T cell receptor activation of naïve CD8 + T lymphocytes initiates their maturation into effector cytotoxic T lymphocytes (CTLs) which can kill cancer and virally infected cells.Although CTLs show an increased reliance on glycolysis upon acquisition of effector function, we found an essential requirement for mitochondria in target cell killing. Acute mitochondrial depletion in USP30-deficient CTLs markedly diminished killing capacity although motility, signaling, and secretion were all intact. Unexpectedly, the mitochondrial requirement was linked to mitochondrial translation, inhibition of which impaired CTL killing. Impaired mitochondrial translation triggered attenuated cytosolic translation, precluded replenishment of secreted killing effectors, and reduced the capacity of CTLs to carry out sustained killing. Thus, mitochondria emerge as a previously unappreciated homeostatic regulator of protein translation required for serial CTL killing.

Background Studies in psychiatric genetics have identified over 100 loci associated with disease risk, yet many of these loci are distant from protein coding genes. Recent characterization of the transcriptional landscape of cell lines and whole tissues has suggested widespread transcription in both coding and non-coding regions of the genome, including differential expression from loci that produce regulatory non-coding RNAs which function within the nucleus; however, the nuclear transcriptome of specific cell types in the brain has not been previously investigated. Methods Here we have defined the nuclear transcriptional landscape of the three major cellular divisions of the nervous system using flow sorting of genetically labeled nuclei from bacTRAP mouse lines. This was followed by characterization of the unique expression of coding, non-coding and intergenic RNAs in the mature mouse brain with RNAseq and validation with independent methods. Results Our findings reveal diverse expression across the cell-types of all classes of RNAs, including long non-coding RNAs – several of which were confirmed as highly enriched in the nuclei of specific cell-types using anatomical methods. Finally, we also discovered several examples of cell-type specific expression of tandem gene fusions, and report the first cell-type specific expression of circular RNAs, notably a neuron-specific and nuclear-enriched RNA arising from the gene Hnrnpu. Conclusion These data will provide an important resource for studies evaluating the function of a variety of ncRNAs in the brain, including those that may play a role in psychiatric disease.

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Background: The interaction of aging-related, genetic, and environmental factors is thought to contribute to the etiology of late-onset, sporadic Alzheimer’s disease (AD). We previously reported that serum levels of p,p ′-dichlorodiphenyldichloroethylene (DDE), a long-lasting metabolite of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT), were significantly elevated in patients with AD and associated with the risk of AD diagnosis. However, the mechanism by which DDT may contribute to AD pathogenesis is unknown. Objectives: This study sought to assess effects of DDT exposure on the amyloid pathway in multiple in vitro and in vivo models. Methods: Cultured cells (SH-SY5Y and primary neurons), transgenic flies overexpressing amyloid beta ( ), and C57BL/6J and 3xTG-AD mice were treated with DDT to assess impacts on the amyloid pathway. Real time quantitative polymerase chain reaction, multiplex assay, western immunoblotting and immunohistochemical methods were used to assess the effects of DDT on amyloid precursor protein (APP) and other contributors to amyloid processing and deposition. Results: Exposure to DDT revealed significantly higher APP mRNA and protein levels in immortalized and primary neurons, as well as in wild-type and AD-models. This was accompanied by higher levels of secreted in SH-SY5Y cells, an effect abolished by the sodium channel antagonist tetrodotoxin. Transgenic flies and 3xTG-AD mice had more pathology following DDT exposure. Furthermore, loss of the synaptic markers synaptophysin and PSD95 were observed in the cortex of the brains of 3xTG-AD mice. Discussion: Sporadic Alzheimer’s disease risk involves contributions from genetic and environmental factors. Here, we used multiple model systems, including primary neurons, transgenic flies, and mice to demonstrate the effects of DDT on APP and its pathological product . These data, combined with our previous epidemiological findings, provide a mechanistic framework by which DDT exposure may contribute to increased risk of AD by impacting the amyloid pathway. https://doi.org/10.1289/EHP10576

The primary role of the Cell Wall Integrity Pathway (CWI) in Saccharomyces cerevisiae is monitoring the state of the cell wall in response to general life cycle stresses (growth and mating) and imposed stresses (temperature changes and chemicals). Of the five mechanosensor proteins monitoring cell wall stress, Wsc1p and Mid2p are the most important. We find that WSC1 has a stringent requirement in zygotes and diploids, unlike haploids, and differing from MID2’s role in shmoos. Diploids lacking WSC1 die frequently, independent of mating type. Death is due to loss of cell wall and plasma membrane integrity, which is suppressed by osmotic support. Overexpression of several CWI pathway components suppress wsc1∆ zygotic death, including WSC2, WSC3, and BEM2, as well as the Rho-GAPS, BEM3 and RGD2. Microscopic observations and suppression by BEM2 and BEM3 suggest that wsc1∆ zygotes die during bud emergence. Downstream in the CWI pathway, overexpression of a hyperactive protein kinase C (Pkc1p-R398P) causes growth arrest, and blocks the pheromone response. With moderate levels of Pkc1p-R398P, cells form zygotes and the wsc1∆ defect is suppressed. This work highlights functional differences in the requirement for Wsc1p in diploids Versus haploids and between Mid2p and Wsc1p during mating.