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Connolly, C.

Publications and source records attributed to Connolly, C..

8 recordsLinked to original sources

Cannabinoid CB2 receptor activation drives glucose uptake, shifting T cell metabolism.

Cannabinoid receptor 2 (CB2R) is highly expressed on immune cells, but its role in T cell metabolism remains unclear. Here, we show that CB2R activation rapidly increases glucose uptake in human Jurkat T cells and drives a broader metabolic reprogramming away from glycolysis toward oxidative metabolism and the pentose phosphate pathway. Pharmacological CB2R activation increased mitochondrial mass, spare respiratory capacity, proton leak, and NADPH production, while CB2R inverse agonism produced the opposite effects. These metabolic changes were accompanied by upregulation of key pentose phosphate pathway enzymes, including GALT and TALDO1, and were abolished in CNR2-deficient cells, confirming receptor dependence. In primary human lamina propria mononuclear cells, CB2R signalling also influenced memory and gut-homing-associated T cell phenotypes, including integrin 4{beta}7 expression. Together, these findings identify CB2R as a regulator of T cell bioenergetics and suggest that cannabinoid signalling may promote metabolic states linked to memory and tissue-homing functions in chronic intestinal inflammation. Brief SummaryO_LICB2R agonist-mediated increased glucose uptake in human T cells is lost in CNR2-deficient cells, suggesting that the response is receptor-dependent. C_LIO_LICB2R activation rewires T-cell metabolism toward increased oxidative phosphorylation, spare respiratory capacity, mitochondrial mass, and pentose phosphate pathway metabolism, including higher NADPH and PPP-enzyme expression. C_LIO_LIIn primary human intestinal immune cells, CB2R also promotes gut-homing and memory-associated T-cell phenotypes, including 4{beta}7 and CD103 integrin induction ex vivo, suggesting a possible link to exacerbation of chronic intestinal inflammation. C_LI

immunology↗

Remodelling of supernumerary leaflet primordia leads to bicuspid aortic valve (BAV) caused by loss of primary cilia

AimsBicuspid aortic valve (BAV), where two valve leaflets are found instead of the usual three, affects 1-2% of the general population and is associated with significant morbidity and mortality. Despite its frequency, the majority of cases remain unexplained. This is, at least in part, because there are two types of valve leaflet primordia: endocardial cushions and intercalated valve swellings (ICVS). Moreover, multiple progenitors make distinct contribution to the formation of these primordia. Genomic studies in mouse and human have suggested a correlation between BAV and malfunctional primary cilia. However, the precise requirement for cilia during early embryonic valvulogenesis remains unknown. Methods and resultsHere, we disrupted primary cilia by deleting the ciliary gene Ift88 in the main progenitor cells forming the aortic valve using specific Cre drivers: Wnt1-Cre for neural crest cells, Isl1-Cre for second heart field cells (SHF); Tie2-Cre for endocardial-derived cells and Tnnt2-Cre for direct-differentiating SHF in the ICVS. Loss of Ift88, and thus primary cilia, from neural crest cells and endocardium did not impact aortic valve formation. However, primary cilia are essential in SHF cells for aortic valve leaflet formation, with over half of Ift88f/f;Isl1-Cre mutants presenting with BAV. As the valve leaflets are forming, 50% of the Ift88f/f;Isl1-Cre mutants have two small leaflets in the position of the usual posterior leaflet, meaning that at this stage the aortic valve is quadricuspid, which then remodels to BAV by E15.5. Mechanistic studies demonstrate premature differentiation of SHF cells as the ICVS form, leading to the formation of a broadened ICVS that forms two posterior leaflet precursors. This abnormality in the formation of the ICVS is associated with disruption of Notch-Jag1 signalling pathway, with Jag1f/f;Isl1-Cre mutants presenting with a similar phenotype. ConclusionsThese data show that primary cilia, via the Notch-Jag1 signalling pathway, regulate differentiation of SHF cells in the aortic valve primordia. Additionally, we identify a mechanistic link between the developmental basis of quadricuspid and bicuspid arterial valve leaflets. Translational PerspectiveSeveral genomic studies in human and mouse have suggested that disruption of cilia-related genes may be a significant cause of CHD. Although there is limited data from animal models to suggest a link between cilia and bicuspid aortic valve (BAV), the mechanisms underpinning BAV formation during early valvulogenesis have not been described. Here, we established a potential mechanism underpinning BAV formation, highlighting a role for primary cilia in a subset of valve interstitial cells (VIC) derived from second heart field progenitors. Loss of cilia altered VIC differentiation and valvulogenesis. This study confirms that disruption of cilial formation and/or function can lead to arterial valve defects and could pave the way to finding therapies for patient benefit.

