👤 Martin Noble

Chikungunya virus (CHIKV), a mosquito-borne alphavirus, causes significant global morbidity, including fever, rash, and persistent arthralgia. Utilizing untargeted lipidomics, we investigated how CHIKV infection alters host cell lipid metabolism in Vero cells. CHIKV infection induced marked catabolism of hexosylceramides, reducing their levels while increasing ceramide byproducts. Functional studies revealed a reliance on fatty acid synthesis, β-oxidation, and glycosphingolipid biosynthesis. Notably, inhibition of uridine diphosphate glycosyltransferase 8 (UGT8), essential for galactosylceramide production, significantly impaired CHIKV replication and entry in Vero cells. Sensitivity of CHIKV to UGT8 inhibition was reproduced in a disease-relevant cell line, mouse hepatocytes (Hepa1-6). CHIKV was also sensitive to evacetrapib, a cholesterol ester transfer protein (CETP) inhibitor, though the mechanism of inhibition appeared independent of CETP itself, suggesting an off-target effect. These findings highlight specific lipid pathways, particularly glycosphingolipid metabolism, as critical for CHIKV replication and further refine our understanding of how CHIKV exploits host lipid networks. This study provides new insights into CHIKV biology and suggests that targeted investigation of host lipid pathways may inform future therapeutic strategies. Show less

The PRO-CTCAE provides patient-reported data on symptomatic AEs. A summary metric-the ACS-reflecting total AE burden can be calculated by averaging AE-level composite scores at a given timepoint for each participant. This study investigated the psychometric properties and interpretability of this PRO-CTCAE ACS in patients with breast, lung, or head/neck cancers. We conducted a secondary analysis of a PRO-CTCAE validation dataset comprising 940 adults undergoing chemotherapy or radiation therapy (clinicaltrials.gov: NCT02158637). We focused on empirically recommended symptom terms for three cancer sites. Analyses included Spearman's correlations, coefficient alpha, and eigenvalues from the correlation matrices, confirmatory factor analysis (CFA), and principal component analysis (PCA). Latent profile analysis (LPA) was used to assess ACS interpretability in the lung cohort. Mean composite score inter-correlations were moderate (0.30-0.35), and coefficient alphas were high (0.81-0.91). Eigenvalue ratios and CFA supported retention of a single factor/component, with suitable model fit indices. ACS correlated highly with factor scores and the first principal component from the PCA. Reduced sets of terms produced reliable scores that closely approximated the full set scores and aligned with external criteria. LPA in the lung subgroup identified four latent classes; ACS differentiated high vs. low symptom burden groups but did not distinguish the two groups expressing distinct symptom profiles. The ACS demonstrated structural validity through adequately fitting linear factor models and effectively summarized symptomatic AE burden. However, similar ACS values may mask clinically distinct symptomatic AE profiles, underscoring the value of both summary metrics and profile-based approaches. Show less

Deregulation of the cyclin-dependent kinases (CDKs) has been implicated in the pathogenesis of multiple cancer types. Consequently, CDKs have garnered intense interest as therapeutic targets for the treatment of cancer. We describe herein the molecular and cellular effects of CCT068127, a novel inhibitor of CDK2 and CDK9. Optimized from the purine template of seliciclib, CCT068127 exhibits greater potency and selectivity against purified CDK2 and CDK9 and superior antiproliferative activity against human colon cancer and melanoma cell lines. X-ray crystallography studies reveal that hydrogen bonding with the DFG motif of CDK2 is the likely mechanism of greater enzymatic potency. Commensurate with inhibition of CDK activity, CCT068127 treatment results in decreased retinoblastoma protein (RB) phosphorylation, reduced phosphorylation of RNA polymerase II, and induction of cell cycle arrest and apoptosis. The transcriptional signature of CCT068127 shows greatest similarity to other small-molecule CDK and also HDAC inhibitors. CCT068127 caused a dramatic loss in expression of DUSP6 phosphatase, alongside elevated ERK phosphorylation and activation of MAPK pathway target genes. MCL1 protein levels are rapidly decreased by CCT068127 treatment and this associates with synergistic antiproliferative activity after combined treatment with CCT068127 and ABT263, a BCL2 family inhibitor. These findings support the rational combination of this series of CDK2/9 inhibitors and BCL2 family inhibitors for the treatment of human cancer. Show less

The BioID method uses a promiscuous biotin ligase to detect protein-protein associations as well as proximate proteins in living cells. Here we report improvements to the BioID method centered on BioID2, a substantially smaller promiscuous biotin ligase. BioID2 enables more-selective targeting of fusion proteins, requires less biotin supplementation, and exhibits enhanced labeling of proximate proteins. Thus BioID2 improves the efficiency of screening for protein-protein associations. We also demonstrate that the biotinylation range of BioID2 can be considerably modulated using flexible linkers, thus enabling application-specific adjustment of the biotin-labeling radius. Show less

Microvascular rarefaction increases vascular resistance and pressure in systemic arteries and is a hallmark of fixed essential hypertension. Preventing rarefaction by activation of angiogenic processes could lower blood pressure. Endothelial tip cells in angiogenic sprouts direct branching of microvascular networks; the process is regulated by microRNAs, particularly the miR-30 family. We investigated the contribution of miR-30 family members in arteriolar branching morphogenesis via delta-like 4 (Dll4)-Notch signaling in a zebrafish model. The miR-30 family consists of 5 members (miR-30a-e). Loss-of-function experiments showed that only miR-30a reduced growth of intersegmental arterioles involving impaired tip cell function. Overexpression of miR-30a stimulated tip cell behavior resulting in augmented branching of intersegmental arterioles. In vitro and in vivo reporter assays showed that miR-30a directly targets the Notch ligand Dll4, a key inhibitor of tip cell formation. Coadministration of a Dll4 targeting morpholino in miR-30a morphants rescued the branching defects. Conversely, conditional overexpression of Notch intracellular domain restored arteriolar branching in miR-30a gain-of-function embryos. In human endothelial cells, loss of miR-30a increased DLL4 protein levels, activated Notch signaling as indicated in Notch reporter assays, and augmented Notch downstream effector, HEY2 and EFNB2 (ephrin-B2), expression. In spheroid assays, miR-30a loss- and gain-of-function affected tip cell behavior, consistent with miR-30a targeting Dll4. Our data suggest that miR-30a stimulates arteriolar branching by downregulating endothelial Dll4 expression, thereby controlling endothelial tip cell behavior. These findings could have relevance to the rarefaction process and, therefore, to hypertension. Show less

Dysfunctions affecting the connections of basal ganglia lead to major neurological and psychiatric disorders. We investigated levels of mRNA for three neurexins (Nrxn) and three neuroligins (Nlgn) in the globus pallidus, subthalamic nucleus, and substantia nigra, in control conditions and after short-term exposure to cocaine. The expression of Nrxn2beta and Nlgn3 in the substantia nigra and Nlgn1 in the subthalamic nucleus depended on genetic background. The development of short-term cocaine appetence induced an increase in Nrxn3beta expression in the globus pallidus. Human NRXN3 has recently been linked to several addictions. Thus, NRXN3 adhesion molecules may play an important role in the synaptic plasticity of neurons involved in the indirect pathways of basal ganglia, in which they regulate reward-related learning. Show less