Discovery of Hippo signaling as a regulator of CSPG4 expression and as a therapeutic target for Clostridioides difficile disease.

The signaling pathways and networks regulating expression of chondroitin sulfate proteoglycan 4 (CSPG4), a cancer-related protein that serves as a receptor for Clostridiodes difficile TcdB, are poorly defined. In this study, TcdB-resistant/CSPG4-negative HeLa cells were generated by exposure to increasing concentrations of the toxin. The cells that emerged (HeLa R5) lost expression of CSPG4 mRNA and were resistant to binding by TcdB. mRNA expression profiles paired with integrated pathway analysis correlated changes in the Hippo and estrogen signaling pathways with a CSPG4 decrease in HeLa R5 cells. Both signaling pathways altered CSPG4 expression when modulated chemically or through CRISPR-mediated deletion of key transcriptional regulators in the Hippo pathway. Based on the in vitro findings, we predicted and experimentally confirmed that a Hippo pathway inactivating drug (XMU-MP-1) provides protection from C. difficile disease in a mouse model. These results provide insights into key regulators of CSPG4 expression and identify a therapeutic for C. difficile disease.

Distinct pathways affected by menin versus MLL1/MLL2 in MLL-rearranged acute myeloid leukemia.

Disrupting the protein-protein interaction for molecularly targeted cancer therapeutics can be a challenging but promising strategy. Compounds that disrupt the interaction between menin, a chromatin-binding protein, and oncogenic mixed lineage leukemia fusion proteins (MLL-FPs) have shown significant promise in preclinical models of leukemia and have a high degree of selectivity for leukemia versus normal hematopoietic cells. Biochemical and structural studies demonstrate that, in addition to disrupting the menin-MLL-FP interaction, such compounds also inhibit menin-MLL1, menin-MLL2, and other menin-interacting proteins. Here, we address the degree to which disruption of menin-MLL-FP interactions or menin-MLL1/MLL2 interactions contribute to the antileukemia effect of menin inhibition. We show that Men1 deletion in MLL-AF9-transformed leukemia cells produces distinct cellular and molecular consequences compared with Mll1;Mll2 co-deletion and that compounds disrupting menin-MLL N-terminal interactions largely phenocopy menin loss. Moreover, we show that Mll1;Mll2-deficient leukemia cells exhibit enhanced sensitivity to menin interaction inhibitors, which is consistent with each regulating complementary genetic pathways. These data illustrate the heightened dependency of MLL-FPs on menin compared with wild-type MLL1/MLL2 for regulation of downstream target genes and argue that the predominant action of menin inhibitory compounds is through direct inhibition of MLL-FPs without significant contribution from MLL1/MLL2 inhibition.

Gestational age and socioeconomic status as mediators for the impact of prenatal alcohol exposure on development at 6 months.

BACKGROUND: Of the many negative outcomes associated with gestational alcohol use, one that has received relatively little attention is preterm birth and its possible contribution to effects of prenatal alcohol exposure (PAE) on development. To examine the increased risk for premature delivery associated with PAE and the joint influence of preterm birth and alcohol on child outcomes, analysis was carried out in a longitudinal cohort recruited in Western Ukraine. METHODS: Alcohol-using women and low or nondrinking controls were identified prenatally for a clinical trial of multivitamins and minerals (MVM) in ameliorating effects of PAE. Women were interviewed to provide information about medical and social status and other drug use. At delivery, information was collected about infant (N = 686) status including gestational age (GA) in weeks. Finally, 441 infants were followed to 6 months of age and cognitive (Mental Developmental Index [MDI]) and motor development (Psychomotor Developmental Index [PDI]) (measured using the Bayley Scales of Infant Development, second Ed (BSID-II). RESULTS: Seven percent infants were born at <37 weeks GA. The odds ratio for preterm delivery for Alcohol Exposed versus Low/No Alcohol was 2.6 (95% Confidence Interval 1.37, 4.94) (p < .003); MVM supplements were associated with a lower rate of preterm delivery overall, but the relative proportion of preterm births did not vary by MVM supplement status between alcohol exposure groups. In mediation models of 6 month cognitive and motor development with reference to Barron and Kenney in 1986, GA significantly mediated alcohol effects (MDI: Z = -2.64, p < .008; PDI: Z = -2.35, p < .02) although PAE independently affected both outcomes (MDI: t = -5.6, p < .000; PDI: t = -3.19, p < .002). CONCLUSION: Results suggest that PAE is associated with higher rates of preterm birth and that alcohol's effect on development in infancy may be both direct and mediated by shortened length of gestation.

Long-term nitrogen amendment alters the diversity and assemblage of soil bacterial communities in tallgrass prairie.

Anthropogenic changes are altering the environmental conditions and the biota of ecosystems worldwide. In many temperate grasslands, such as North American tallgrass prairie, these changes include alteration in historically important disturbance regimes (e.g., frequency of fires) and enhanced availability of potentially limiting nutrients, particularly nitrogen. Such anthropogenically-driven changes in the environment are known to elicit substantial changes in plant and consumer communities aboveground, but much less is known about their effects on soil microbial communities. Due to the high diversity of soil microbes and methodological challenges associated with assessing microbial community composition, relatively few studies have addressed specific taxonomic changes underlying microbial community-level responses to different fire regimes or nutrient amendments in tallgrass prairie. We used deep sequencing of the V3 region of the 16S rRNA gene to explore the effects of contrasting fire regimes and nutrient enrichment on soil bacterial communities in a long-term (20 yrs) experiment in native tallgrass prairie in the eastern Central Plains. We focused on responses to nutrient amendments coupled with two extreme fire regimes (annual prescribed spring burning and complete fire exclusion). The dominant bacterial phyla identified were Proteobacteria, Verrucomicrobia, Bacteriodetes, Acidobacteria, Firmicutes, and Actinobacteria and made up 80% of all taxa quantified. Chronic nitrogen enrichment significantly impacted bacterial community diversity and community structure varied according to nitrogen treatment, but not phosphorus enrichment or fire regime. We also found significant responses of individual bacterial groups including Nitrospira and Gammaproteobacteria to long-term nitrogen enrichment. Our results show that soil nitrogen enrichment can significantly alter bacterial community diversity, structure, and individual taxa abundance, which have important implications for both managed and natural grassland ecosystems.