated several miRNA (miR) candidates (miR-15a, miR-20b, miR-146a, miR-155, and miR-200c), which targeted a suite of dynamically regulated genes in Th2 cells. Through in-depth studies using miR-155^(−/−) or miR-146a^(−/−) T cells, we identified that T-cell–intrinsic miR-155 was required for type-2 immunity, in part through regulation of S1pr1, whereas T-cell–intrinsic miR-146a was required to prevent overt Th1/Th17 skewing. These data identify miR-155, but not miR-146a, as a potential therapeutic target to alleviate Th2-medited inflammation and allergy

White Matter Hyperintensities in Vascular Contributions to Cognitive Impairment and Dementia (VCID): Knowledge Gaps and Opportunities

White matter hyperintensities (WMHs) are frequently seen on brain magnetic resonance imaging scans of older people. Usually interpreted clinically as a surrogate for cerebral small vessel disease, WMHs are associated with increased likelihood of cognitive impairment and dementia (including Alzheimer\u27s disease [AD]). WMHs are also seen in cognitively healthy people. In this collaboration of academic, clinical, and pharmaceutical industry perspectives, we identify outstanding questions about WMHs and their relation to cognition, dementia, and AD. What molecular and cellular changes underlie WMHs? What are the neuropathological correlates of WMHs? To what extent are demyelination and inflammation present? Is it helpful to subdivide into periventricular and subcortical WMHs? What do WMHs signify in people diagnosed with AD? What are the risk factors for developing WMHs? What preventive and therapeutic strategies target WMHs? Answering these questions will improve prevention and treatment of WMHs and dementia

Genome-wide meta-analysis identifies genetic variants associated with glycemic response to sulfonylureas

OBJECTIVE: Sulfonylureas, the first available drugs for the management of type 2 diabetes, remain widely prescribed today. However, there exists significant variability in glycemic response to treatment. We aimed to establish heritability of sulfonylurea response and identify genetic variants and interacting treatments associated with HbA(1c) reduction. RESEARCH DESIGN AND METHODS: As an initiative of the Metformin Genetics Plus Consortium (MetGen Plus) and the DIabetes REsearCh on patient straTification (DIRECT) consortium, 5,485 White Europeans with type 2 diabetes treated with sulfonylureas were recruited from six referral centers in Europe and North America. We first estimated heritability using the generalized restricted maximum likelihood approach and then undertook genome-wide association studies of glycemic response to sulfonylureas measured as HbA(1c) reduction after 12 months of therapy followed by meta-analysis. These results were supported by acute glipizide challenge in humans who were naïve to type 2 diabetes medications, cis expression quantitative trait loci (eQTL), and functional validation in cellular models. Finally, we examined for possible drug-drug-gene interactions. RESULTS: After establishing that sulfonylurea response is heritable (mean ± SEM 37 ± 11%), we identified two independent loci near the GXYLT1 and SLCO1B1 genes associated with HbA(1c) reduction at a genome-wide scale (P < 5 × 10(−8)). The C allele at rs1234032, near GXYLT1, was associated with 0.14% (1.5 mmol/mol), P = 2.39 × 10(−8)), lower reduction in HbA(1c). Similarly, the C allele was associated with higher glucose trough levels (β = 1.61, P = 0.005) in healthy volunteers in the SUGAR-MGH given glipizide (N = 857). In 3,029 human whole blood samples, the C allele is a cis eQTL for increased expression of GXYLT1 (β = 0.21, P = 2.04 × 10(−58)). The C allele of rs10770791, in an intronic region of SLCO1B1, was associated with 0.11% (1.2 mmol/mol) greater reduction in HbA(1c) (P = 4.80 × 10(−8)). In 1,183 human liver samples, the C allele at rs10770791 is a cis eQTL for reduced SLCO1B1 expression (P = 1.61 × 10(−7)), which, together with functional studies in cells expressing SLCO1B1, supports a key role for hepatic SLCO1B1 (encoding OATP1B1) in regulation of sulfonylurea transport. Further, a significant interaction between statin use and SLCO1B1 genotype was observed (P = 0.001). In statin nonusers, C allele homozygotes at rs10770791 had a large absolute reduction in HbA(1c) (0.48 ± 0.12% [5.2 ± 1.26 mmol/mol]), equivalent to that associated with initiation of a dipeptidyl peptidase 4 inhibitor. CONCLUSIONS: We have identified clinically important genetic effects at genome-wide levels of significance, and important drug-drug-gene interactions, which include commonly prescribed statins. With increasing availability of genetic data embedded in clinical records these findings will be important in prescribing glucose-lowering drugs