developmental biology↗

An efficient and adaptable workflow for editing disease-relevant single nucleotide variants using CRISPR/Cas9

Single nucleotide variants are the commonest genetic alterations in the human genome. At least 60,000 have been reported to be associated with disease. The CRISPR/Cas9 system has transformed genetic research, making it possible to edit single nucleotides and study the function of genetic variants in vitro. While significant advances have improved the efficiency of CRISPR/Cas9, the editing of single nucleotides remains challenging. There are two major obstacles: low efficiency of accurate editing and the isolation of these cells from a pool of cells with other editing outcomes. We present data from 85 transfections of induced pluripotent stem cells and an immortalised cell line, comparing the effects of altering CRISPR/Cas9 design and experimental conditions on rates of single nucleotide substitution. We targeted variants in TP53, which predispose to several cancers, and in TBXT which is implicated in the pathogenesis of the bone cancer, chordoma. We describe a scalable and adaptable workflow for single nucleotide editing that incorporates contemporary techniques including Illumina MiSeq sequencing, TaqMan qPCR and digital droplet PCR for screening transfected cells as well as quality control steps to mitigate against common pitfalls. This workflow can be applied to CRISPR/Cas9 and other genome editing systems to maximise experimental efficiency. Simple SummaryCRISPR/Cas9 has revolutionised genetic research. Cas9 generates a double strand break with high efficiency which is repaired by a cells pathways. If a genetic template is provided, the damage can be accurately repaired to introduce a desired genetic alteration. However, accurate repair occurs at a low efficiency and in a small proportion of edited cells, representing the main obstacles in harnessing CRISPRs full potential. Using data from 85 CRISPR experiments for single nucleotide editing, targeting three locations in the human genome that are implicated in predisposition to cancer, we report the effect of different experimental conditions on editing efficiency. We describe current technologies that can be used to streamline the identification of accurately edited cells and synthesise these into an adaptable workflow that can be applied to CRISPR/Cas9 experiments to achieve single nucleotide editing in disease-relevant cell models.

molecular biology↗

SAF-A promotes origin licensing and replication fork progression to ensure robust DNA replication

The organisation of chromatin is closely intertwined with biological activities of chromosome domains, including transcription and DNA replication status. Scaffold attachment factor A (SAF-A), also known as Heteronuclear Ribonucleoprotein Protein U (HNRNPU), contributes to the formation of open chromatin structure. Here we demonstrate that SAF-A promotes the normal progression of DNA replication, and enables resumption of replication after inhibition. We report that cells depleted for SAF-A show reduced origin licensing in G1 phase, and consequently reduced origin activation frequency in S phase. Replication forks progress slowly in cells depleted for SAF-A, also contributing to reduced DNA synthesis rate. Single-cell replication timing analysis revealed that the boundaries between early- and late-replicating domains are blurred in cells depleted for SAF-A. Associated with these defects, SAF-A-depleted cells show elevated {gamma}H2A phosphorylation and tend to enter quiescence. Overall we find that SAF-A protein promotes robust DNA replication to ensure continuing cell proliferation.

cell biology↗

N-acetyltransferase 2 genotypes amongst ulu Speaking South Africans and isoniazid / N-acetyl-isoniazid pharmacokinetics during ant-tuberculosis treatment

BackgroundDistribution of N-acetyltransferase2 (NAT2) polymorphisms varies considerably among different ethnic groups. Information on NAT2 single-nucleotide polymorphisms in South African population is limited. We investigated NAT2 polymorphisms and their effect on isoniazid pharmacokinetics in Zulu black HIV-infected South Africans in Durban, South Africa. Methods: HIV-infected participants with culture-confirmed pulmonary tuberculosis (TB) were enrolled from two unrelated studies. Culture-confirmed participants were genotyped for NAT2 polymorphisms 282C>T, 341T>C, 481C>T, 857G>A, 590G>A and 803A>G using Life Technologies pre-validated Taqman assays (Life Technologies, Paisley, UK). Participants underwent sampling for determination of plasma isoniazid and N-acetylisoniazid concentrations. ResultsAmongst the 120 patients, 63/120 (52.5%) were slow metabolisers (NAT2*5/*5), 43/120 (35.8%) had intermediate (NAT2*5/12), and 12/120 (11.7%) had rapid genotype (NAT2*4/*11, NAT2*11/12 and NAT2*12/12). NAT2 alleles in this study were *4, *5C, *5D, *5E, *5J, *5K, *5KA, *5T, *11A, *12A/12C and *12M. NAT2*5 was the most frequent allele (70.4%) followed by NAT2*12 (27.9%). 34/40 had both PK results and NAT2 genotyping results. The median area under the concentration-time-curve to infinity (AUC0-{infty}) interquartile range (IQR) was 7.81 (5.87 - 16.83) g/ml/hr and maximum concentration (Cmax) 3.14 g/ml (2.42 - 4.36) g/mL. Individual polymorphisms were not equally distributed, with some represented in small numbers. Genotype did not correlate with phenotype, rapid genotype showing higher AUC0-{infty} than slow but not significant, p=0.43. ConclusionThere was high prevalence of slow followed by intermediate then rapid acetylator genotypes. The poor concordance between genotype and phenotype suggests that other factors or genetic loci influence INH metabolism, and warrants further investigation in this population.

genetics↗

A tree-planting decision support tool for urban heat island mitigation

Heat poses an urgent threat to public health in cities, as the urban heat island (UHI) effect can amplify exposures, contributing to high heat-related mortality and morbidity. Urban trees have the potential to mitigate by providing substantial cooling, as well as co-benefits such as reductions in energy consumption. The City of Boston has attempted to expand its urban canopy, yet maintenance costs and high tree mortality have hindered successful canopy expansion. Here, we present an interactive web application called "Right Place, Right Tree - Boston" that aims to support informed decision-making for planting new trees. To highlight priority regions for canopy expansion, we developed a Boston-specific Heat Vulnerability Index (HVI) and present this alongside maps of summer temperatures. We also provide information about tree pests and diseases, suitability of species for various conditions, land ownership, maintenance tips, and alternatives to tree planting.

scientific communication and education↗

Brain Aging in Major Depressive Disorder: Results from the ENIGMA Major Depressive Disorder working group

BackgroundMajor depressive disorder (MDD) is associated with an increased risk of brain atrophy, aging-related diseases, and mortality. We examined potential advanced brain aging in MDD patients, and whether this process is associated with clinical characteristics in a large multi-center international dataset. MethodsWe performed a mega-analysis by pooling brain measures derived from T1-weighted MRI scans from 29 samples worldwide. Normative brain aging was estimated by predicting chronological age (10-75 years) from 7 subcortical volumes, 34 cortical thickness and 34 surface area, lateral ventricles and total intracranial volume measures separately in 1,147 male and 1,386 female controls from the ENIGMA MDD working group. The learned model parameters were applied to 1,089 male controls and 1,167 depressed males, and 1,326 female controls and 2,044 depressed females to obtain independent unbiased brain-based age predictions. The difference between predicted "brain age" and chronological age was calculated to indicate brain predicted age difference (brain-PAD). FindingsOn average, MDD patients showed a higher brain-PAD of +0.90 (SE 0.21) years (Cohens d=0.12, 95% CI 0.06-0.17) compared to controls. Relative to controls, first-episode and currently depressed patients showed higher brain-PAD (+1.2 [0.3] years), and the largest effect was observed in those with late-onset depression (+1.7 [0.7] years). In addition, higher brain-PAD was associated with higher self-reported depressive symptomatology (b=0.05, p=0.004). InterpretationThis highly powered collaborative effort showed subtle patterns of abnormal structural brain aging in MDD. Substantial within-group variance and overlap between groups were observed. Longitudinal studies of MDD and somatic health outcomes are needed to further assess the predictive value of these brain-PAD estimates. FundingThis work was supported, in part, by NIH grants U54 EB020403 and R01 MH116147.

neuroscience↗

Type-2 CD8+ T lymphocytes responsive to PGD2 and LTE4 in severe eosinophilic asthma

The functions and in vivo roles of type-2 CD8+ T cells in humans have not been well defined and this cell type has been largely overlooked in models of disease. We investigated this in the context of severe asthma with persistent airway eosinophilia - a phenotype associated with high exacerbation risk and responsiveness to type-2 cytokine-targeted therapies. In two independent cohorts we show that, in contrast to Th2 cells, type-2 cytokine-secreting CD8+CRTH2+ (Tc2) cells are enriched in blood and airways in severe eosinophilic asthma. Concentrations of prostaglandin D2 (PGD2) and cysteinyl leukotriene E4 (LTE4) are also increased in the airways of the same group of patients. In vitro PGD2 and LTE4 function synergistically to trigger Tc2 cell recruitment and activation in a TCR-independent manner. These lipids regulate diverse genes in Tc2 cells inducing type-2 cytokines and many other pro-inflammatory cytokines and chemokines which could contribute to eosinophilia. These findings are consistent with an important innate-like role for human Tc2 cells in severe eosinophilic asthma and suggest a potential target for therapeutic intervention in this and other diseases.

immunology↗